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Posted by: Van B Nov 7 2021, 04:01 PM

Ok fellas, here’s the run down Aux Air Regulator (AAR) and Cold Start Valve (CSV)/injector both work fine. Many of you have also been keeping up with my high idle issue that we figured out.

But yet, when the car is cold, i.e. room temp, I don’t get the high idle I should on start-up. Instead she cranks a bit and then lumbers to life. Idle lopes around 700-800rpm and then smooths out as it warms.

In all other aspects of operation, the engine seems to be pretty happy.

Thoughts? Experience?

-Van

See post #419 on page 14 for a synopsis of the outcome.

Posted by: emerygt350 Nov 7 2021, 04:13 PM

Hmmm.... Are you sure about the aar? Just unplug it from the plenum while you cold start. See if that changes anything.

Low idle tends to be a rich condition or retarded timing.

Posted by: Van B Nov 7 2021, 04:23 PM

I took off the AAR and put 12v to it and watched it close. It definitely works.
I don’t own a timing light since my other Porsche just needs a laptop lol… but even if I got one I wouldn’t know the difference between right and wrong numbers

Posted by: emerygt350 Nov 7 2021, 04:47 PM

The aar may work but I would still just pull it and see if it changes anything. And by pull it, I mean create the equivalent vacuum leak. When I bought mine some fool had both ends of the aar plugged into the plenum.

I wouldn't worry about timing yet. Just two of the things that tend to cause low idle.

Posted by: wonkipop Nov 7 2021, 04:50 PM

mine does the same.

have done all the checks back a couple of years ago.
all perfectly timed, valves adjusted etc.
aar working and checked.

mine starts promptly and strongly. the cold start injector works and its thermoswitch as well.

once the cold star injector cuts out it goes down to a weaker idle below or at about 800,
then it comes up nice and steady after about 5 minutes.

i just let it warm up for 5 minutes before i drive it.

i'll be interested to see others answers to this one.

one thing you can check is the cold start injector and its associated thermoswitch.
i can dig that data up for you later.

there is a bit of myth around that the cold start injector only comes on below a certain termp. like an on off switch. i don't believe this is so. i believe the cold start injector operates fully below a certain temp for its full timing and above that temp the thermo switch progressively times it on for less and less duration - right up to a cut out temp which is relatively high. i will dig out all those various temp ranges for thermo switch later and post them up. others can chime in on the cold start injector/switch.

i think mr. perrine will have the facts on that.

Posted by: Van B Nov 7 2021, 05:05 PM

So, I pulled the CSV/injector today and put some tape over the manifold. Kept the CSV connected and cranked the engine. It gave a nice cooling gasoline spritz all over the engine while I was cranking the engine, but once the car started, it was content with the work accomplished and went to sleep.
So, if that’s all it’s meant to do, it’s doing a great job. But if it was supposed to do more, something is telling it not to.

Van

Posted by: emerygt350 Nov 7 2021, 07:21 PM

According to the manuals that is all it is supposed to do. Hardly seems worth it but I guess it must be important on very cold days. As mentioned above, there is a variety of opinions on how much and when with that csv.

Posted by: emerygt350 Nov 7 2021, 07:24 PM

I would add that mine starts right up and it does take a minute or so before I notice the aar making a difference. I put a valve on mine and often I just leave it closed (taking the aar out) since the car runs just fine without it in the summer. I am starting to see some more benefit now that it is getting colder. I would suggest the valve addition to anyone. It really is nice to have when troubleshooting and for setting the max idle when aar is on.

Posted by: wonkipop Nov 8 2021, 03:28 AM

sounds about right.

a couple of years ago when i was recommissioning mine the engine would run for around 5-10 seconds or so on the cold start valve alone. did not have a stop watch on it. the injectors despite reconditioning were kaput, but she would start and run off the cold start valve for a short time.

that was around the end of autumn (you call it fall). temps in workshop would have been about 15C or 60F in USA temp. the cold start definitely kicks in above 50F as others state is some kind of on/off cut off.

i was down at the workshop today working on the falcon ute so i asked mike, who is the mechanic looking after all our cars. i went over the cold idle thing with him.
my car is all set up properly tuned off the analyzer when the engine was fully warm with the correct fuel/air mix. his view is that the AAV is probably inhibiting fast cold idle.
basically they get old. they just have a sprung steel coil in them that heats with electrical current. after 50 years of cycling the thermo coil spring degrades etc. they just don't work like they did when new. the coil weakens. which means that they close a bit quicker than they are supposed to, or close enevenly or even stick and then suddenly close.

we tested mine a couple of years ago and it appeared to open and it appeared to close.
did the fridge test and then hooked it up to a battery. but its not like i timed it against any data. my memory was that it closed reasonably fast, maybe in 2 minutes or so.
which might be too fast?

anyway, i don't worry about it too much. i know the engine is set up nice with air fuel mix when its warmed up to operating temp.

i really can't shed any light on the problem other than to suspect the AAV might be not behaving as it would have 50 years ago, which is how i look at mine.

i've got a feeling it idled more strongly from cold start when i first recommissioned 2 years ago and lately its been a little weaker for the first minute or 2 of operation.
could be my imagination. if i get time i might take another look at the AAV and electrical connection. probably at christmas.

Posted by: wonkipop Nov 8 2021, 04:39 AM

ps @Van B

part of my conversation with mike today involved him saying he had never seen absolute first version L jet until he helped me recommission. you don't see that stuff in australia.
he reminded me its half a century old and it still goes. then swept his hand in the general direction of the door and said everything fresh on the road at the mo won't be even vaguely operational in 20 years time.

i was reminded of him pointing at the AFM housing on the air cleaner a couple of years back with a sh$t eating grin on his face saying its a 001 part #. you don't see that often, the first version of something.

i got told some more stories about his apprentiship tech classes when he was shown by an an older experience FI tech how to adjust a fuel pressure regulator that had gone weak. but it in the vice and squeeze it. he said this instructor could actually do it - fix up a screwed up non adjustable fuel pressure regulator. bush mechanic stuff.

Posted by: Van B Nov 8 2021, 09:17 AM

The temp switch is an interesting point. If in fact it's set for what humans would call cold weather and not what an engine would consider cold, then I may not have ever had it cold enough to truly activate the cold start. I found some document that covers some decent detail on the 912E L-Jetronic system and it mentioned exactly what you said.

Cold Start Thermo-switch:

912E = 30C/95F
914 = 15C/55F

That temp for the 914 makes zero damn sense!

I also found some wires on my dual relay that were loose. I don't understand how one side has the plastic plug and the other side looks like a hack job of different clips and pig tails?

Posted by: wonkipop Nov 8 2021, 04:16 PM

here is what i have Van.
From a L - Jet fuel injection manual for VWs generally.
see attached illustration.

3 different thermoswitches for the cold start valve are covered and listed with different bosch part #s.

would seem to imply fitting thermoswitches to suit different climate zones?
all three have different temp ranges but all having same spread of 18F between coldest and hottest.

but just to throw that off, I have another L jet guide that says the thermoswitch opens fully at 50F and closes above 104F. ?????? to me the 50 to 104 makes the most sense, as i would define an engine sitting at 104F as "cold" and needing a tiny squirt of start up fuel? or am i wrong.

anyway - all that means is thermoswitch opens cold start injector for full max timing at lowest temp, does not open it at all above the highest temp and in between its a diminishing amount of time the switch opens and the injector delivers.

in the 914 factory manual the test mentions the switch when tested below 50F should not open for more than 20 seconds. so 20 seconds is max amount of cold start injector delivery?

the truth is its really just got to work and more importantly switch the cold injector off.
to me its just a machine doing a synthetic couple of pumps on the gas pedal as you do for a carby car?

however -- thats not the fast idle warm up enrichment that takes over after the cold start injector does its job.

i know my cold start injector works, yours does too, but the enrichment cold idle phase is not quite right.





warm up enrichment is really controlled by 3 things as far as i can tell.

temp sensor 1 - in the intake air sensor of the Air Flow Meter. (intake air temp)

temp sensor 2 - the cylinder head temp sensor. (engine temp)

AAV - supplying the additional air for warm up.

and its kind of analogue like a clock, especially the AAV.

so one of those things is probably playing up and giving me the no fast idle warm up like you have on yours as well.

we tested all three of mine back 2 years ago and they all appeared to be working but i think this christmas i might re test and go over them maybe more closely.

i don't really worry about it at this stage as i know its running fine when its warm and i can put up with the little hitch starting the car cold every weekend and letting it get up to speed - and i never have to touch the gas pedal to start the car or keep it going during the warm up, so i figure its almost still all working after half a century and thats not too bad a situation for now.

Posted by: emerygt350 Nov 8 2021, 05:30 PM

Great stuff. I would add that as you find all the gremlins, stuff that used to behave badly often starts behaving well. Don't necessarily assume something is broken. I have found many of the simpler things (cht, aar) were working perfectly, just not when the hoses are messed up or there is a vacuum leak.

Posted by: Van B Nov 8 2021, 05:44 PM

We need an online database for all these manuals. I would love to have a pdf of the complete Porsche service manual… you know because the 914 IS A PORSCHE lol!

Posted by: Van B Nov 8 2021, 07:16 PM

Is the cylinder head temp sensor the one on top of the right bank next to the distributor? Aka single wire connector?

I did my one obligatory cold start this evening to see if fixing the connectors on the dual relay changed anything… it didn’t.

That said, when it’s warm it hums a long real nice and the decel valve is working like a champ.

Posted by: wonkipop Nov 8 2021, 07:28 PM

the CHT is further back on the right bank, hidden under the rear most intake manifold pipe.

the circular one in the engine tin nextto the distributor is the oil pressure switch.
it goes straight into the engine block just near where the oil cooler is.

i'm sure you have spotted the thermo switch connection to the cold start valve.
the thermoswitch is tucked under the plenum near the front right hand intake runner.

the CHT is a tricky thing to get out.
i'll try and find the page in the manual and post it up for you.

and i'm trying to remember where i got my factory manuals from as a download.
it was 10 years ago but i have a vague memory it might have been from the wonderful 914/6 GT website a guy folks in the USA must know. i think it was there. i could try and go have a look again. it was some kind of 914 resources site i found.

Posted by: Van B Nov 8 2021, 07:49 PM

I was hoping you wouldn’t tell me that was the CHT sensor lol. I traced that wire while I was warming up the engine… manifold definitely has to come off.

My thermo switch was missing the wire clip for the Bosch connector. So I robbed the one off the CSV and used safety wire for the CSV since I can reach it. I would love to know where I could buy those wire clips. My AFM is missing it’s large clip too. The safety wire works better than Ziptyes but it’s not quite snug enough.

Posted by: wonkipop Nov 8 2021, 08:07 PM

there is a technique for getting it out.

and the check values as well.


good luck (it is a bugger to get it out but it can be done),
it might have been in there for a long time - go easy with it.
you can test it without getting it out.

some other members here might want to offer some advice before you go hammer and tongs at it.




as far as i know there is not much you can do about temp sensor ! in the AFM unit.
its part of the unit.

Posted by: Van B Nov 8 2021, 08:25 PM

Wonki, I will pay you money for that manual! Give me that manual lol!

Also, thanks by the way. I’ll chop up a socket and see if I can make that tool.

IMO all these basic sensor are eligible for the modern day remove/replace strategy. They’ve served their time and have earned a retirement. I’ll test it after I take it out and if it’s still good, it earns a place in the spares box!

Posted by: wonkipop Nov 8 2021, 08:47 PM

here you are Van,
found it for you.

http://p914-6info.net/Manuals.htm

big downloads.
but you can pull it down section by section.


fabulous website.
thanks very much to the person who runs it.
you don't have to pay me, buy the bloke with the website a beer for me
i assume he lives in the USA somewhere.


i'm looking forward to your discoveries re the warm up phase.
you will get to them before me.

Posted by: Van B Nov 8 2021, 08:52 PM

Oh man this is gold! Thank you good Sir!

Posted by: wonkipop Nov 8 2021, 09:06 PM

the fuel injection section of the manual is a bit scrambled between D Jet and L Jet stuff.
you have to pick through it carefully to make sure you are reading the right bits.

Posted by: wonkipop Nov 8 2021, 09:18 PM

yeah, somehow, as a result of misfortune more than anything else i have ended up still having a car that is very intact.

a pathetic 76 hp L jet 1.8 with star steelies and original paint (with wrinkles and scars like me). my program at this point is to preserve it on as a running artefact and only get rid of any bits i find that are clinically dead. the rest of it can use a walking stick or painkillers to keep going like the owner. the nice thing about the 1.8 though is most or nearly all of them came with the sway bars so are pretty sweet in the suspension/chassis department.

i'll definitely be paying attention to what you discover digging around in yours and any good substitute items.


don't know if you have had prior experience with type 4 engines @http://www.914world.com/bbs2/index.php?showuser=8571 B, but there are a few dumb little traps in there for the unwary.
check the torque settings for the oil drain screen plug when you do an oil change.
that one caught a few folks out back in the day who were used to type 1 or type3 engines. you don't want to over tighten that one.

another handy little book that fits in your pocket is called technical specifications.
you probably know about it?
its easier sometimes to get torque settings for bolts etc in that than digging through the hundreds of pages in the manual.

Posted by: Van B Nov 8 2021, 10:59 PM

Mine came with a lifetime of records, even the original invoice! The owners manual, just like a proper manual, has all the torque specs for every bolt you’ll touch during routine service.

But now that you’ve given me a real service manual, it’s game on!
This is basically a new experience for me. I can remember my dad and grandfather building a 914 engine for my dad’s car when I was young, but I was too young to do much more than hold the wrneches.

Speaking of that screen, the owners manual gives a range of 7.4 to 9.4 ft lbs. I saw Ian said he goes to 9, but I’ll shoot for the low end if the treads are still good enough to stay tight at 8… maybe even some safety wire just for peace of mind.

This car will never hold a candle to my 996 in handling or speed, but it doesn’t have to. The experience of driving this 914 is so simple and pure I’ve started to use the term “motoring” again.

I drive the 996, but I go motoring in the 914

Posted by: wonkipop Nov 8 2021, 11:37 PM

thats great. sounds like you picked up a real nice car.

the factory manual gives the upper value on that strainer plug. 1.3 mgk. (9.4 ftibs).
i am used to using metric settings here.
i usually set it to a bit under too.


996, very good.

i run around most of the time in renault RS 172 i have had for nearly 20 years.
a bit more frenzied and raw than a 996.
can get on your nerves a bit on a long trip.
i keep a citroen xm for long trips that i don't want to get out of the car staggering around afterwards.

the 914 is a perfect antidote to them both.
as you say -

the 914 is the easiest to work on in many ways.
and parts are getting harder but not impossible yet.
the citroen is a real headache. its only a 99 and parts are getting real thin already.

Posted by: StratPlayer Nov 9 2021, 01:09 PM

I just had a microsquirt sys. installed on my 2.0. Still working out some bugs but very happy with this system.

Posted by: wonkipop Nov 10 2021, 04:34 PM

@http://www.914world.com/bbs2/index.php?showuser=8571 B

i just realised you are in maryland?
where my 914 originally came from.
Capitol Porsche+Audi. hyattsville. 1974

owners worked in DC then moved to madison wisconsin.
which is where i found the car when i lived in chicago. 1989.

been with me ever since in melb/perth/melb aus.

Posted by: Van B Nov 10 2021, 06:57 PM

I’m an Air Force transplant here since 2019. My actual citizenship belongs to the Republic of Texas.
Not much of a car culture around here… mostly a demolition derby.
There is a silver lining though, people who do love cars appreciate seeing cool cars much more because they are so far and few between.

It’s interesting about the old Porsche Audi dealer combo that existed back when these cars were new. There are only 2 Porsche dealers and 2 Audi dealers around DC these days, and I bet they don’t go back far enough to be the same dealership.

It would be cool to know where the old dealer was. I could do a recon for you one day and see what the place looks like now!

On our actual topic, I’ve got a URO replacement temp sensor II en route. I’ll plug it in and see what happens!

Posted by: wonkipop Nov 11 2021, 01:07 AM

keep us posted on the sensor.

yes texas, went there often for trips when i lived in chicago.
best little country in the whole USA.
it felt like australia and cured my homesickness.

the address for the dealer stamped in the service manual is
3110 Hamilton Street, Hyattsville Maryland.

Posted by: Van B Nov 11 2021, 07:58 AM

So, I just googled that address. Kinda sad to see that it’s nothing but a strip mall now. But when you look at it on google maps, and see the strange layout of the parking lot, you can definitely tell that it was a car dealer on a corner.

Posted by: Van B Nov 11 2021, 11:03 AM

Ok folks, I’m trying to be cool here, but I can’t f**king believe what I just found!
My car has Bosch WR7DC plugs in it, which have a 13/16” body, which doesn’t fit in the cylinder! The body bottoms out against the head when the thread is only about 2/3rds of the way in! WTF?!?
It really makes me wonder about these so called “Independent Porsche Mechanics”! I won’t name the REPUTABLE shop in Atlanta that did my PPI, whic included a compression test, but holy shit what a hack!!!!! Man I’m pissed!!!!!

Alright, let me take a breath here and ask what plug is preferred that has a M14 thread and 5/8 body?

Posted by: StarBear Nov 11 2021, 03:02 PM

On my 74 1.8L, I use NGK BP6ES. The BP6S are a bit shorter but work fine too. I don’t drive it hard; just local touring mostly.

Posted by: Van B Nov 11 2021, 03:54 PM

Well, now that I have four plugs that fit, the car definitely runs better. I’m still so pissed that a guy who sells himself on being a classic Porsche specialist could miss something so damn basic.

I also replaced the temp II sensor. No change on cold start, but it was pretty warm here today so I didn’t expect the computer to go into cold start mode based on readings from the temp switch anyway.
It does make me think about finding a temp switch that has a much higher temp window. I think modern knowledge of engine wear has taught us that getting the oil pressure up as quickly as you can provides a huge benefit to engine longevity. The reasoning of the 914 era was to overcome cold engine/oil friction so the car would stay running. Thus, it makes sense they would choose a 15C/55F temp switch.


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Posted by: Van B Nov 11 2021, 03:57 PM

BP6ES was all that I could find locally today. I might try the projected tip BP plugs in the future. But for now, I’m just glad I caught this and I have a sealed combustion chamber

Posted by: emerygt350 Nov 11 2021, 04:01 PM

Oil pressure while cold should peg to 60 at idle almost immediately.

You are still having low cold idle? Did you pull the aar hose off the plenum yet while it is running low and cold?

Posted by: wonkipop Nov 11 2021, 04:06 PM

i was expecting it find out it was a mcdonalds.

interesting about the spark plugs.

Posted by: wonkipop Nov 11 2021, 04:07 PM

i was expecting it find out it was a mcdonalds.

interesting about the spark plugs.

Posted by: wonkipop Nov 11 2021, 04:13 PM

theoretically a good tip for Van B and me.
but its a bastard of a hose to get off easily that one.
its very short and curved.
to get that off i have to unbolt the AAV and manouvre it to pull the hose.
its because its so short its virtually impossible to push it back far enough off the plenum or AAV connections.

but i tend to think it probably is the AAV.
looks like Van B's CHT test and replacement knocked that sensor out of the equation.
i tested mine in situ 2 years back and it was working so i never bothered to remove and change it.

i'm going to try and take a real close look again at my AAV at christmas and see if i can find out anything concrete about just what rate it should close at.

my mechanic thinks its highly likely it is the AAV as he thinks as they get old they get weaker and close faster as a possibility as well as the other type of failure which is they just don't work at all and are jammed either closed or open.

there is another sensor in the AFM unit. called sensor 1.
it measures the incoming air temp.
i have not gone into it apart from reading that it appears to be non replaceable.
guys who have mucked around with L jet for years would know more about it and what it might do.

Posted by: wonkipop Nov 11 2021, 04:39 PM

i've just remembered something too about the hose from the plenum to the AAV.

i redid all my vacuum hoses at recommission time.

except for the crankcase vent hose (could not get one) - but it was still ok and doesn't leak.

what i found was that the short hose connecting the AAV that i put on was collapsing because it was such a tight bend. certainly when i had everything hooked up and i revved the engine it sucked in and collapsed completely.

so i took the replacement hose off and put the original back on which was still in good condition. tested for leaks and it didn't leak anyway. the original hose was preformed to the tight curve and does not collapse either from curvature or engine vacuum.

again though, despite the hose not collapsing - i do not have fast idle so the hose is not playing a role in the case of my car.

but if that hose has been replaced and it is constricting then that would inhibit the AAV valve in some cases.

Posted by: emerygt350 Nov 11 2021, 05:24 PM

You can also do the reverse. You can pull the clean air in hose off the air filter and plug it with your thumb. If the aar is functioning at all your idle should drop even more.

To replicate the aar controlled vacuum leak you can pull any old hose of the plenum (of sufficient size, the decel valve hose would work) and see if your idle increases. That just won't be as definitive as pulling the aar hose from the plenum (or off the aar itself).

Posted by: wonkipop Nov 11 2021, 05:34 PM

yes @http://www.914world.com/bbs2/index.php?showuser=25740 , that would all work to duplicate.

what i will probably do at xmas is just unbolt the aav anyway and do the hose tests etc where i can manouvre the aav. i'll be giving it a good go over again to just see if i can make any difference.

i think you can still get new ones. they put the same AAV on 924s.
i can remember researching it and i seem to recall that i managed to source them.
those aavs that went on L jets went on to be used on a lot of other cars for quite a long period afterwards.

Posted by: StarBear Nov 11 2021, 06:13 PM

That info ( part numbers and such) would be a grand resource! New or even good used AARs not seen in 20 years!

Posted by: StarBear Nov 11 2021, 06:19 PM

My mechanic found a Volvo hose bend that fit perfectly. Pre-bent so doesn’t pinch.
That alt test is much easier, for sure.

Posted by: wonkipop Nov 11 2021, 07:04 PM

i'll dig back into my files from then and see if i can find it.
i have a feeling i might have sourced it from VW classic germany.
or something like that. someone had them was what i can remember.
the AAV went on a number of VW injected water cooled engines post the 914 L jets.

Posted by: Van B Nov 11 2021, 07:22 PM

Trouble with this little project is a I get like one cold start a day lol. Now that I’ve got the decel valve sorted, I’m gonna pull that hose prior to start tomorrow.
I’m definitely not going to bet against emery, but I’m not convinced since I already took the AAR off, cleaned, and did a function check.

Posted by: emerygt350 Nov 11 2021, 09:30 PM

It's just a step... Best move would be to pull it while it is running but pulling it first should be good enough. Just be prepared to plug the plenum.
That aar probably reduces the leak size a hair. When I was working on my pcv it would really race if pulled. Not the best thing to do to this engine with cold oil.

Posted by: Van B Nov 12 2021, 04:14 PM

Hello all,
I figured this was worth adding to the conversation even though I don’t yet know if it will result in anything toward achieving the cold start high idle.
Last night Wonkipop and I were messaging and he sent me a thread post by legend Capt Krusty. Which I then cross referenced with the manual, also provided by Wonkipop; thank you kind Sir!

http://www.914world.com/bbs2/index.php?showtopic=95771&st=0&p=1170393&#entry1170393

This morning I came out to try some cold start stuff and to my surprise, the car wouldn’t start. I thought about it and the only thing I did after the whole spark plug fiasco was make an 1/8th turn in on the air screw after a 20min drive.
The way it went down this morning is that I pulled the retard line from the distributor and left it open while capping the end at the throttle body. Car wouldn’t even try to start so I said, “guess that didn’t work” and put it all back together. However, when I tried again, the car still wouldn’t start. I got it going by adding 25-50% throttle and it stumbled to life. I left it running until it came up to temp and by that point everything was fine.
Then I pulled the retard line and idle came up… but I don’t want that when it’s warm! I spent the whole other thread figuring out how to fix that lol!

Soooo, I put my two brain cells two work and came up with the theory that the plugs have affected timing. Or more specifically, having incorrect plugs not installed correctly, required some messed up timing. I drove the car around a bit today here and there and noticed that even on hot starts, throttle was required to get it to kick over… which wasn’t an issue before.
Which brings me to right now. I bought a timing light, set it to zero advance and followed the procedure in the manual, with the added details from Krusty i.e. plugging the distributor ports and NOT leaving them open. Yeah, timing was off a fair bit. Took about an inch of clockwise rotation in total with a few trips back to the air screw to keep the car from dropping so low it would die. In the end I was able to set 800rpm and get the red line centered. Then I reconnected and adjusted the air screw to get 850rpm for idle. That step is thanks to Krusty.
I’m now waiting on the car to cool completely before I try starting again and see what/if anything changes.

Van


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Posted by: wonkipop Nov 12 2021, 05:01 PM

good stuff.

the late cap'n krusty had red hot tips.
often i just do a search here to find his methods.



i found some other stuff from the cap'n re the endless discussions about dist vac hookups on 914 1.8s.

the cap'n was firm in his view that all 1.8s came with the two vac hose hook up.
one to advance side of dist vac box and one to retard side.

he also had the best simplest explanation for how it works (the retard side at idle that is).

attached is the screen grab.




--------

but i also did some searching around in the factory manual.
and maybe got to the bottom of it.

lists two different distributors for 1.8
i definitely have the one underlined and its definitely a two port/two hose connection.
which i have still intact and original. so its never been altered and is still the way the factory says it should be (and the way the cap'n said it should be).




another page on manual.
casts light on 75s.
they have the single port (retard only) distributor.
and if the pollution gear is still hooked up on a 75, the port that faces to the rear of the throttle body and is hooked up to vac advance on distributor of a 74, is hooked up to the EGR valve on the 75.




there is a good section in the factory manual with a cross section and explanation of the vacuum advance/retard distributor.
its worth a read if you want to get your head around it.
i won't try it ends up being a complicated discussion if past threads i have discovered are anything to go by.

suffice to say at idle, only the retard line is working because the other port is closed off by the throttle plate. so only the smaller back section of the vac can is activated. retarding the timing. cap'n krusty explains how snapping the throttle open to take off instantly de-retards the timing at that point and you get a smooth take off.

and when the throttle is part open at cruise both ports work off a vacuum.
but the advance port operates a bigger vacuum chamber which overcomes the smaller vacuum chamber (called the retard). net effect of both working against each other is the bigger chamber advances the whole unit under vacuum.

there is other stuff going on of course, but thats the distributor under influence of mechanical weights. the vacuum bits are really working at idle and at part throttle cruise to do two things. lower emissions at idle and to increase fuel economy at cruise.
very 1970s. fuel crisis/pollution crisis.

Posted by: Van B Nov 12 2021, 05:23 PM

I read those pages earlier today and successfully didn’t get my head around it!
Bottom line for the tests conducted today. Both vacuum lines are staying connected. Good that what you’ve found confirms that stance.

Also, just tried a cold start and I’m right back to where I was before the spark plugs. I’d be really annoyed right now, if it wasn’t for the fact that the car is running so much better! I’m inching ever closer to getting all 76 ponies back in action! Getting plugs that seat properly made a noticeable difference and then retiming added a little more.
I mean it’s all good right? But as far as low idle on cold start, I’m right back to where I was after solving the high idle mystery.

Oh, one other thing. I used my fancy new timing light to get an empirical rpm measurement. When it starts I get a 700rpm idle. As it warms up, it climbs to the 850rpm I have set. It takes about two minutes to increase that 150rpm.
I’m aware that this is an inference, but 2min is how long it took the AAR to close when I bench tested it a few weeks ago.

Ugh, I hate being dumber than the mid-70’s!

Posted by: Van B Nov 12 2021, 05:44 PM

Found this on the YouTubes:

https://www.youtube.com/watch?v=FGEvf16nNQM


This is exactly what my car is like on cold start.

Continuing with the inference of my previous post, is there ANYONE with a 1.8L that actually gets a high idle from their car when starting from cold?
https://youtu.be/FGEvf16nNQM

Posted by: wonkipop Nov 12 2021, 06:18 PM

thats pretty close to how mine behaves on the cold start Van.
mine might even be a little weaker than that for the first 30 seconds/1 minute or so.

i should time it this weekend when i cold start.
will give you a comparison time for mine before it stabilises at its set warm idle around 850.

we will probably crack it eventually.
i'm trying to find that info i tracked down on aux air regulators/valves.
i know its the same as the one put into 924s and 944s.
but that doesn't get you any better off as its NLA for those cars too.
but there are a lot of very similar AAVs that ought to bolt straight in.
the only difference between them all is the rate at which they close and the size of the opening passage when cold.


only other thought i have is the electrical connection (wire) to the CHT.
you have a new CHT and got no difference.
i tested my CHT and it was ok.
but maybe the connection back to the ECU.
i'd have to look that up how to test at the other end.
have you done it?

Posted by: StarBear Nov 12 2021, 06:34 PM

Nope, but I like to set my idle a bit higher, at 950-1000 rpm so that might be masking it. Sealed up the connection downstream from the AAR to the air box as I couldn’t get a leak free seal. Two wraps of black electrical tape.
This is a much- needed thread. Destined to be a classic for 2-port 1.8L cars.

Posted by: wonkipop Nov 13 2021, 06:05 PM

@http://www.914world.com/bbs2/index.php?showuser=8571 B & @http://www.914world.com/bbs2/index.php?showuser=10753 .

full cold start test this morning for you.
car hasn't been started for a week so fuel system has bled down to lowest pressure.

temp = 13C (55-56F).
yep its a miserable spring day in melbourne.
arctic roaring 40s cold front coming through.

no touch nothing. car on its own.

two cranks. err err bam fires.

5-6 seconds strong start at 1000 rpm.
(i figure thats the cold start injector working - so much for 50 and below).

then idle drops to bottom of tach. don't even know if its making 750 rpm.
doesn't sound like it. but its keeping itself going steady.
this lasts for 2 minutes.

at 2 minute to 3 minute mark is the interesting bit.
this is the weakest phase.
it stumbles, barely keeps itself going but L jet just won't let it die.
comes back, stumbles again comes back, does this 3 times.

at 3 minute mark it begins getting stronger. but still not there to set idle.
stops stumbling. gets even at 800 rpm.

up to 4 minute mark stays at even 800 rpm.
can feel warm air puffing out from underneath at my ankles.

at 5 minute mark hits even 850 rpm and is strong and steady.

at 6 minute mark it hits the idle we set it to back at last service which was 950 rpm.
like StarBear we found it sat there nice and even last time we tuned it so that is where we have it.

its a full 6 minutes.

-----

i did not do the emorygt test of pulling hose off decel valve line.
like you only get one full cold chance a day (more like a week really have to shift other french things out of the way).

awful weather coming in down here.
so i probably won't get a chance for a drive today.
but i'll let it sit while i potter about doing some other stuff and try a "cool" start later to see what it does after you leave it for most of the day.

Posted by: emerygt350 Nov 13 2021, 08:48 PM

You have to do the aar tests. They cost nothing and until you do I think next steps are really hard to guess. A low idle is always retarded timing and or a rich mix on a fuel injected engine. The aar is really key for that craptastic half warm period on these engines.

Posted by: wonkipop Nov 13 2021, 09:45 PM

i just did a cool start.
its about 4.5 hours later.

i get about 1 minute of slightly wobbly idle around the 800-850 mark.
then its settles at 850 for about another minute and rises to 950 steady.

@http://www.914world.com/bbs2/index.php?showuser=25740 - yeah, i've always had a strong suspicion its the AAV when it comes to mine.

i know it works or it worked and i think it still does based on this morning. but not like its meant to new. i fully cleaned and tested it 2 years ago.
i'm pretty sure it closed from fridge cold in about 2 minutes. somewhere in my notes i wrote it down.

stone cold test start that i bothered to actually time this morning seems to point to AAV working for 2 minutes. the first 2 minutes it was running steady but at a very low idle.

then went into a strange phase for minute 2 to minute 3 - thats telling me something.
i think it wanted air but couldn't get it.

a few posts back i speculated my AAV is closing too fast.
its a wonder the one i have has lasted as long as it has.
being laid up for 15 years probably helped it get to here.

i'm not going to do your hose pull test on the decel valve.

i'm going to do a different one when i get time out at the shop when i take the car there for some other things i want to do.
i will unbolt the AAV then but leave it plumbed up and do a start where i just pull that hose off and test it all that way. also i think there is an AAV lying around off another porsche and one off something else out at the shop i can rig into the plumbing just to see what different aavs do at start up. do all my tests at same time.

i can't find anything in manuals that tell us how long the AAV is meant to take from full open to full closed. but from what i did this morning i believe it should be something around the 5 minute mark? if i can find enough AAVs lying around that i can sub in i might come up with something more than is it just not working at all.

Posted by: wonkipop Nov 13 2021, 10:03 PM

i also have just had one other thought for Van B.

i don't know why i did not think of it earlier.
probably because i never think of it.

the thermostat and cooling duct flaps for fast warm up.

i don't have them hooked up.
maybe he doesn't either?

you plain don't need that heath robinson contraption in australia.
everybody has always unhooked them on all VWs in australia since the year dot.
i know there are purists who say the opposite (but we don't live in antarctica here).
despite what the purists say they can jam in the close position.
its rare for a thermo to fail that way but its not unheard of or wasn't unheard of in the old days. if it does it will hold the flaps shut and.........

mine have been unhooked for 30 odd years.
but i have only been having the weaker start up since recommission and a little more weaker gradually more recently.

i think my AAV was always up to the job for the first 15 years back in aus in the 90s.
but now its weaker. now it can barely cope without those fast warm up flaps as well?

its a thought.

Van B will have to sniff around his thermo stat under the car and see if the flaps are all still connected to it and what state the thermo itself is in.
that might help him get his desired factory fast warm up he is after.

given the number of crappy chinese products around these days i'd be looking real hard at any thermo i bought to make sure it was the real deal and up to it.

Posted by: Van B Nov 13 2021, 10:34 PM

Lots of science going on down under today lol!
My car has a similar pattern but no stumbles.

Here’s what I’ve concluded:
- My CSV aka 5th injector only works while cranking the engine
— This is where the initial gusto on startup comes from

-2min is the average time for the heating element to close the AAR from 15C
— This is the same time my car spends at 700rpm before it starts to climb

- Even a slight vacuum leak on the manifold will negatively impact idle
— Vacuum advance is essentially inoperative at idle but retard is directly impacted via air screw
— I had to re-time again today as I found that the short tube from AAR to manifold wasn’t sealing completely
—- changed the tube and timing was off by 1 degree
—- Since the procedure on our car requires air screw adjustment prior to timing, you must retime whenever you do work that affects manifold pressure


Now, about the AAR, I’m 100% mine is fully functional. I can’t say it works as well as it should or could, but it’s working. Also, and most confusing, when it starts to close, is when the car starts to pick up rpm. Too much air and too little fuel? Should the CSV continue to add fuel after start up?
These are the things I’m wondering right now.

Van

Posted by: Van B Nov 13 2021, 10:56 PM

Forgot to attach this:


Attached thumbnail(s)

Posted by: wonkipop Nov 13 2021, 11:12 PM

re timing.
thats why i am leaving all this alone until a week at the workshop.
i know what you mean. had to thrash around with the disributor and the timing light over a leaky throttle body gasket last year.

i think i'm running tight on the air leaks front.
we buttoned all that up good a while back and smoke tested carby spray etc.

i decided to get less anecdotal today and watch what it was doing empirically against the clock instead of just what i thought i could recall.

i found minute 2 to 3 interesting and i'll talk to my mechanic tomorrow when i am out at the shop torturing myself on the falcon. i'll bet he has his usual line - "AAV"
to him thats saying the engine warming up is out of phase with the AAV closing down.
but we will test everything all over again including i think sensor ! in the AFM unit.
may as well.

its only the warm up from stone cold that is a little unusual.
the thing runs beautifully once its warm.

i am a bit inspired by your determination to get to the bottom of it and just do it.



re the CSV after start up.
my view is it does until the thermo switch turns it off.
which might be fairly quick if things are above 50F.
its basically kind of like the AAV.
its thermoswitch is heated by a current.

if i understand it right its going to work from 50 to 68F according to my L jet manual.
the thermo might take say 4 seconds to heat from 50 to 68 and cut off.
2 seconds from 60 to 64 or whatever.

and when its below 50 it takes what it takes to get to 50 and then from there to 68.
with a proviso that no matter what it is max 20 seconds. (thats the factory man test) - otherwise you are flooded.
if it goes for 20 seconds say, its probably arctic conditions like chicago in mid winter.
nothing like that would happen in australia unless you were up at ski resort.

normally its just a quick splash of fuel like a gas pedal pump?
and its not part of warm up beyond that?
given at most it can only last for 20 seconds when its really really cold.
but thats another thing i will go through at xmas with the manual and the thermoswitch.
the only difficult is that xmas in australia is summer and its usually really hot here.

Posted by: Van B Nov 14 2021, 07:03 AM

That makes sense to me. That injector definitely puts out a lot of fuel. And the fact that it's constant on while cranking puts the engine at risk of flooding. I could smell raw fuel pretty strong the day my car didn't want to start.

I'm still trying to understand the dynamics at play here from the L-jet point of view. Generally a choke phase would enrich the air fuel ratio. Maybe I'm begging the question here, but why does the idle speed improve after the AAR is closed?

I'll be out of state all week again, but when I get back, I want to pinch off the AAR and see what happens on a cold start.

Posted by: emerygt350 Nov 14 2021, 07:28 AM

Pull it off the air cleaner and cap it with your thumb. If you can feel it sucking then you know it is working.

Posted by: Van B Nov 14 2021, 07:43 AM

Yeah, I can play little dutch boy too. First will be some forceps on the short line. Prior to my first crank over. Then if there's nothing different, I'll do as you described.

Like I said on the last thread, the AAR bench tested successfully. Open, closed, opened again. It was a 70 degree day when I tested it so it wasn't fully open to start.

I'm also still really wanting to hear from someone with a 1.8 L-Jet that gets a proper high idle on cold start... I could be chasing fiction.

Posted by: emerygt350 Nov 14 2021, 07:56 AM

Forceps don't give the best seal. Is it hard to reach the air cleaner hose? I have never had the honor of mucking around with a 1.8. I was also just thinking about 1.8 and leaks. That Aar leak is pretty big and the computer? Or something must compensate for that particular, momentary, leak. If it isn't there or not what it is expecting the outcome could be pretty unpredictable. Not like the 2.0 at all.

Posted by: StarBear Nov 14 2021, 07:59 AM

All great stuff, mates! My flaps are on and working. Real thermos are available though pricey. I think I have the source (US) if needed; common to many VWs but there are two different versions.
35 F here this morning. Might try a very cold start and report.

Posted by: Van B Nov 14 2021, 08:00 AM

I'm using the forceps to see if the engine wants a richer mixture on cold start. If the forceps result in a higher cold start rpm, then my working theory will be that the engine is too lean on cold start. If the engine struggles even more with forceps on, then the AAR is not providing enough air.

We'll see... It could also result in not a damn thing lol....

Posted by: StarBear Nov 14 2021, 11:01 AM

Here's my Virgo Engineer testing this AM:
Tuneup 2 days ago. 49 degrees dwell; 7.5-8.0 BTDC (red mark on right side of V notch); spark plugs light gray coating - wire brushed and gap checked.
Set car out on driveway for 20 min @ 41F, 72% humidity; light wind, light clouds.
Deck lid open.
9:43 AM - cranked; 4-5 rumbles then steady at 1000 rpm (I tend to like my idle set a bit higher, and advance a tad more, than spec).
9:44 - 1100 rpm; steady
9:45 - 1100 rpm; steady
9:46 - 1000 rpm; steady
9:47 - 975 rpm; steady
9:48 - 1050 rpm; steady
A little idle dip at 3-5 min, then back up. (The AAR closing?)
5 mi drive to hardware store; ~ 15-20 min. Warm start @ 900 rpm; steady
7 mi drive home and around the block; ~ 15 min. Shut off. 45F. Full warm start @ 1000 rpm; steady.
Decel valve working fine (though still want to check it and adjust to 20 if needed)
Looks like all fine here in NJ!

Van B: I like where you're going with this....

Posted by: emerygt350 Nov 14 2021, 11:15 AM

It was 30F this morning. Took almost 8 minutes of cruising before the aar called it good. I assume it's the same part.

Fwiw I stole the bellows off a 1.7 van engine laying around in a friend's garage.... Seems to work well, my engine runs super cool though.

Posted by: Van B Nov 14 2021, 11:54 AM

SB, what is your idle set at?
That's not much or a high idle but at least things were moving in the proper flow.
Thanks for the vote of confidence too lol!

Posted by: wonkipop Nov 14 2021, 02:38 PM

to me that sounds right for an AAR.
- would align with about how long my engine seems to be taking to get to something close to semi warmed up. the AAR is a different beast on the D jets.



thanks @http://www.914world.com/bbs2/index.php?showuser=10753 for the weather report in NJ.
and countdown info.
does sound like the AAR on yours dips out a little bit early too - but is in better shape than mine and not in such a hurry.


pretty funny in the end.
whole thing is a kind of cuckoo clock bit of krautrock technology in a good sort of way. everything is timed but not necessarily very much is reactive.

Posted by: StarBear Nov 14 2021, 03:11 PM

Van B: After tune up I set idle screw at 1000 rpm. The car has always run best on cool dry weather.

Posted by: Van B Nov 14 2021, 03:41 PM

Ok that’s good info. So, your cold start high idle is only about 100rpm higher. I would ignore the heat soak start you had while out running errands. That’s typical of any engine, IMO.

Posted by: wonkipop Nov 14 2021, 03:49 PM

i know what you are saying.

be interested to see what you find.

i'm kind of curious about the way everything is fine on mine for 2 minutes and then there is a problem for a short amount of time.

i'll be asking mechanic at workshop about it today to see what he thinks now i can describe accurately the sequence.

Posted by: wonkipop Nov 15 2021, 03:58 AM

here is what mike (mechanic) had to say after i showed him the cold start description.

its either starving for air to burn the fuel its getting. AAV.

or its lean and does not have enough fuel. CHT.

as a starting point.

don't you love it.

but apparently it can be either.
there is a lot of fuel being splashed in there and a lot of it is condensing on cold surfaces so the air bit is important. car needs basically 10 times the amount of fuel at cold start up than when its warmed and at operating temp. i didn't realise it was that quantum!

he reminded me, it had been laid up for 15 years.
so you run it for a few months/year and see what faults develop if any.

in my car it could be that the CHT has started out ok and has progressively begun to "decay". have to retest.

or its the AAV. not opening correctly. either not opening enough at the start and not closing smoothly and timely. have to retest. he did say that 2-3 minutes was actually about right usually unless its really cold. then the thermo strip/spring is going to take longer to heat up from the colder engine block and ambient air and go a bit slower.

the thermo and cooling flaps were discussed. they could be playing into the hiccups speculated for either of other two - ie exaggerating them when its a bit colder here.
but they weren't really impacting a year ago he agreed. (i can test that with the car doing a cold start on the hoist by simply pulling on those flaps manually and easing them off, the cable is still there - which i might do when i get around to doing the other tests).

re emorygt350 idea of taking off a hose. yes. do that but....its a closed system. start the car with all hoses on. crack off a decel or aav line between aav and plenum carefully. you want to mimic an AAV valve if thats what you are after simulating. its a small ish aperture thats opening in the valve. so just crack it off like at one edge and control it.
one thing to remember is the AAV is in circuit with the AFM, so the flap might be being slightly opened with the AAV full open. i don't know that for sure, might have to dig around in the manual to see what it says.

as to what a cold start up is for a 1.8 - his view is - probably not that dramatic.
system would be trying to hold something like a normal idle from start up and not a lot more. maybe around the 1000 +/- rpm mark subsiding to 900 +/-.
and it would take anywhere from 2 minutes to 5 minutes depending on ambient.
but in australia he thought 2-3 minutes.

i'll wait until christmas to go further.

Posted by: Porschef Nov 15 2021, 10:13 AM

I’m running Ljet on a 2056 with a 9550 cam

Cold start always requires a little bit of gas pedal, it doesn’t idle high and threatens to stall if i take my foot off. But cold start has improved greatly with the 123 distributor, and by the time I drive out of the neighborhood it is pretty much good

I think I do recall others having similar issues with anything other than stock engines

It runs fine otherwise

I hesitate to add a cable/rod activated idle increase device…

Posted by: emerygt350 Nov 15 2021, 12:26 PM

Yeah, definitely if you are going to pull off the plenum. If you just pull off at the air cleaner (pre AAV) then nothing changes to the system. You then put your thumb over the line and see what happens. Do you feel it sucking? Then the AAV is open. You can let it warm as normal and keep checking on whether it is still sucking. When the idle dips that is when you would suspect the AAV is closing and you should feel it stop sucking. If it is still sucking when the idle dips then you know it isn't associated with the AAV (or at least not directly).

Or you could be like me and just install a valve right before the air cleaner.

Posted by: wonkipop Nov 15 2021, 06:48 PM

what i am getting at emery is that in an L jet you have the air flow meter flap up in the aircleaner where air enters. not so sure what D jet does, don't know anything much about D jet at all - which is what you have.

the flap is reading air flow which is also feeding info into the ECU for fuel.
if the aav in cold start is pulling in enough air that it is moving the flap thats going to be part of info controlling fuel flow maybe (as well as engine temp from CHT etc).

i was being cautious about the effect of pulling off a hose and the effect that has on more than just the AAV in an L jet engine. maybe not as simple as simply leaving off a hose.
see Van B's experience when he tried a start with a hose off.

that tap of yours is great as a test device i think.
it might be just the thing.
plumb that in where the AAV is and do a manual simulation of an AAV and timed.
that would keep the AFM in the equation.

Posted by: emerygt350 Nov 15 2021, 07:04 PM

Yes this is way different ljet to djet but the aar pulls clean air pre flap. Pulling the hose off the air cleaner will not mess up the flap in any way, that is why I am suggesting it rather than a controlled leak off the plenum. This way you can monitor the activity without disrupting our very sensitive ljet.

Posted by: Van B Nov 15 2021, 07:17 PM

That's right wonki. Bypassing the AFM will throw off the whole fueling equation. It opens more variables than it eliminates. Popping the line to the AAR to check for air draw is feasible once the car is running. But I'm opting for pinching the short line in order to keep everything else accounted for. If pinching that line during cold start makes the condition worse, then to me it makes a strong case that the AAR is not meeting air flow requirements. Conversely, you could say that the engine is being over fueled, but given the objective of higher RPM than normal for engine warm up, such a statement doesn't make sense.

So, I start the car and then pinch the line:
1. RPM increases
2. RPM decreases
3. RPM remains the same

If #1 happens, then it's a lean condition I'm suffering from during warm up. If #2 happens, then it's a rich condition. If #3 happens, then the AAR is already closed.

What am I missing?

Posted by: Van B Nov 15 2021, 07:23 PM

Emery, AFM is attached to the air filter housing. It's the sunset box on that diagram.

Subset* stupid autocorrect

Posted by: emerygt350 Nov 15 2021, 07:40 PM

Wow! That is nuts! I had looked at the layout in the Chilton's but it never hit me it was pre everything else. It seems insane to measure total air entering and then try to use a part of that total air to modify the afr. In fact it still doesn't make sense. Cake and eat it too. I must read....

Posted by: emerygt350 Nov 15 2021, 07:52 PM

Wow, so basically a pot on the throttle and a TPS on the flap, and the aar cheats the TPS on the throttle by sneaking air without moving the throttle plate. Interesting, and explains the extreme sensitivity to vacuum leaks in ljets. If it is all based on ratios of signals between those two pots...

Yeah, squeeze away or get yourself a good hydroponic valve like mine....

Posted by: wonkipop Nov 15 2021, 07:56 PM

@emery350gt

thats the point of L jet.
its actually way simpler than D jet in most ways.
its measuring air flow into the engine, what your throttle wants, before it gets to the throttle. its all downstream of the air flow meter.
which is why it plain doesn't like air leaks.

its pretty much what EFI became from then on for a long time.
just got more sophisticated with more sensors and more real time feedback.

L jet on a 914 is the proto system. its the adam or the eve, take your pick, of EFI that followed.

thats why i bought my 1.8 30 years ago.
i'm a geek. or i was one.
too old to be a geek now, just a geezer.

Posted by: wonkipop Nov 15 2021, 07:59 PM

or another way to see the aav is a temporary throttle plate for warm up only
but its still moving the air flap because its got to.

Posted by: Van B Nov 15 2021, 08:06 PM

More of a kitchen timer really lol…

Posted by: emerygt350 Nov 15 2021, 08:14 PM

Not sure if I would say simpler than djet, possibly more adaptive. As far as moving parts we are about equal. Us djets just have that crazy mps going on instead of your flapper.

And we both have the egg timer... And the decel valve. Talk about cruft.

Posted by: wonkipop Nov 15 2021, 08:31 PM

hooked up to a cuckoo clock and a windmill!

Posted by: ClayPerrine Nov 16 2021, 09:57 AM

Actually, there is no "TPS" on an L-Jet system. There is only a idle switch and a wide open throttle switch, so the ECU only knows those two states of throttle movement. And the 912-E didn't even have the WOT switch.

It was that way on the evolution of L-Jet called DME until 1995. The 964 has a switch like the 1.8L L-jet that only shows WOT or idle. The first DME to get a real TPS that actually measured throttle position was the 993.

Clay

Posted by: emerygt350 Nov 16 2021, 12:38 PM

Crazy. I am surprised just the flapper can tell the engine everything it needs, very cool. Just thinking of all the potential combinations like part throttle decel (high volume moving past a small throttle opening) vs very open throttle chugging at low RPM.

Posted by: ClayPerrine Nov 16 2021, 12:48 PM

With the L-Jet system, there is more than just the flapper. There is the cylinder temp sender, the air temp sender (located in the air flow meter), and the engine RPM. The throttle position is extrapolated from the RPM and the air flow meter information.


Clay

Posted by: wonkipop Nov 17 2021, 01:40 AM

the master has arrived ( @http://www.914world.com/bbs2/index.php?showuser=1143 ). good.


@http://www.914world.com/bbs2/index.php?showuser=8571 B .
re AAV.
porsche used the AAV on 1.8s all the way through to the first series 944.
in the 914 PET it has a 944 PN (944 606 103 00). i guess its a supersede part.

i did a bit of searching - 944 AAV problems.

this thread is good.
someone figured out how to really clean them out.
seafoam? got more gunk out of it than carb cleaner.
he further shows how it might be possible to adjust it?

https://rennlist.com/forums/924-931-944-951-968-forum/850108-early-944-aux-air-regulator-from-other-vehicles-compatibility-2.html

Posted by: ClayPerrine Nov 17 2021, 07:59 AM

I don't see why you have to fix them....

You can get a direct, bolt in replacement from FLAPS. Just get one for a 79-83 Datsun/Nissan 280ZX. It fits with no mods at all.

Nippondenso built L-Jet under license from Bosch, so it is an exact copy of the Bosch part. And it is not as expensive.

http://www.2040-parts.com/280zx-280-zx-oem-idle-air-contol-valve-regulator-auxiliary-nissan-datsun-i421153/

Clay

Posted by: StarBear Nov 17 2021, 09:17 AM

Awesome! Thanks, Clay!

Posted by: Big Len Nov 17 2021, 09:52 AM

Thanks Clay !!!

Posted by: Van B Nov 17 2021, 02:46 PM

Yeah, I’ve seen that thread. Can’t wait to be home so I can get back to sleuthing!
My little experiment should confirm a direction to focus regardless of outcome.

Oh, and none of these AARs are cheap anymore…

Posted by: Van B Nov 17 2021, 02:48 PM

What the hell is “FLAPS”? I’m not into alternative lifestyles just to let everyone know lol!

Posted by: ClayPerrine Nov 17 2021, 03:25 PM

FLAPS - Abbreviation for Friendly Local Auto Parts Store. The place you go to buy motor oil and wheel bearing grease.

Posted by: Van B Nov 17 2021, 03:34 PM

Ah ok hahaha. Yeah, I’m into FLAPS!

Posted by: StarBear Nov 17 2021, 03:58 PM

Tried it; reminded me of how much I dislike that site - WAY too many pop up ads and crap that only freezes up my computer. Never was able to check out the cleaning comment.

Posted by: wonkipop Nov 17 2021, 04:02 PM

Thanks for the datsun tip @http://www.914world.com/bbs2/index.php?showuser=1143 .
think i can rustle one of those up down here.

Posted by: wonkipop Nov 17 2021, 04:21 PM

i have the same problem with that site,but can work it if i shut some ad pop ups.

here are the screen grabs, its only one guy and two comments that are relevant.

Posted by: Van B Nov 17 2021, 04:51 PM

They are NLA as well. I’ve been looking at the later model Nissans that have a similar body but a different plug… but ultimately decided to do some more investigation on the root cause first.

Posted by: wonkipop Nov 17 2021, 05:25 PM

im guessing what clay is saying is there is info on a modern sub or alternative for the Nissan (Datsun) that is still floating around. unlike trying to find info on a sub for a 914/924/944?

i know down here the smart 911 mechanics have figured out the coolant temp sensor for a certain model holden (GM) commodore is the same as the head temp sensor on certain 911s. .....and can be screwed straight in to do the job. and you guessed it, its cheaper (of course).


EDIT

here is an ebay ad of interest maybe?


its a rebuild kit for AAV. not strictly right one, for VW Golf 1 etc. german by the looks of it. but i'm betting its so close its not funny when it comes to these things. ie 924.
how far is that from a golf passat engine of same era. or a 914.


https://www.ebay.com/itm/185166067358?_trkparms=amclksrc%3DITM%26aid%3D1110018%26algo%3DHOMESPLICE.COMPLISTINGS%26ao%3D1%26asc%3D20210609144404%26meid%3Df350815ab36d420b881361bae0a8b1ce%26pid%3D101196%26rk%3D1%26rkt%3D12%26sd%3D192423448222%26itm%3D185166067358%26pmt%3D1%26noa%3D0%26pg%3D2047675%26algv%3DItemStripV101HighAdFeeWithCompV3Ranker&_trksid=p2047675.c101196.m2219&amdata=cksum%3A185166067358f350815ab36d420b881361bae0a8b1ce%7Cenc%3AAQAGAAACALQTIy90DT3ngf9pzS5JfyL1nxE4DNpZVv1LJ9z%252BKy8Z45ia7TRzoXwcthQGe44LpjOcXgSzMMTIJ5taeq5PUo5uqfclgTxhE%252Bt6iswT%252B7L3iByaZhqGQE7u7RtzN1O6p7sYa8tSNNTtRtPMHh1%252Ff3kAMtTIBFblwbgvi55NwyoRwKeJuKCa7V3Uh5SNz%252BZZT7uyICk2sqcglPlErMYIMDxqn55j%252FKjonwrVoAz5iytQKvkdjovnJ4I21PsVLiwyguzC%252F1PJlIubz0QD5mGI2uCfbnX6ynx%252Bii5VOCPoRSyaK5ixefJ3vEWo382rP%252F%252FLDAJOEUIG65H%252B%252F1RHpbt5PtXOgixDYNG2HBL8fMdfqhBYtE%252FwGTlAl3Kwua2f3ZQy3lu%252BkiigRc2PciOeJUMmSaB2fqKnFg5%252FdEKUy%252F8x2h9Wtn94DeFNBH4%252B3WjTA6qunOcrbiFXYFbHzzTmCjKg%252FgX%252B8rcOWivqWl0Rd7O2FxZ%252Bzz9m7Zo% 252FW7lcOXEtzkI7FeFCWB8UipLFIpMjwTDpRNajivHnmRko7e19DFLL1xpZ30k2qAkXk3NLPKdJajEo
DBpfJnNQyBfVxjn1gMBxv365hcctRbo0kFSI%252Fp21iq1nGJ1Llv6ktWtghJu4P0sxL4cSXdpHFeqsAYxKQnWkPTGD%252FUNFo%252F7FLKgf253WeTse%7Campid%3APL_CLK%7Cclp%3A2047675

Posted by: ClayPerrine Nov 18 2021, 09:17 AM

Just an FYI.... the CHT for a 914 is NLA. The aftermarket ones are problematic and fail randomly.

But you can use a CHT from a 911 Carrera. It will screw in the head, and has the correct curve when warming up. But you have to change the harness to get it to plug in. Just use an L-Jet injector connector. Hook one side to the existing CHT wire, and hook the other side to ground. The Carrera sensor does not ground through the head.

Clay

Posted by: wonkipop Nov 18 2021, 04:41 PM

thanks again. might need that at christmas time.

Posted by: StarBear Nov 18 2021, 04:57 PM

Good thing I have a spare or two. Almost everything electronic aftermarket is problematic it seems.

Posted by: djway Nov 20 2021, 12:06 AM

My 2.3 build won't idle until head temp gets to 250 then all is good.
An AFM spring compromise to use the L Jet

Posted by: Porschef Nov 20 2021, 07:21 AM

Hmmmmm

This is interesting, an adjustment on the AAR? Never knew that. The 2056 probably would like more air to keep the AFM flap open to feed more fuel during cold start conditions…



Kinda what my foot does at that time

Gives me some hope…

Posted by: Van B Nov 20 2021, 03:44 PM

Alright, I’m back home today and this morning it was a chilly 4C. So, I was able to give it a proper cold start and do my little test.

First, I started the car as normal and then jumped out and pinched the short line from the AAR to the manifold. To my surprise I only got a subtle 100-ish RPM drop. I unclamped and reclaimed just to be sure, but yeah, that’s all I got.
Also, the car started no different today at 4C than it does at 15C. I thought that was interesting too.

Second, just for S’s and G’s I pulled the line from the boot to the AAR and the car died instantly. And I mean the instant I disconnected that hose. I had no time to even put my thumb over the ends. So, as predicted that is a lost cause.

Lastly, I moved the adjustment pin on the AAR all the way to the outside but got no change. I didn’t expect much really given how cold it is. I’m pretty sure the AAR is as open as it can be.

My thoughts so far:
I’m confident that everything is in fact functioning, but if I want to get the idle higher, I’m going to need more air flowing through the AAR channel during warm up.
Which means, I’m at a dead end for now.

Van

Posted by: emerygt350 Nov 20 2021, 03:52 PM

Very interesting! I am glad it dropped. That means you are rich and that is easier to deal with (I think). I would get one of those aars the guys were talking about. I doubt they are expensive. I suspect yours isn't opening enough.

Posted by: emerygt350 Nov 20 2021, 03:56 PM

On my 2.0, when I cut the aar off at cold start the idle drops 300 rpm, as the car warms the differential gets more and more. So after a few minutes of warm up it will be at 1400 rpm, and will drop to 800 when I close the valve.

Posted by: Van B Nov 20 2021, 05:12 PM

Yeah, I don’t know what they are talking about. The 280SX AARs are NLA as well and the ones you can get as NOS are just as much as the VW part. I’m not quite to the point that I’d be willing to spend money on a rebuild.

Now what would be cool is if I can devise a way to get a secondary air injection pump in the loop so that the AFM can still determine proper fueling… but that’s just me dreaming right now…

Posted by: wonkipop Nov 20 2021, 05:29 PM

@http://www.914world.com/bbs2/index.php?showuser=8571 B
yes to the datsun stuff being just as expensive.
i think i know of a datsun bloke i can ask about this though and maybe there is a substitute that is around that some folks know about. otherwise, mine is just going to get another clean!

can i ask a favour. we are researching some stuff on the history of all the vac tube set ups between dist and throttle body for 1.8s.

can you take a photo of your emission sticker thats in the engine bay?
give us a Vin date. month and year.

and take a photo of your throttle body and distributor showing the vacuum line hook ups for advance and retard. post them up here. if you got time.

Posted by: emerygt350 Nov 20 2021, 05:33 PM

Maybe that's an idea too. I think you said you checked to see if it was functioning on the bench but did you check to see if it was opening all the way when cold and holding it? Perhaps just more cleaning? The crap I pulled out of my idle bleed passage today was totally f'd up. I mean how could that much crap end up in an idle bleed?

Posted by: wonkipop Nov 20 2021, 05:34 PM

i've got some thoughts on this now.
and its to do with the retarded ignition on idle that some cars have.
for emissions.
your car may or may not have it.
see photo request above.
its the vac line off the back of the distributor that runs to the vac port on the TB.
thats the port on the TB that faces towards the front of the car.

been doing some reading about problems of cars back in the day.
weak idle at cold start up caused by above.
?????
but who knows.

Posted by: emerygt350 Nov 20 2021, 06:00 PM

Vacuum retard makes a nice idle possible...

Posted by: Van B Nov 20 2021, 07:08 PM

Never seen an emissions sticker in the engine bay. But the car is dual vacuum and was manufactured 12/73


Attached image(s)

Posted by: Van B Nov 20 2021, 07:13 PM

I never put it in the freezer to see how open it would go. But it seemed to open and close with ease. I spent my day winterizing my boat… which I was a bit late on lol. But maybe I can have some time tomorrow to mess with that a bit.

Posted by: wonkipop Nov 20 2021, 08:02 PM

@http://www.914world.com/bbs2/index.php?showuser=8571 B

thanks for photos and vin info.

if the emissions sticker is still there its on the lhs side wall of the engine bay,
just above where the relay board and the air cleaner are.

be handy to know what engine code it has written there.
be something like EC-B or EC-A.

any idea where the car might have been originally sold new.
did you get a glovebox manual? would have a dealer stamp maybe.

-

re the retard at idle.
i think you already know about this?

but for emerygt350's interest.

some, but maybe not all 1.8s hook up both sides of the double can vac on the distributor.
the small side is known as a retard can. the larger side is advance.

the small side if it is connected to the throttle body port that is downstream of the throttle plate (engine side) uses engine vacuum at idle to retard the ignition a further 3 degrees or so than 7.5 btdc (or ideal idle). what that does is make the engine reduce NOx emissions at idle. lowers combustion temp. though it also has the effect of raising exhaust temp (Still got to get my head around that bit). at that retard (about 4 deg btdc) you won't get a smooth take off at that level of retard except the minute you snap the throttle open the engine instantly comes off vacuum and the distributor snaps to 7.5 - and you do get smooth take off.
also the engine cranks and fires at 7.5 for ideal starting before it goes into its full emissions retard idle.

emery350gt -its why you time the 1.8 at 7.5 btdc at idle with the hoses off.
you get it to 850+ or -. then you put the hoses back on and do a fine tune on the idle speed after they are back on. some say to block both the hoses, but my logic tells me you only need to block the retard hose. it doesn't hurt to block both. the manual mentions nothing about blocking the hoses at all. so

i've come across some material that says this - while it was good for meeting the idle emissions standards it did cause the engine to run hotter while stuck in traffic. and it was mentioned could cause weak and stumbling warm up idle.

i'm wondering if that is a feature of our cars with both vacuum ports connected to both throttle ports. an easy test would be to pop the vacuum retard hose off the back of the distributor can at start up and see what it does. (you need to pop it off and block it just so you are not pulling any air in the port near the throttle.) basically disable the retard at idle and see if its a steadier faster warm up?

i think vw and porsche might have been doing this themselves right through 74 trying out variations as there seem to be a number of distinct versions with and without both hoses hooked up.

Posted by: wonkipop Nov 20 2021, 08:24 PM

@http://www.914world.com/bbs2/index.php?showuser=8571 B

yours is the splitting image of the setup on mine.

Posted by: Van B Nov 20 2021, 08:46 PM

@http://www.914world.com/bbs2/index.php?showuser=24231 retarding further is just sparking later and sending the exhaust out while it’s still burning.
Also, there’s no mechanical difference between blocking both the advance and retard distributor port or leaving them open to atmosphere. Either way neutralizes them. But blocking does ensure nothing gets in the port. However, I think you would want to block the port on the TB to avoid air leak.

Testing your cold start theory wouldn’t be hard. But it would be time consuming given the need for a cold engine. You would have to start the car, get it warm, pull the retard port, set air screw for correct warm idle, pinch/block line from TB, and confirm timing is correct. Then, stare at the car outside in the cold for several hours while you wait for it to cool down completely*, and start it again to see what happens.

I’ll try it tomorrow and report back.

*or go do something else

Posted by: Van B Nov 20 2021, 09:08 PM

Well, emissions sticker is there… its also gone forever. It was sprayed over when new with corrosion protection. So, not likely it would survive any attempt to reveal it.
Engine number is EC008741, but that’s the best I got. Other than it’s a US spec with the low compression pistons that provide a whopping 76hp/91ft lbs… to the crank.

Posted by: wonkipop Nov 21 2021, 02:18 AM

was thinking plugging the hose so it does not leak air into the throttle body.
you pull the lines off the distributor end to take the distributor out of the equation.
as you say the ports don't need the blocking, its the hose. you leave the hose on the throttle body ports.

i think all that would happen is the car will start just fine and theoretically should idle faster. a quick experiment is what i was thinking. then just put the line back on the distributor when finished. the retard is not there at fire up, it starts on 7.5 btdc regardless of hose on or off, vacuum kicks in shortly or immediately there after. so just go out there when its cold, pull the line off the dist. plug it. fire it up and see what happens.

thanks for explanation re hot exhaust. now i get it.

Posted by: wonkipop Nov 21 2021, 02:59 AM

sounds like an owner/dealer that knew about the dreaded battery/hell hole corrosion problem even in 1974 and did some proactive work!?

never mind.

there is one more thing you can look for when you get a moment.
these engines get white stamped numbers on their tin ware.
the number ought to still be there with a bit of luck.
if you look down on lhs side of engine between the air cleaner and the heater fan you might be able to see it. might be either 604 or 605. or it could be some other number.
its down near the snap in cover for the alternator adjustment hole.

there is a chance its on the right hand side of the tin near the battery. but more likely its on the left hand side.

there is one other thing you can look for which is the little white tuning sticker.
usually on tin on top of engine on left hand side. it might not be there any more.
fairly fragile. if it is there take a snap of it and post it up.

thanks for all the info so far. its fairly useful. trying to work out why there was an EC-A engine that had california and 49 states and then there was also an EC-B engine with the same. starbear and i have the EC-B one.
and then there is also an EC-B which had only 49 state. its fairly weird what was going on. we are trying to work out what the differences were. don't think we can ever work out the why!

yeah - the horsepower from these engines is frightening.
i took mine out for a run this morning. hit the streets early before the post lockdown zombies got on the roads. went for a run down by the docks and opened her up.
acceleration almost made my head move but maybe it was the gear changes.
i'm trying out one more theory with mine which is the gas might have gone off.
we have been restricted/locked down here so i've basically had 3/4 of a tank of gas in it for the last 4-5 months i've slowly used (i've lost track of time!) and i am wondering whether the octane has dropped. it can happen.
i will see what a cold start next weekend is like on some topped up fresh gas?

Posted by: ClayPerrine Nov 21 2021, 06:28 AM

I haven't looked at the availability of the Datsun stuff in a long time. Sorry.

But I do know there were a lot more Datsuns made with L-Jet than 914s. So the wrecking yards should have some of them.

Clay

Posted by: StarBear Nov 21 2021, 06:57 AM

@http://www.914world.com/bbs2/index.php?showuser=8571 B if you want/need a new tune up sticker (on the tin to the left of the oil filler neck I made some reproductions. PM me and I’ll mail one to you. ps: my car was produced 11/73 and has a 605 engine tin stamp; wonkipop car produced 1/74 and has a 604 tin stamp. There’s a current thread on this topic too.
@http://www.914world.com/bbs2/index.php?showuser=24231 if the photos are of your engine looks like your sticker has cracked/flaked. I think I sent you one or two some months ago?

Posted by: Van B Nov 21 2021, 10:34 AM

I’m gonna say it says 604. I almost lost what was left by wiping it lol.

Oh and @http://www.914world.com/bbs2/index.php?showuser=10753 I would love to have a sticker! Someday soon, I want to restore this engine and make it look all clean and new again


Attached thumbnail(s)

Posted by: StarBear Nov 21 2021, 01:28 PM

Yep; looks like 604 to me. Consistent with wonki’s.
For the sticker just pm me with your mail address. Will mail you one.

Posted by: wonkipop Nov 21 2021, 03:47 PM

i do have to put that sticker in.

Posted by: wonkipop Nov 21 2021, 03:56 PM

calling all 74 1.8 owners reading this thread.


wonki + starbear are trying to work out some history stuff for mr b (jeff bowlsby).
(because 74 1.8s are the best 914s right? )

if the info is still on your car this is what we need.
cars have to be unmodified and reasonably original (don't have to be in show condition, need to be unmolested).

1. Vin date.
2. engine bay emission sticker (image).
3. engine tune up sticker (image).
4. painted number on engine if its still there (image if you can).
5. distributor vacuum hose set up from dist to throttle body (image).
6. part number on the throttle body if you can read it. (image of TB).

thanks - keep those 1.8s going.

Posted by: Van B Nov 21 2021, 04:12 PM

@http://www.914world.com/bbs2/index.php?showuser=24231
I did your experiment today and here’s what I found:

-marginally improved kickover
—initial RPMs surged a little higher (900-1000RPM)
—seemed to start quicker
-warmup idle still sluggish (700RPM)
-off idle and low RPM throttle response did improve
—liked the improvement enough I think I will leave it for a while

Also, I have my idle set for 850 RPM

Posted by: wonkipop Nov 21 2021, 05:13 PM

i got the thought from vw porsche themselves.
they had two versions of the 50 state 1.8 floating around in 74.
one of them did not use the retard plumbing on the dist/TB.

did not even know there was that second version until i started doing some digging on a question for mr. b.

don't know the why of it, when the different versions kicked in or anything about it much other than there were two versions. (at least).

far as i can tell the difference was they either introduced or abandoned retarded idle.

i would have thought they needed the retarded idle for california - period.
it had harsher NOx standards in 74 than the 49 states.
but it turns out even that logic does not hold as unretarded idle versions have cali certification. and i have worked out the example in question that demonstrates that is unmolested, unchanged and the way it came. the tune up sticker proved it.



main thing is it worked for you. to some extent.

thats why starbear and i are after that information listed above from owners.
its fairly interesting in the context of L jet and its introduction.
914s and 412s being the first cars anywhere to get it.

Posted by: L-Jet914 Nov 21 2021, 11:20 PM

By VIN date do you mean production date?

Posted by: L-Jet914 Nov 21 2021, 11:22 PM

My emission sticker on my (my father's) 74 had some overspray from a trunk hinge repair done before my time. I used isopropyl alcohol on a q-tip to remove the overspray paint and it removed the paint and didn't harm the sticker. I learned the trick from a friend of mine.

Posted by: Van B Nov 21 2021, 11:48 PM

Yeah, this is 48yr old ziebart rustproofing… it ain’t coming off.

Posted by: L-Jet914 Nov 22 2021, 01:03 AM

Ah okay. No worries. I didn't know it was undercoating/rustproofing.

Posted by: wonkipop Nov 22 2021, 02:54 AM

extreme hell hole paranoia - and in 1974! ha.

Posted by: wonkipop Nov 22 2021, 02:55 AM

well both if you can work it out.
the date on the vin sticker.
and if you have your karmann # by all means.


EDIT
its great you got your dad's car.

Posted by: Van B Nov 24 2021, 04:23 PM

Alright…. That didn’t work. I guess the car wasn’t really cold when I tried it the other day. But today the car didn’t even try to start and then became instantly flooded. Total shitshow! Theeennnn I realized that even when I tighten the distributor, it can still move enough to alter timing slightly if it’s bumped or nudged.

Oh and the seatbelt interlock started messing up and so I had to fix that before I could continue on setting the car back to the way it was.

Bottom line: leave the hoses on.

Posted by: wonkipop Nov 24 2021, 05:17 PM

ah well
good thing you are the guinea pig before i go in mucking about in a month or so.

---

that fugen seat belt interlock screwed with me 30 years ago.

there was a relay still in the circuit under the passenger seat.
there wasn't one anymore after i got through with it.

Posted by: wonkipop Nov 26 2021, 04:13 PM

@http://www.914world.com/bbs2/index.php?showuser=8571 B

attached the definitive on how the cold start valve works.
your observation it only opens during cranking 100% right.



i found some more from same source regarding AAV being responsible in the main for fast idle warm up. i'm favouring my mechanic's instinct that its the AAR closing too fast in the case of my car for the idle stumble. link to source.

http://www.914world.com/bbs2/index.php?automodule=blog&blogid=472&showentry=2520

Posted by: Van B Nov 26 2021, 05:11 PM

I want more air through the Aux Air Valve… as in a bigger valve. I would rather see a cold start idle similar to what I have on my 996. 1500RPM is a good speed to get all the oil circulating and still low enough that you’re not really putting a load on the engine.

Posted by: wonkipop Nov 27 2021, 02:59 AM

i did the cold start test today with the tank top off of fresh gas.
guess what.
no idle stumble phase between minute 2 and 3.
it kind of went down after 2 minutes and was lower for a minute and then came back up and warmed up. but no nearly dying thing.

gas goes off, even after only 3-4 months? enough to upset the old 1.8
a 356 bloke i was talking to recently told me that modern gas drops octane faster than gas even 10 years ago.
we don't have the E gas stuff down here so that is not the cause.
its just modern petrol.

i can blame that bit of the cold stumble on dickhead dan?

Posted by: StarBear Nov 27 2021, 09:09 AM

I sort of saw that a few years ago but with maybe 6-month old gas, despite having stabilizer added to it. Since then have been using premium 93 octane as I don’t drive it a lot so extra $ not a big issue. Been driving it more this year, too, so gas doesn’t get stale. Helped stop the knock at low driving rpm, too.

Posted by: Van B Nov 27 2021, 09:16 AM

I don't really have a process for the 914, but in my 996 I added some race gas on every fill-up. That stuff always has good stabilizers in it and its worth a few extra ponies. One addendum though, you gotta avoid the oxygenated race fuels. I'm talking the old school highest octane you can get for unleaded.

Posted by: Van B Nov 27 2021, 11:55 AM

Just did a little test and I figured I would report my findings.

I pulled the AAV out and bridged the tubing from intake boot to plenum. The car fired up instantly from completely cold and jumped to 1500RPM!
Things were looking promising but just a few seconds later I started to get what looked like a runaway situation. The revs climbed up to 3500RPM so, I put my hand over the intake snorkel to choke it down. I let it fall to <1000RPM and then uncovered. The revs then climbed back up to 1500-1600RPM and stayed there.
However, I did notice the engine was rich and I could make out a little black smoke amongst the condensation from the exhaust.
I gave the throttle a rev to clear it out and then killed it.

As a result, I have yet again inspected the AAV, but can’t see anything wrong. Movement is free, spring tension is consistent, and it is totally clean.

So, the only thing I could see is that when I pulled it from the car, while still cold, it wasn’t quite fully open, but was close. The opening is not real large even at full opening, but that last little bit could be considered the most important since it’s part of the full ellipse shape and not the triangular (closing) side.
I’m going to leave it in the freezer for a couple hours and see what it looks like then.

My thoughts from this little experiment are that full pipe diameter is too much so, the restrictive shape of the AAV makes more sense to me now. But, and this is my hypothesis, if the spring has fatigued, I’m not going to get max flow through the valve.

Further, somewhere less than full tube size and current AAV aperture I’m getting now should be a proper high idle.

I guess I’ll see what I learn from the freezer.

Van

Posted by: StarBear Nov 27 2021, 12:52 PM

Onward!

Posted by: wonkipop Nov 27 2021, 04:30 PM

great experiment mate

i can remember mine 30 years ago as a 15 year old car. and it started up and idled fast.
maybe not 1500, but i seem to remember around 1200. could be a faulty memory, its a long time ago. but it def. started at a faster idle and came down.

looks like the AAV is a very finely tuned thing and it does not take much to get out of synch and not be just right?

as to gas. we can get three grades here. 91, 95 and 98. i've been running 95.
i might start using 98. might keep it fresh for longer. the 356 man said he had really noticed the gas going off faster for the last 5 years or so. similar problem, doesn't drive his car enough.

mine runs rich during that first warm up phase. same as yours. can see it in the exhaust and even what is being spat out in the moisture. the mechanic who helps out and looks after things no doubt observed that. probably why he was pretty sure i was the AAV? means the ECU and sensors 1 and 2 are still working close to correctly and its enriching the mixture.

Posted by: Van B Nov 27 2021, 05:59 PM

We use RON+MON/2 here in the states. That’s why our octane numbers are lower. Motor Octane is a much lower figure than Research Octane so, it drags the average down.

Posted by: Van B Dec 12 2021, 07:37 PM

Just a short update for the record:
I had noticed that on the two times I’ve driven the car at night, it would almost refuse to idle until completely warmed up. So, on a hunch, I thought maybe the voltage regulator was causing some faulty signals. There are definitely classic symptoms like dim lights at idle etc. So, after screwing up and buying a cheap replacement that didn’t fit, I spend $200 on a Bosch solid state.
Started did a cold start as soon as I installed it, no change. Man this thing struggles when cold…

I’m starting to get frustrated. And doubly so that there’s no L-Jet expertise around here. I suppose I’ll just throw parts at it for a while and see what happens. Nothing is broken so, I’m thinking there’s a possibility it could be a collection of parts that aren’t working properly.

Posted by: wonkipop Dec 13 2021, 03:04 AM

had that very chat today over lunch with mike.
he still says its the AAV and its degradation is in combination with the retarded idle. early smog stuff.
its a crude device compared to modern cars.

he had an interesting suggestion to me which was try a cold start with the aav unplugged (electrical connection) and see what it does. eventually it closes due to engine heat but that will stop the electrical coil heating and closing it. this was not as a solution, but just to see if maybe he was right.

i might try it as an experiment.

now that its warmer here (real hot today) mine is starting and warming up quickly. but not with a faster idle. the aav is effectively a choke. and i remember the auto chokes on twin carb vws were pretty much on the blink and uneven side to side after a mere 10 years. i had them unplugged back in the day and just used to sit there and warm it up until it would idle rather than deal with auto chokes. i had them wound off.

--------

i was getting the low down from mike on why vw would have disconnected vacuum advance for california. his view was it was another crude way to meet californian emissions by always slightly retarding the engine at cruise and as you came off throttle.
a trick to burn just enough hydrocarbons in the exhaust and not make too much NOx to pass the lab smog test. "crude" because they were adapting the behaviour of the double can distributor that was more ideal for the 49 state cars. ie cheap.

Posted by: wonkipop Dec 13 2021, 03:22 AM

there is probably only two other things that can influence things.

the cable and air cooling flaps affair.
i am guessing you have already worked through that?

and there is a temp sensor in the AFM that reads incoming air temp.
the procedure for testing that is in the manual you have downloaded.

the other possibility is minor sources of air leakage around the throttle body bearings.
if its leaking there the AFM can't measure it.
only a small leak but could be there and everything gets tighter as the engine warms up.

Posted by: Rob-O Dec 13 2021, 03:00 PM

I've kinda been lurking this thread for awhile now. I've been meaning to reply but have been busy.

I've got a '74 1.8L L-Jet car. When I got the car it was running the dreaded one carb setup. I sourced all the L-Jet parts and then reinstalled on my vehicle with lots of help and guidance from Clay, who lives fairly close by.

I had a low idle when cold for a long time. I won't go into everything I did to get my FI running well but thought I'd offer a piece of advice. I think you're focusing too hard on the AAV. If you've tested it and you're confident it's working then I'd move on. Personally I tried to isolate as many systems or components as I could. So for me, I removed the decal valve. I may put it back at some point when I have the time to properly test/adjust it but at the moment the car runs well without it.

I also tried to isolate the vacuum canister on the distributor. I mean, it's great for advancing or retarding the timing when it's running correctly but if there are any issues in that system it's going to cause high idle, low idle or a hunting idle. What I did was to remove the vacuum lines from the throttle body and cap off the lines. That way I felt that I was vacuum leak free as far as the lines to and from the canister. But even after I did that I still had idle issues. The vacuum canister seemed to work (when I vacuum tested it). But it wasn't until I removed the clip from the arm that attaches to the distributor plate that the issue was resolved. This was all AFTER I removed the distributor and cleaned and regreased the advance plates to ensure that they were moving (they weren't initially).

So, if you're confident that you've cleaned up the vacuum leaks on the car and everything mechanical is up to snuff, you may want to start isolating other systems like the distributor. It could be the source of at least some of the issues. I would:

1. Clean/relubricate the distributor advance plates. When you grab the rotor with the distributor in the car you should be able to turn it a few degrees. If you can't the advance plates are most likely gummed up and not allowing the weights to move as they should (and most probably they're stuck 'closed' to they don't swing out as the distributor spins).

2. I would test the vacuum canister to ensure it holds vacuum. Even if it does, I would still highly consider removing the clip that holds the arm of the vacuum canister to the advance plate (or remove the canister altogether and cover the hole left behind). Cap off the lines at the throttle body would be best but I suppose just capping the vacuum lines would work too. By doing that you're ensuring that the canister has no effect on the advance or retard of the ignition.

3. Examine cap/rotor/points/condenser (didn't see if you had moved over to something like Pertronix) and the rest of the distributor. I don't have information on the amount of play allowed in the distributor gear but you may want to look that up. My guess is that isn't the issue because excessive play there seems like it would cause a hunting idle. Reinstall the distributor. Then time the engine. Timing should be a breeze because you don't have any vacuum lines to remember to connect/disconnect.

Posted by: Van B Dec 13 2021, 07:13 PM

You definitely been saving up your posts lol! I’m gonna take this in line with your post because there are just so many things to discuss here!


I had a low idle when cold for a long time. I won't go into everything I did to get my FI running well but thought I'd offer a piece of advice. I think you're focusing too hard on the AAV. If you've tested it and you're confident it's working then I'd move on. Personally I tried to isolate as many systems or components as I could. So for me, I removed the decal valve. I may put it back at some point when I have the time to properly test/adjust it but at the moment the car runs well without it.

I mostly agree here, I think the one recent test where I bypassed the AAV and got a super high idle on cold start is an interesting result and leaves that door open. Also, I cracked the code on the decel valve on a different thread. I had high idle issues when I bought the car and came to realize that the decel valve needed to be adjusted. Opening vacuum greater than 20 in hg makes the valve work like a champ.

I also tried to isolate the vacuum canister on the distributor. I mean, it's great for advancing or retarding the timing when it's running correctly but if there are any issues in that system it's going to cause high idle, low idle or a hunting idle. What I did was to remove the vacuum lines from the throttle body and cap off the lines. That way I felt that I was vacuum leak free as far as the lines to and from the canister. But even after I did that I still had idle issues. The vacuum canister seemed to work (when I vacuum tested it). But it wasn't until I removed the clip from the arm that attaches to the distributor plate that the issue was resolved. This was all AFTER I removed the distributor and cleaned and regreased the advance plates to ensure that they were moving (they weren't initially).

I just bought a timing gun a couple weeks ago so… distributor and timing is still a lost art to me. My grandfather died in 1997 and that was around the last time I ever timed a car. That said, this one is pretty straight forward I think. I don’t know what clip you’re talking about. Haven’t seen anything like that.
Regarding disconnecting lines, I tried that and the car wouldn’t cold start at all from cold but started fine when warm. That was all documented a few pages back.

So, if you're confident that you've cleaned up the vacuum leaks on the car and everything mechanical is up to snuff, you may want to start isolating other systems like the distributor. It could be the source of at least some of the issues. I would:

1. Clean/relubricate the distributor advance plates. When you grab the rotor with the distributor in the car you should be able to turn it a few degrees. If you can't the advance plates are most likely gummed up and not allowing the weights to move as they should (and most probably they're stuck 'closed' to they don't swing out as the distributor spins).

My distributor turns real easy. If anything, I wish it would clamp down a little tighter. Last time I torqued on the distributor after clamping everything and with the timing light I could see that timing would still move a bit as I applied force.

2. I would test the vacuum canister to ensure it holds vacuum. Even if it does, I would still highly consider removing the clip that holds the arm of the vacuum canister to the advance plate (or remove the canister altogether and cover the hole left behind). Cap off the lines at the throttle body would be best but I suppose just capping the vacuum lines would work too. By doing that you're ensuring that the canister has no effect on the advance or retard of the ignition.

I’ll put the mighty vac on there and see if it holds. And like I said, I already failed at the no retard set up.

3. Examine cap/rotor/points/condenser (didn't see if you had moved over to something like Pertronix) and the rest of the distributor. I don't have information on the amount of play allowed in the distributor gear but you may want to look that up. My guess is that isn't the issue because excessive play there seems like it would cause a hunting idle. Reinstall the distributor. Then time the engine. Timing should be a breeze because you don't have any vacuum lines to remember to connect/disconnect.

Haven’t taken the distributor apart and I think I’ve beat the vacuum line thing to death, but I’m sure it’s standard points

In the end, I think the main point to your post is the one you didn’t expand on. You had a partner in working through all this. This is what I just posted about too. I’m frustrated. If [b]@http://www.914world.com/bbs2/index.php?showuser=24231 was a few thousand miles closer, I’m sure we’d have made some serious progress. But I’ve asked for shop recommendations for my area and just got chaff…. “You don’t need a shop, this forum has all the info, blah blah blah.” This forum is great, but it’s just a forum.[/b]

Van

Posted by: wonkipop Dec 13 2021, 07:44 PM

to expand on the AAV a bit.
and i realise that rightly @http://www.914world.com/bbs2/index.php?showuser=1419 has cautioned not to concentrate too much on it.

most of my components are not overly worn.
and i thoroughly checked out the distributor on mine 2 years ago - its good.

i think Rob-O is on to something when you are looking at a higher mileage greater used car. a lot of the components are suffering wear - or as the germans say. "its vorn".

i did manage to find on Ratwell's site, which is very good, some info on the AAV.
its supposed to take 5-6 minutes to do its thing.

the trouble with the AAV is knowing just how open its supposed to be at cold.
and then trying to accurately time the closure. i think mine was doing the whole thing a bit faster than 5-6 minutes. but when i tested it i wasn't really timing it or looking at it closely enough. i was just giving it a rudimentary test to see if it worked. i had not found any information around parameters back then.

my reason for focussing on it in the case of mine is i buy the theory that the heating strip in it is delicate and weakens over time due to repeated heating. to my way of thinking that means not only does it close too quick, but it also maybe is not holding the appature wide enough open at cold.

trouble is there is not much you can do about it, other than clean it.
i did find a 924 thread where a young guy had taken one apart and thoroughly cleaned it. he did note though there is not much you can do about a weakened heating metal element.

Rob-O' suggestion while good do seem to involve basically knackering the whole warm up system in a way. something i am reluctant to do.

its very sound advice to go right over the distributor and make sure its all operating sweetly.

Posted by: emerygt350 Dec 13 2021, 08:15 PM

He was describing movement on the advance/retard plate in the distributor, not whether the whole thing rotated...

Posted by: wonkipop Dec 13 2021, 11:48 PM

from what Van is describing it does not sound like his distributor is suffering from sticking advance retard pull arm (or plate as you refer to part of the same mechanism emery).
the reason i say that is you would feel that as you pulled away from stop and idle.
hot or warm. the engine would hesitate or stumble as it tried to come off the retarded idle.

but it sure doesn't hurt to go through the distributor.

van has a new CHT. and it works. so the cylinder head temp sensor is AOK

i tend to think the other sensor in the AFM is probably ok, it measures incoming air temp and does influence the mixture. it can be checked, there is something in the manual i seem to remember. if not it is in another L Jet manual i have.

what he is doing is the right way to do it. one thing at a time and tick them off.

i admire the will to make a 50 year old "automatic" clock work device behave as it should and i get why he wants it to do it. just get that engine up to heat and cut down that wear and tear.

its making me want to do it with mine.


i have a friend here, her grandfather was a mechanic and her father ran a holden dealership. together they won the bathurst 500 in 1968 in the devils number monaro (#13). her grandfather used to build exquisite clocks in his spare time to relax.
this warm up thing with a 1.8 is like clockwork but its not done with gears. but its a form of clockwork. its a timed affair in which something is possibly getting out of whack, because it all comes good once it is actually warm.

EDIT.
@http://www.914world.com/bbs2/index.php?showuser=8571 B.
i suspect its going to be difficult to find someone to sort the problem there in terms of a shop. its tough enough here. "where is the port to plug the lap top in?".

i am about to give mine a bit of a concentrated dose of attention. i spent the first three months of this year rebuilding the original bosch fuel pump after being told it was impossible. turns out its not if all that is happening is all the seals are leaking fuel.
it was harder than i thought but it was doable. so i've got to get it up on hoist and generally disable it for a while and go through it. i'm going to tackle some of this stuff physically then instead of mental thought bubbles.

Posted by: emerygt350 Dec 14 2021, 05:02 AM

It's been ages, so you might have done this already, but have you put a vacuum gauge on it?

Have you verified you are at the correct timing? Again check that the distributor is working correctly. Don't fear the distributor, super easy to pull out and clean/lubricate.

Posted by: wonkipop Dec 14 2021, 03:04 PM

i've gotten this far with the idea of rebuilding my AAV.
i'm trying to work out if i can do something to renew the resister strip/spring as well - this kit does not cover that.
i've just got to check i can get the right interior rebuild and if this is it.

what i want to do is get hold of another AAV to do it to rather than the one i have.
and there in lies the problem for now. there is a SAAB wreck lying around i have not got under the bonnet of yet. its a 74 but its D=Jet so i don't think i am going to have luck there. though i did get a spare (and now functioning) bosch roller cell fuel pump off it.

i've struck this before with the europeans that there are all sorts of rebuild kits that guys in france and germany have come up with. particularly so with citreons where some electric components and small pieces are getting very hard to get. no choice but to rebuild.

https://www.ebay.com/itm/185166067358?_trkparms=amclksrc%3DITM%26aid%3D1110018%26algo%3DHOMESPLICE.COMPLISTINGS%26ao%3D1%26asc%3D20210609144404%26meid%3Df350815ab36d420b881361bae0a8b1ce%26pid%3D101196%26rk%3D1%26rkt%3D12%26sd%3D192423448222%26itm%3D185166067358%26pmt%3D1%26noa%3D0%26pg%3D2047675%26algv%3DItemStripV101HighAdFeeWithCompV3Ranker&_trksid=p2047675.c101196.m2219&amdata=cksum%3A185166067358f350815ab36d420b881361bae0a8b1ce%7Cenc%3AAQAGAAACALQTIy90DT3ngf9pzS5JfyL1nxE4DNpZVv1LJ9z%252BKy8Z45ia7TRzoXwcthQGe44LpjOcXgSzMMTIJ5taeq5PUo5uqfclgTxhE%252Bt6iswT%252B7L3iByaZhqGQE7u7RtzN1O6p7sYa8tSNNTtRtPMHh1%252Ff3kAMtTIBFblwbgvi55NwyoRwKeJuKCa7V3Uh5SNz%252BZZT7uyICk2sqcglPlErMYIMDxqn55j%252FKjonwrVoAz5iytQKvkdjovnJ4I21PsVLiwyguzC%252F1PJlIubz0QD5mGI2uCfbnX6ynx%252Bii5VOCPoRSyaK5ixefJ3vEWo382rP%252F%252FLDAJOEUIG65H%252B%252F1RHpbt5PtXOgixDYNG2HBL8fMdfqhBYtE%252FwGTlAl3Kwua2f3ZQy3lu%252BkiigRc2PciOeJUMmSaB2fqKnFg5%252FdEKUy%252F8x2h9Wtn94DeFNBH4%252B3WjTA6qunOcrbiFXYFbHzzTmCjKg%252FgX%252B8rcOWivqWl0Rd7O2FxZ%252Bzz9m7Zo% 252FW7lcOXEtzkI7FeFCWB8UipLFIpMjwTDpRNajivHnmRko7e19DFLL1xpZ30k2qAkXk3NLPKdJajEo
DBpfJnNQyBfVxjn1gMBxv365hcctRbo0kFSI%252Fp21iq1nGJ1Llv6ktWtghJu4P0sxL4cSXdpHFeqsAYxKQnWkPTGD%252FUNFo%252F7FLKgf253WeTse%7Campid%3APL_CLK%7Cclp%3A2047675

Posted by: wonkipop Dec 14 2021, 07:20 PM

attached some stuff for @http://www.914world.com/bbs2/index.php?showuser=8571 B.

first.
testing temp sensor 1. located in the AFM. this measures temp of incoming air.
(i think its unlikely to be the problem, but why not test, takes no time).
v has already replaced temp sensor 2 (CHT sensor) so that one is good.






the warm up for L jet is in the end very simple.
AAV is like sitting there with the throttle cracked open.
moves the AFM flap - basically that makes the engine rev. kind of that dumb.
yes - there is some other stuff going on, enrichment of the fuel mix while the engine is cold. but as far as i can tell that is down to the two sensors. 1 and 2.
(i think this is why my mechanic keeps coming back to the AAV with me).

the ECUs are built like tanks, survive a nuclear war.
the damn things are still functioning after half a century.
its lunar module spec. so the routine in there is likely to be completely intact.

the AAV is adjustable. there is a nut on the back of it. there is about 1/8 inch adjustment. they can be played about with that much. you can take them apart, and you can clean them if you want to go all out. if you don't want to take them apart you can try the clean with carb cleaner or seafoam through the open hose connection ends.

this is what i shall be concentrating on first with my weak cold idle.
just making sure i believe that AAV is in correct order before digging deeper in mine.

i will probably have more luck sourcing an old AAV from the USA to pull completely apart than i would here. maybe some old volvos lying around have the AAV. more likely candidate than junkyard datsuns (all carbed here from that era).





the AFM flap itself is also a good candidate for checking.
make sure it is able to move that first little bit freely and its not sticking.
that could also be screwing with things.
ie the AAV can't suck the flap open.
its not moving much for that fast idle phase.

Posted by: Van B Dec 14 2021, 07:21 PM

Yup. There’s only one mark on this engine. Done it three times now as one was the experiment to mimic the California setup… didn’t work. I’ve also confirmed that I get 30 degrees of advance at 3k RPM.
I’m not pulling it because it’s operating as it’s supposed to. But also, I would prefer to have someone who can show me how all the bits work as opposed to blind exploration.

I will put a vacuum gauge on both ports this weekend just to confirm there are no leaks.

Posted by: wonkipop Dec 14 2021, 07:26 PM

that distributor sounds to me to be working just fine if its pulling that much advance.
at least on the advance side.

Posted by: Van B Dec 14 2021, 07:28 PM

Thanks @http://www.914world.com/bbs2/index.php?showuser=24231
I found this guy on the inter webs:
https://www.summitracing.com/parts/smp-ac358
It looks like a cost effective clone and is just about right on price when measured against the ass pain of fully tearing mine apart.

Also, as I stated a while back, I’ve already moved the nut to the outside of its adjustment… no change.

I’ll chew through that material this weekend.

Posted by: Van B Dec 14 2021, 07:31 PM

Also, can anyone tell me why the dual relay has a plug on one side and a bird’s nest on the other?


Attached thumbnail(s)

Posted by: Van B Dec 14 2021, 07:33 PM

The retard also works, obviously since idle climbs when I disconnect the line.

Posted by: wonkipop Dec 14 2021, 07:36 PM

gold.
might just have to get one of those myself.

Posted by: wonkipop Dec 14 2021, 07:47 PM

got the same plastic relay.
(think these are replacements for originals which had metal casing?
this one has been in mine since i got it, that was 1989).

plug one side.
wiring other.

Posted by: wonkipop Dec 14 2021, 07:57 PM

an original type relay.
same "rats nest".

battery acid got em?
or just plain water. sit right under dopey bit of open grill without a raintray that the porsche stylists never quite resolved?





from the EFI manual.
same rats nest.
not a relay i have dug into. or had to yet.
plug and rats nest is standard kit.

Posted by: emerygt350 Dec 14 2021, 08:06 PM

I meant how much vacuum the engine is pulling.


I also wonder about when that retard is supposed to stop. Is the AAR enough of a leak to cause the retard to stop retarding the timing? I kind of doubt it but it is possible. If so that would be a double whammy on a cold start. Retarded timing and not enough fuel and air.

Posted by: wonkipop Dec 14 2021, 08:10 PM

those distributors are unobtainium.
i also would only fully disassemble under strict observation by my mechanic.
actually i would probably just hand it across to him given that its just not replaceable.
but mine works fine and has been lubricated etc.
i'd say yours is the same.

to think a lot of these got thrown away years ago in carb conversions.

Posted by: emerygt350 Dec 14 2021, 08:16 PM

I found that my trigger points and bearings were all a little suspect so I put it on the shelf and installed a 123ignition distributor a few weeks ago. Quite an improvement and no more wear and tear on my old 009 dizzy.

Posted by: wonkipop Dec 14 2021, 08:17 PM

if that was the case it would just make it idle better (but pollute more).

these things start on 7.5 BTDC. fire on that and then immediately (almost) the retard sucks it back to around 4.

the retarded timing is what makes the warm up idle harder to achieve.
i'd say the difficulty with the cold idle van is having is a sign the distributor is wide awake, young at heart and raring to do its job holding the engine back when its trying to wake up and take some deep breaths.

the retard never stops while the engine is at idle.
its always retarded. it starts at 7.5 which is "pre-idle" but that is the only bit that is "unretarded" so to speak. i doubt it would fire at 4, or it would have a hard time firing.

Posted by: emerygt350 Dec 14 2021, 08:24 PM

Yes, that is my point. If it was designed to allow enough air to stop the retard then this problem gets worse since you are working against both issues. No clue if that is the case though. I will pull the retard line on mine tomorrow when it is in full Aar and see if there is vacuum at the port or if the idle increases more with it disconnected and plugged. Just out of curiosity.

Posted by: wonkipop Dec 14 2021, 08:41 PM

ah yes. i see what you are saying.

however at the amount of simulated throttle opening the AAV does i doubt the manifold alters from being at vacuum. which would have to be the case for it to come off pulling the retard side of distributor.

let us know how your test goes.

i tend to think the above scenario would still be a case of improving idle, not making it worse. its would let the engine idle at 7.5 btdc with a part cracked open throttle.
which is better than 4? i mean that extra retarding of the timing by the retard can is an emission mechanism, not to assist with cold start. or do i have that wrong?

Posted by: Van B Dec 14 2021, 08:43 PM

Yeah so, little to no vacuum while cranking, then on kick over, engine vacuum pulls the retard.

Not sure what this means, but if I pull the oil cap with the car running, it instantly dies. So vacuum abounds I suppose.

F**k it, I’ll vacuum test everything I can get the mighty vac on this weekend lol

Posted by: Van B Dec 14 2021, 08:45 PM

I see a 123ignition in my future, but not until I’m satisfied with the present state of tune.

Posted by: wonkipop Dec 14 2021, 08:52 PM

its all sealed.

another area you can get problems from in L jet is the valve cover gaskets.
but you would know if that was an issue. there would be oil leaks.
but the L jet does need to be buttoned up tight.

how are the gaskets in the oil cap. in good condition?

the AFM can't measure an air leak as big as the oil cap off which is leaking air straight into the hose from the AFM to the TB.

i guess the valve covers mean it can leak air via the crank case up into the PCV and from there into the same hose.

doesn't like false air from anywhere that the AFM can't measure.

i had a leaky throttle body gasket that seemed to kick in when the engine got hot.
thermal expansion. started fine. drove ok for 10 minutes, then went haywire.
i could keep it running but it would die at the lights. replaced the TB gasket with a new one from 914 rubber. problem went away. the old gasket had just gone hard.
surprised me how it managed to leak.

Posted by: Van B Dec 14 2021, 09:10 PM

I got oil leaks from everywhere. Most are just weeping but the RMS and what I think is the Speedo gear are the worst.

Posted by: wonkipop Dec 14 2021, 09:39 PM

i think i got my head around what emory is getting at.

he is saying that AAV is sufficiently strong to stop full retard of dist at warm up.
ie - when cold the distributor doesn't retard.
but your distributor might be sticking at retard. not moving.

an interesting idea.
not sure if that is so. that AAV would be sufficient to neutralise the vacuum retard and then as it closes the retard comes up to full strength and fully retards. but of course how would distributor go to full retard (to stick there) in the first place if the AAV is already open.

still - had not thought of it that way.

Posted by: wonkipop Dec 15 2021, 12:47 AM

this is where my thinking is at Van.

and i will reduce it to as simple as i can get it.

the L jet in these is a primitive open loop system.

the ECU can respond to mixture enrichment from the two temp sensors.
1 telling it the temp of incoming air.
11 telling it the temp of the engine.
and adjusts enrichment to that. ie amount of fuel - it orders the injectors to stand in line etc.

but the one thing the ECU cannot control and order around is the extra air to go with that enrichment. it can't respond to it and tell it to stay open for longer or slow down or speed up. instead it just gives it the AAV an electric current so it can operate like a clock. and as the clock gets older the ECU can't tell if its gone a bit crazy and lame and just keeps assuming its a fine young specimen of AAV.

it can tell that it has stopped opening the AFM flap but sensor 1 and sensor 2 just keep on going their merry way giving the ECU instructions about engine temp and how to dish up the fuel amount. i don't think it can do much about knowing the flap isn't opening anymore and slap sensor 1 and 2 around. its kind of dependent on its AAV clock keeping correct time without really knowing its doing it.

so the mixture goes off. goes too rich.

i think its the other way from when you unscrew the oil cap.
the oil cap unscrewed immediately leans the mixture and the engine dies.
(it can just suck all that extra air in around the idle bypass screw in the TB).

i think the scenario we are in is the mixture is too rich, and its not getting enough air and its not getting it for long enough. because the fuel marches to the tune of sensor 1 and 11.

which is bad for engine wear if so, so your anxiousness about it is well founded.
you don't want all that fuel in there dumping. you want it burning and warming up fast.

Posted by: Van B Dec 15 2021, 07:00 AM

@http://www.914world.com/bbs2/index.php?showuser=24231
That theory reconciles with this test. Also, when I ran a tube from the intake boot to the manifold, bypassing the AAV, the idle climbed way high, almost runaway even on cold start.

Posted by: emerygt350 Dec 15 2021, 07:30 AM

Just checked my 009. Full retard is 7inhg so the aar wouldnt affect that from triggering. Idle even with the aar is >17 on my djet, probably close to that on an ljet.

Posted by: emerygt350 Dec 15 2021, 07:59 AM

The more I think about that 7 the more it makes me wonder... I pull a 7 pretty much all the time unless I am accelerating or climbing. Can the vacuum be so much different in the throttle body? Must be...

Posted by: wonkipop Dec 15 2021, 04:18 PM

i'm definitely going to chase up one of those summit racing AAVs.

when i get it i will pull the one out of the 914 and sit them side by side and run current through and compare them.

Posted by: Van B Dec 15 2021, 05:24 PM

If you look at the bottom of the summit link I sent, you’ll see that there are two that use the standard Bosch plug, not sure what the difference is between them. The rest are a modified Bosch plug with the ridge offset to the side. Those all seem to go on post-Datsun Nissan cars.

Posted by: Van B Dec 15 2021, 05:25 PM

I don’t know Bernoulli, but he probably has something to say on the matter lol…

Posted by: StarBear Dec 15 2021, 05:27 PM

[/quote]

i'm definitely going to chase up one of those summit racing AAVs.

when i get it i will pull the one out of the 914 and sit them side by side and run current through and compare them.
[/quote]
Please do let us know! That could be a valuable Plan B. Mine is working fine (I think) but it is almost 50 years old.

Posted by: Rob-O Dec 15 2021, 08:43 PM

Okay, slow down here guys. Again you’re throwing out so much information there is no way anything substantive can get done.

One…thing…at…a…time.

But for the above…I’m going to disagree with you on valve cover gasket leaks. L-Jet doesn’t have head venting, doesn’t have a PCV and as such I can’t see a path where a leaky valve cover gasket is going to introduce an air leak. But I CAN SEE how the information dump would get Van losing focus on what he’s checking.

The last I saw was that parts in the distributor were gummed up. But that’s it. Are they now ungummed? Are the points adjusted? Is the cap and rotor in good condition? Are the advance plates moving freely? The advance plates are HUGE to proper operation of the distributor.

You mentioned that the distributor moves. Do you mean the whole body of the distributor? Because I can’t see how you can move forward investigating anything else if the distributor body is possibly moving. There are two nuts that hold the distributor in place. The nut that holds the distributor clamp to the engine case and the long nut that tightens the clamp around the distributor body to prevent it from moving. Test the vacuum canister.

More stuff that we can discuss after the above has been verified.

How the retard and advance works. But right now know that you time the car with vacuum lines disconnected. You time it to 7.5 degrees of advance. Which means that at idle the engine is FIRING the spark plug when the piston is 7.5 degrees BEFORE hitting the top of its stroke. The vacuum ADVANCE canister is just going to pull the advance weights into the ‘flung out’ position quicker than they normally would. But even without the canister…if your advance plates are moving freely…advance is going to happen.

With vacuum retard I don’t believe you’re pulling enough vacuum…at idle…to affect timing. That’s not the design of using a vacuum canister with retard. I believe it is…or was at the time…used to pull the advance plates closed quicker. But again…we can argue all that some other time on a different thread (or do some searching through past threads here and elsewhere). But first? That distributor has to be gone through. Timing has to be set, all ignition items need to be addressed to ensure they’re in proper working order. As I said before, don’t complicate this (or assume that something is working because of a line of thought). Pull the canister from the distributor. All the way off. You said you were sure about disconnecting the arm vacuum canister arm. To find it, remove the dizzy cap. Pull the rotor. Look at where the canister is attached to the side of the dizzy. From inside the dizzy you’ll see a metal arm running from the area of the vacuum canister to a point on the advance plate of the distributor. That small metal arm is connected to a small post and held in place with a small ‘c’ or ‘e’ clip (can’t remember which). Disconnect it (don’t drop it in the distributor!!!!!!!!!!!!!).

I’d also highly suggest a Pertronix igniter. They’re cheap (about $80 on Amazon) and let’s you do away with points and condenser). No more adjusting points and one less thing to worry about.

Posted by: Van B Dec 15 2021, 09:45 PM

Thanks Rob.
Distributor was never gummed up. Advances fine and timing is set. My comment about movement is me being less than impressed about the effectiveness of the clamp.
I will check that the canister is leak free this weekend and I’ll pull the cap off and have a look. I’m guessing the cap is what you all call the dizzy?
I still would like you to explain what’s accomplished by removing this clip if you don’t mind?

Posted by: wonkipop Dec 16 2021, 12:25 AM

@http://www.914world.com/bbs2/index.php?showuser=8571 B & @http://www.914world.com/bbs2/index.php?showuser=10753

quick question for you both.

does either of your cars have a centre console and gauges.

and of course StarBear can tell me whether it had it from the showroom.

(might have cracked these painted tinware numbers).

Posted by: wonkipop Dec 16 2021, 12:32 AM

in my case yes to all.
all fully tested 18 months back.
all functioning well. distributor. sensors. vac lines.

its not a thrashed out car i have.

the one thing i cannot measure is the AAV. in my case.
it works. but the question for me is it working right.
i have been able to find out the failure modes.
they either stick and jam up or as they age they weaken and
a) don't open enough at start.
b) then proceed to close too quickly.

thats why i am isolating it down to that.

i don't really have a problem with the way mine runs.
just Van has inspired me to sort out this warm up phase.
it has no other hiccups and runs fricken fantastic after its been going 5 -10 minutes.


i think if folks had a worn out system petronix sounds like a good idea.
i'm out to preserve the set up i have as a functioning museum piece.
......a bit like having a model T in the garage.

agree with your points re how the distributor works.
starts at 7.5 BTDC. vac retard side of distributor pulls it back to about 4 BTDC.
it does that for emissions.
there is no cetrifigal advance or vac advance coming into play at idle.
the ported vac is above the throttle plate and excluded.
and you are right its meant to come off that retard really quickly, the minute you snap open the throttle. because that amount of retard is sh*tty for taking off. so the springs snap it off fast.

its another discussion we could have about the vac advance.

i think i explained how taking the hose off the pcv introduces air into the system.
it wasn't an info dump.
its just all those things have to be tight.
thats another discussion. but the demo is simple.
undo the oil cap and the engine will stop, i've done it myself.
the rocker cover gaskets offer a similar route, probably via the pushrod tubes?
and into the pcv? its a closed system. or its meant to be.
you are correct, its not really a valve in a 1.8. its just a closed loop.

the one principle i stick to with L jet is its measuring air.
and if it can't measure it - it gets in trouble.

(and if for some reason it can't measure fuel to air its in trouble?)

Posted by: wonkipop Dec 16 2021, 02:56 AM

[quote name='StarBear' date='Dec 15 2021, 05:27 PM' post='2967219']
[/quote]

i'm definitely going to chase up one of those summit racing AAVs.

when i get it i will pull the one out of the 914 and sit them side by side and run current through and compare them.
[/quote]
Please do let us know! That could be a valuable Plan B. Mine is working fine (I think) but it is almost 50 years old.
[/quote]

yep, we are in the same spot StarBear.
so i will let you know.
50 year old model T.

we will crack it.

Posted by: emerygt350 Dec 16 2021, 06:19 AM

Dizzy is the whole thing, not just the distributor cap.

Posted by: wonkipop Dec 16 2021, 02:52 PM

we just use the cap and throw the rest away in australia.

------

yeah you got to dig down into the dizzy and lubricate the whole thing.
make sure the cam and arm are moving. that the plate is rotating freely etc.

i've done that on mine.
that was how i got my head around what those double can distributors did.
18 months ago i had misconceptions about them.
i don't since then.
there are explanations earlier in this thread and van has posted the cross section several times from the factory manual.

it can get confusing since in truth both sides of distributor do advance and retard,
both mechanically and with vacuum depending on engine revs, load etc.

but that so called retard can is only in effect at idle. its like a separate mechanism of sorts. the best way to describe it is just to study the drawing. better than words.
its limited to about 3-4 degrees of movement.
retards at idle that further 3-4 due to engine vacuum from port below throttle plate.
for emissions.
once throttle is opened, vacuum comes off and spring snaps it forward to 7.5.......
and centrigal advance takes over.

so called vacuum advance can has effects on the other side of that at part throttle cruise situations. it is able to advance the distributor well beyond the situation that the centrigal advance goes to. for fuel economy. it also dampens the way the distributor responds. VW used the vacuum can distributors with an advance can for years before the 914. to help the little 4 cylinder engines drive smoothly at cruise and for fuel economy. whereas during the same period porsche just used mechanical distributors on the 911. they were not that interested in fuel economy or smooth throttle response?

the dual can distributor is quite a neat little device if you still have one that works ok.
trouble is most of them are had it by now.

mine isnt. its got many more miles left in it yet.

hence my interest in the AAV.
i've focussed in on it having eliminated everything else.
and its a fairly esoteric point, since its only about the warm up phase.

i suspect van's problem is similar.
in terms of this particular "complaint".

i'll get around to it once i get hold of a second AAV and will be able to answer the question.

i was right a little while back on a separate issue he had when i suggested it was the decel valve. others were bombarding him with all sorts of stuff.
thats not a boast. it was just that i had a very good sense of what it was he was describing. as a result of that i can now tune up a decel valve i managed to find down here for mine. he gave us the vacuum value. i'd asked about that here before and got precisely zero response about 6 months back. no one knew.

its the same with these AAVs. no one actually knows what the parameters are for one of these things when brand new and properly tuned to the engine they were destined for.

Posted by: Van B Dec 16 2021, 06:16 PM

No console on mine from the factory. I bought some OE gauges from Tom here on the forum and was dead set on installing a console, but now that I’ve gotten used to the open floor, I’m not so sure. I’m wondering about a nice three gauge setup attached to the underside of the dash…

Posted by: emerygt350 Dec 16 2021, 08:13 PM

Yeah, don't do the console unless you need something to rest your leg on. I like mine, and rest my leg there, but I think the open cab is much more elegant.

Posted by: StarBear Dec 16 2021, 08:42 PM

Yep; mine came with Appearance Group so had the console and gauges. Think he has cracked the tin numbers codes though concur with Jeff B that it’s wacky but the data lines up! Makes us 1.8 folks “special”, eh?

Posted by: wonkipop Dec 16 2021, 09:09 PM

the clue might be that stunning ravenna green car.
thats got a dealer installed console.
at point of sale, not some later bring it in and add it job.
its in the paper work.

check it out. a factory console, but not the gauges. !!!!!
on top of that the temp sensor is not via a taco plate its using the oil temp sensor position on the top of the engine (see weird thing sticking up on a metal tube post).
all of its dealer installed.

i don't know quite what that means exactly. but its showing i guess that sometimes even the dealers could not scrounge together all the parts they needed to get a car off the floor in a way the customer wanted. ie it was not all click your fingers plug and play.

a certain amount of the cars were being built direct in the factory that way.
the console was not necessarily a distributor installed item at the main warehouses in USA or even at the dealers. though they could do it certainly to get a car off the floor the way a customer crunching them wanted it waving cash in front of their noses.

knowing the germans the last thing they would have wanted was the car up on a hoist at karmann factory with a couple of turkeys swapping taco plates over if they could possibly help it. would be better if the engines came off the rack already set up.

i went to the ford factory here once many years ago. that was interesting. the guys on the line had build sheets. they check the parts they are installing before they go in and tick them off. they were using scanners and bar codes by that time.

be interesting to see if VW archive/museum has any production line build sheets from the era on file as artefacts. i'm guessing they would have been retained by karmann.
karmann went broke a few years back and are closed now. hopefully their archive was retained by VW and rehoused?

EDIT

where you get the real picture is some of the stuff stamped all over the back of beetle engines. there can be up to three of these number codes. they used M and then three numbers. so there will be three slightly haphazard stamps there.
in the case of the type 1 engines thats already been worked out by kooks even crazier than me. and its all engine spec apparently. one of them will show what carb is on it.
another whether is a carbon cannister hook up. etc. so instead of just one number to describe what it is, it gets really cuckoo clock and the things cop up to three stamps.

probably by the time they set up the hamburg factory to make type 4 engines some rationalist stepped in and reordered the system to get rid of the austrian accounting methods.

Posted by: emerygt350 Dec 17 2021, 09:28 AM

Just thought I would post my warm up.
Starting (40F) (no touching the gas pedal)
https://youtu.be/5Nm7N8xJ4P8

2 minutes later
https://youtu.be/IzlGgfP5KEA

After 15 minutes driving around.
https://youtu.be/6q2CMoWxn1c

It took a good 15 minutes for it to finally go off the AAR.

My idle afr looks a little lean but it smells good so I think I might leave it there.

Posted by: Van B Dec 17 2021, 07:29 PM

That’s with your manual valve right?
Looks just right!

Posted by: emerygt350 Dec 17 2021, 07:48 PM

Yes, with it full on it goes up to 1800 or so after a couple minutes, which I find a little excessive.

Posted by: Van B Dec 17 2021, 09:22 PM

Maybe a little high, but also, running 20W-50 requires a little more effort to get it warmed up and flowing well.

Posted by: emerygt350 Dec 18 2021, 05:57 AM

Yeah, I use 5w40 synth. I want my oil to reach the bearings as fast as possible on cold start up. I have plenty of oil pressure so it works fine on my engine.

Posted by: wonkipop Dec 18 2021, 06:50 AM

yeah, i'd like to get the L-jet to do that idle straight up off cold.

my renault, only 20 years old still does 1200 straight off, takes up to 5 mins to settle to warm idle depending on ambient temp. big citroen v6 much the same.
if i can get the L jet to do similar number i'd be happy.
not fighting real cold here. it never really gets below 45F.
today it was 90.

Posted by: wonkipop Dec 18 2021, 03:55 PM

to clarify the distributor thing.

if the retard side of the vac can was no good, i don't believe it would have any effect on idle. where you would notice it is opening the throttle. the car would not pick up revs as brightly. might stumble slightly. it would be harder starting. thats with the timing done to spec at 7.5 btdc at idle.

the way that side of can works is in unison with the distributor at idle with the weights at rest. as soon as the vacuum comes off, the spring in that part of the can set up shifts advance forward (probably something like 3-4 deg). its a little tricky thinking through how that works exactly as the description in the manual seems at slightly at odds with way you go about setting the timing initially with the hoses off).

the AAV def gets you the higher warm up revs with extra O2 for the richer start up mixture - and without upsetting the vacuum can and its draw from the port near the throttle plate.

the other side of the can is going to do nothing in relation to the problem discussed here.

what am i saying?
if the cans are shot. (but i don't think Vans are).
one way around it is to work out what the ideal timing is without provision for emissions?
because i think that 7.5 btdc is the emissions setting. this is the bit i am still trying to figure out. does it stay at 7.5 and get snapped forward by the can coming off, or does the can hold it retarded further back than 7.5 and let it come back to that when it comes off.

what you are getting at @http://www.914world.com/bbs2/index.php?showuser=8571 B ?, if replacing the distributor with a purely mechanical one. finding out that ideal idle timing setting?

@http://www.914world.com/bbs2/index.php?showuser=25740 - you just manually turn that tap in the hose while you are warming the car up. get out and close it up a bit more as you are driving around for the first 10 minutes? or do you warm up the car standing still and just gradually close it? i'm going to get one of those taps for my experiments.

Posted by: wonkipop Dec 18 2021, 05:18 PM

i pulled my old haynes manual down off the shelf.
i remembered its real light on L jet stuff but has the material covering the twin carb 1.8 for europe with no emissions gear.
the timing is 7.5 btdc for the carb engine. it does not even use a retard can distributor.

i sorted out the description that was confusing me a little bit in factory manual this morning. i was right with my much earlier views. you set it up ideal at 7.5 and the can does the rest by retarding it further by slipping the plate forward and losing whatever it is - 3 to 4 degrees of advance. and it comes off instantly once vacuum is lost when throttle opens. to my way of thinking if the vac can is shot that means nothing detrimental is happening anyway in terms of a strong idle. maybe if the pull rod was locked up it might cause problems, but they would be a lot bigger than a weak idle, it would be retarding you by 3-4 deg permanently as the weights tried to do their job. bog everything down all the way. and it would have to be locked up in the full vacuum position. the springs inside the can naturally rest it in the neutral position if diaphrams fail.

they also list 4 different types of distributor for 1.8s in the factory manual, but only two in the parts manual. as far @http://www.914world.com/bbs2/index.php?showuser=10753 and I can work out its only the two. (but they do list two different rotors!).


---

the californian version of the 74 dist. was perverse. they left the advance hose dangling in space to ensure the distributor always worked in retard action in engine vacuum conditions. even at cruise. I'm trying to work out from the parts manual another piece of business which is the use of a speed limited rotor with some distributors and not others.
there could have been two scenarios. trying to get to the bottom of that. either 74 for one rotor and 75 for the other. or california 74/75 for one and 49 states for the other.
they don't make it easy to work out in the manual because it seems to contradict the parts catalogue. but i guess its to do with having vac advance or not?

Posted by: emerygt350 Dec 18 2021, 06:00 PM

The valve I put on the AAR is only there to tame the AAR itself. So I just close it a tad (to taste) and don't touch it again. It really has no effect except limiting the max rpms during warm up. It is great for troubleshooting though.

Retard doesn't have a performance effect, although I have noticed all kinds of goodness when I switched my 123ignition distributor to advance rather than retard. It is one or the other on those.

Careful using terms like "adding more O2 leading to a richer mixture". Normal people will look at you strangely.

If van b's car runs perfectly warm, and idles perfectly warm, I would add the valve and take the AAR out of the equation while manually adjusting the air with the valve, if everything is perfect than maybe a new one is all that you need. That would also tell you if the new one was doing what you need it too. If you put some Nissan AAR on there and it doesn't work, it may just not be doing what you want, not that there is some other issue and it wasn't the AARs fault. Those valves are 3 dollars at garden supply stores.

Posted by: wonkipop Dec 18 2021, 06:11 PM

i know.

but i did say for the richer start up mixture.
it is enriched by the ECU.
its the thing sending more fuel.
with an AAV you are adding the O2 that amount of ECU commanded fuel wants.

so i think i have that right.
its not causing the richer mixture.

not like a choke. which causes the richer mixture in a carb sucking more fuel out of the jet by increasing the velocity of air flow past the jet.

-----

yes i am thinking what i could do is just use your hose and tap for some troubleshooting experimentation by doing a manual version of the AAV with the AAV right out of the equation. run an alternative from the plenum with your hardware store tap on it from plenum to intake boot. just to work out if i can make a difference. run it over an approx 8 minute period. i can do that before i get hold of another AAV - which will have to come from the states and go through all the usual freight chaos we seem to still be having.

Posted by: wonkipop Dec 18 2021, 06:23 PM

i can do one other trick manually too.
all the cooling flap gear still works on mine.
i just have the cable disconnected.
i can hold all that shut manually easily from on top of the engine for a test warm up and see if it makes any difference to the wobbly stage it goes through from minute 2 to 4.
won't make it idle higher from the initial start, but be interested to see if anything happens a little further on in things.


last time i looked the thermo still looked fully compressed but i haven't operated it in years. could pull it off and test it in the sauce pan. i think i want a new one at this point if i hook it all up again more permanently.

Posted by: emerygt350 Dec 18 2021, 06:35 PM

I was reading the old Volkswagen bible the other day and the author made a good argument for keeping the bellows and flaps working even in warm places. Less time with oil not at running temperature the better.

I just think the flap design is so cool I just need to have it working.

Posted by: wonkipop Dec 18 2021, 10:29 PM

yeah, i'm coming back around to it.
it is cool.

Posted by: StarBear Dec 19 2021, 08:44 AM

Yep; I’ve always kept the flaps and bellows operational. Who am I to dispute 1960s German engineers?

Posted by: Van B Dec 19 2021, 09:50 PM

Checked vacuum hold on the distributor today, it holds 25” on both sides no problem. I also pulled the cap and everything is as it should be. Points are Bosch type and Judging by the zinc coating, pretty new.

Posted by: emerygt350 Dec 20 2021, 06:17 AM

Did the plate move freely and return home nicely when you took the vacuum on and off? Twisting the rotor by hand and seeing if it returns home is also a good test to see if the weights are gummed up. George H. has a nice video where he goes over that as well.

Posted by: Van B Dec 20 2021, 12:07 PM

I know it all works. idle climbs and descends as it's supposed to when I remove or connect the lines.
honestly, I just do these things so the few of you who are helping me figure out why the cold idle feature isn't working will be satisfied.

a distributor problem is a red herring IMO. The attributes of a distributor problem would affect all ranges of operation not just idle at cold start. I've verified retard at idle, and full advance at 3k RPM.

the most interesting clue to date was when I bypassed the AAV and connected straight from the intake boot to the manifold. That resulted in a massively high idle during cold start... nearly 3.5K!

Posted by: emerygt350 Dec 20 2021, 12:28 PM

Just trying to make sure all the easy stuff is covered... The reason why it matters is you can't time it correctly if the plate is not moving freely. Timing affects idle.

Posted by: wonkipop Dec 20 2021, 04:37 PM

there is a checklist procedure for the distributor vac cans in the shop manual you downloaded van. at different rev ranges. if you really wanted to be sure the cans were working properly. Group 1 engine, section 2.3 - 2/4 for a couple of pages after that. =
....if you got an hour to waste. sounds like it works though.

anyways merry xmas gentleman. been fun going over this stuff. got myself a checklist thanks to all this and i can go down the rabbit hole and disappear for a day or two in the shop.

thanks to emery i'll muck around with a tap for fun.

i've been getting my 94 falcon ute (aussie ranchero?) ready to paint lately so i've been neglecting the 914. time to get back into it. see if my rebuilt orig fuel pump can really last more than 5 minutes after i put it back in the car.

Posted by: emerygt350 Dec 20 2021, 05:03 PM

I am to the point now where I am running out of stuff to fix. My damn mustang needs the transmission rebuilt but that is beyond anything I would attempt. Oh well. My sister in law from Bavaria will be here tomorrow so I can have fun with her and the Porsche. When her father found out I had a Porsche he said "I have never heard of a 914"

Posted by: Van B Dec 22 2021, 12:00 PM

been on a little bit of a tangent the last couple days in my google searching. I started thinking about the fact that the thermo time switch aka temp sensor is NLA... and I realized it might be good to find a comparable replacement that is readily available. I've been pulling on the 912E part number thread to see where the supersession goes and it looks like there may be some options out there.
Unfortunately, info is hard to come by and silly things like thread pitch can be a problem. I think I'll head down this rabbit hole for a while and see what comes of it. If I can come up with a readily available $20 replacement part that works, then I think it will be worth it.

Merry Christmas!

Van

Posted by: StarBear Dec 22 2021, 04:29 PM

would like to see this happen! Onward!

Posted by: StarBear Dec 24 2021, 11:00 AM

Saw this in the current Pano magazine (Tech Q&A) - the 1999 version of the AAV for a 911! Same principle and purpose, but a "more reliable" approach.

Posted by: emerygt350 Dec 24 2021, 06:20 PM

In this case it's probably an emissions measure. You pump extra air into the exhaust (often right near the exhaust port during warm up) to help burn off any extra unburnt fuel. After warm up (in some cars) the air then moves down to the cat. Modern cats mostly don't need this.

Posted by: Van B Dec 24 2021, 09:51 PM

I have a ‘99 996 and this pump feeds directly into the manifold. It works like champ. Runs during cold start to achieve the required high idle, which is around 1200RPM, and also kicks on anytime idle needs to be bumped up. So for example if the A/C kicks on, then the secondary air injection pump will kick on to boost idle.
There is also a bypass valve at the throttle body but it’s operation is harder to detect since there’s no noise that makes it obvious.

Posted by: emerygt350 Dec 25 2021, 06:17 AM

That is so strange. Why would you pump air into a vacuum?

Posted by: Van B Dec 25 2021, 09:23 AM

Same as cracking the throttle open. The more you open the throttle, the closer your MAP gets to atmospheric on a naturally aspirated engine. Obviously forced induction engines spend most of the time above atmosphere. But Lambda/oxygen sensors were game changers in that fuel ratios were no longer dependent on measuring intake air in order to adjust fuel mixture. Now cars measure air coming in and exhaust burn coming out and can adjust based on one or both.

Posted by: emerygt350 Dec 25 2021, 10:44 AM

I suspect it is going into the exhaust manifold unless you are talking about something other than the secondary air pump. I googled it.

Posted by: Van B Dec 25 2021, 01:06 PM

I think we’re talking about the same thing but from two different perspectives. The secondary air injection pump is plumbed straight to the manifold on the 996, which means it bypasses the MAF. But since the car has oxygen sensors, it’s still able to adjust the fuel mixture, unlike the 914.
So, if a secondary air injection pump were to be used on a 914, it would have to be piped into the airbox so that the air could be measured by the AFM.

Posted by: emerygt350 Dec 25 2021, 03:10 PM

They are entirely different devices. Secondary air pumps into the exhaust manifold. On the 996 it is that way as well. It isn't for idle it is for emissions.
It adds the air after the exhaust leaves the combustion chamber as it is heading out to the cat. That is the upstream circuit. Downstream kicks in after warm up and sends it to the cats on many older cars.


The are also called smog pumps. This is also during open loop so the O2 sensors have nothing to say about it.

https://p-car.com/996/diy/sai/mainpage.html

Posted by: wonkipop Dec 25 2021, 04:18 PM

sounds correct if you were pumping..........
except it might want to leak out the other direction through the intake snorkel rather than push through the flap.

i found an AAV yesterday on a 88 saab in a mates garden graveyard.
i won't be taking it off his car for now - we cut it out of undergrowth to see if we can get it mobile to move it around. if it won't start and move it goes to the wreckers so i'll pull it then.
but..... i know where to look now. fuel injection cars were rarer on the ground in aus in the 80s. the datsuns didn't run L jet of that vintage. there were stacks of these saabs around back in the 80s.




as to emery's observation re air (smog) pumps.
yes the 75 914 2.0s had those.
different kettle of fish than what van is talking about.

on the topic of emissions what i have discovered in old epa material is that the warm up equipment on cars of that era is "emissions equipment".
known as Auxiliary Emission Control Devices. AECD. these were the devices the EPA allowed on cars to let engines warm up or to switch on to prevent engine damage.
the devices could over-ride or turn off emissions equipment (ie an EGR etc).

thats why the nut on the AAV is sealed with a little bit of goop and its hard to take one apart. its an emission device. dictated as tamper proof.

the warm up sequence of these cars post 72 is an EPA dictated time period or distance travelled measure when the car is excempt during the prototype and production line tests from meeting emission levels. after the time/distance period (and the engine is warm) the measuring starts. the EPA did not allow for the engine to come to temp according to a temp gauge, it dictated it ocurred within a certain time and distance travelled after the car was switched on cold. if your car could get to operate temp before the measuring started, bonus, but if it did not then whatever it was spewing out the tailpipe got measured as part of the test,.....bummer.

the EPA certification testing by manufacturers was done on a rolling road.
by the manufacturer at their factory.

Posted by: wonkipop Dec 25 2021, 04:27 PM

by the way, if you read the factory manual and find yourself puzzled by the way 68F keeps coming up for testing various little items, thats where it comes from.

its the EPA test min temp. so you measure electrical resistance etc or whether something opens or shuts at 68F. instruction is typically to discard the part and fit a new one. its all emissions.

i was thinking about the emission warranty that was offered on these cars back then.
50,000 mile or 5 years. a smart cookie owner could have really had fun with that one.
you could just about call everything supplying fuel/air into the engine an emissions device and get them replaced under warranty. most folks would not have realised.


anyway. the epa test dictated to manufacturers in 73/74 has the time period imbedded in it for the warm up sequence to run. if we can find that. - thats about how long the AAV opens for and the ECU runs its enrichment.

in my view, if you have a healthy sensor 1 and 2 (intake sensor, cht sensor) and a functioning ECU (those things are military grade spec and could survive on mars) then i believe that side of things is covered. the only thing that can upset what the sensors and the ecu is commanding is the AAV when it comes to warm up. (remembering this car of Vans and mine run just fine and dandy once warm).

Posted by: Van B Dec 25 2021, 04:38 PM

Ok so we’re not talking about the same thing.

Posted by: emerygt350 Dec 25 2021, 06:27 PM

Yeah, exactly. I have learned through my time fixing what others had done to early injection systems that you can often tune a car to be fine at warm up by bypassing/twiddling with something and until all of it is correct the car isn't actually doing what it is supposed to. On my Ford CFI motor I spent years figuring out all the little things previous owners had done to get it to run well at normal operating temps (and fixing them). On my 914 I have found many ways to hide problems. CHT mods and leaks to hide rich conditions, retarding or advancing timing to address the idle issue your vacuum leak is causing, rerouted vacuum lines to address broken components, etc. Hell the car ran fine warm when I got it and it had three different injectors in it. That said, I am sure this is the AAR but it is good to know all of it is actually doing what it should be. As everyone has said, there is no feedback so it has to work like clockwork.

Posted by: wonkipop Dec 25 2021, 07:42 PM

all true.
but i don't have one of those cars thats been worked over and fooled with.
its purty much all ridgy didgy.
and mechanic and i confirmed all the sensors were fine 18 months ago.
its running absolutely original injectors (a full matching set of NOS off a guy in arizona 18 months ago, all bagged sealed from factory. its the same exact injectors that go in a beetle convertible). everything is schmick on that side of things.

what i do not have is a set of operating cooling flaps. admittedly.
and what i do reckon i have might be an AAV that there is no real test for, other than, is it open and does it close. which i did check. but thats pretty crude as a check.
what i have been searching for hard is finding out anything with a bit more detail on that AAV. there is nothing.

but what i do know now is it is officially an "emissions device".
admittedly an AECD, but one nonetheless.
which might explain why you just cannot get info on it.
its not meant to be adjusted or fooled with under the terms of the original emissions warranties (and as dictated by the EPA).
rather its meant to be thrown away and replaced at 50,000m or 5 years.

but of course we idiots are trying to keep these things going after half a century.



at least i know where i think i can find some of these AAVs easily in those SAABs.
it looks right. but i have to get one off and must make sure. elec connections etc.
i don't want to tear the one apart on my 914.
but i am happy to rip into some sacrificial ones if i can get hold of a few and experiment - assuming they will hook up ok. sometimes you get tripped up on the electrical connection or the hose size......but it sure looked like i was staring at a AAV that looked the same on the outside.

i did the same thing about 12 months ago when i bought a couple of old roller cell bosch fuel pumps from a VW guy in texas. i didn't care if they went. paid $20.00 for each of them. i wanted the parts and i wanted one as a tear down exercise before i ripped into two "good" pumps i had here (mine ran but leaked fuel). i managed to rebuild two original roller cell pumps that way. (motors were not worn out in them, all the seals were leaking). to fix the seals in a otherwise perfectly good old fuel pump you have to go all the way in and take them all apart.
its supposed to be impossible. it can be done. those old pumps are great because they deal with the hot location under the engine better than modern (in line or linear turbine) pumps. and i want to keep the pump where it was. call me a geek for doing that when everyone shifts them up front. but mine worked fine. i had no vaporization problems years ago. it was shifted just far enough in 74 to not get into too much trouble in original location. i also hate the idea of running high pressure fuel line through the cockpit (inside the car) which is what the 75 and later cars do! ?

as a result of that crazy exercise i managed to fix up two of the same type old pumps for my mates mercedes benzs. they were just leaking fuel, but fine otherwise.

Posted by: emerygt350 Dec 26 2021, 06:48 AM

My pump is still down there as well, not sure what I will do when I get steel lines. Probably go up front but I don't want to run the wires.

You may have better luck going to Saab for your AAR
I find the stock one in my car really annoying. You need it for the first couple minutes definitely but I wish it would just cut out after that even if it doesn't run perfectly for a little while yet. Instead it just keeps on going till everything is perfectly warm. I bet my heating element is weak and it needs the engine warmth to finish the job.

Posted by: Van B Dec 29 2021, 02:36 PM

Here’s an update on what I’ve got cooking:
I cleaned out eBay for original Bosch injectors. I’ve bought seven NOS 0280150112 injectors. I’ll send all of them out to get dynamic flow testing and see if I have four that can make a matched set. The other three I will sell on here. @http://www.914world.com/bbs2/index.php?showuser=10753 I see that you bought a couple recently so, if you want to complete a set let me know.
Also, I bought a new thermo time switch for a 924/944. The research I’ve done confirms that this part number also traces to the 912E. Not sure why nothing connects back to our 914, but I will compare them with a multimeter at various temps and see what we get.

Reasons for these endeavors are that I noticed a miss for a couple minutes after start on one of my recent attempts. My hypothesis is that if an injector is firing all Wonkipop (lol) then fuel could just be jetting onto the cylinder and not firing until temps get high enough to vaporize the fuel.

Further, I only get a couple of seconds of high idle when the engine starts which is almost certainly thanks to the CSV. So, maybe the thermo switch is not behaving correctly and telling the CSV to run for it’s max time of 20sec.

The test procedure for the 914 is closed below 68F or open above. However, the 912E manual gives varying levels of resistance at progressively warmer temps.

We’ll see if any of this bears fruit, but like I said before, I have no clear direction so it’s all trial and error from here.

Van

Posted by: StarBear Dec 29 2021, 03:09 PM

@http://www.914world.com/bbs2/index.php?showuser=8571 B Terrific; I have two pairs that seem the same but are different colors (maybe VW vs Bosch?). Will check and get back to you.

Posted by: Van B Dec 29 2021, 03:58 PM

@http://www.914world.com/bbs2/index.php?showuser=10753 look at the number on the side of the injector. It will be molded into the top half 90deg offset from the connector. As is so often the case, we can thank @http://www.914world.com/bbs2/index.php?showuser=104 for cataloging this info:
http://www.914world.com/bbs2/index.php?showtopic=78993&hl=neihoff

0280150112 is the factory injector. But there are three other injectors that are the same injector but with different hose options. Of those three, you would want to have 0280150116, the long hose you can trim to fit. The other two are short hoses.

Posted by: StarBear Dec 29 2021, 08:21 PM

@http://www.914world.com/bbs2/index.php?showuser=8571 B Here are the ones I have. The original in the car are 112 units, with a gray/beige connector. The two spares are also 112 units, but with a blueish connector. See photos.
Yes, would love another pair of tested, proven injectors as SOME time in the future my originals WILL fail. Awesome!
Current:
Spares:

Posted by: Van B Dec 29 2021, 09:38 PM

Yeah, connectors are beige but the injectors are blue-green. I noticed that on my car too.

Posted by: wonkipop Dec 30 2021, 03:16 AM

the old 68F, wonder where thats coming from hey?

@ Van - you can go for any one of the injector options on mr. b's website chart.
similar chart from a bus expert mr. r atwell. there are three counting the real ones.
think the other two are short and long hose. for bus and for 412/411 from memory.
we run the same ones as beetles from 79 or something like that. thats how i got a set, bought them off a guy in arizona who had them in his cupboard for years for his beetle.

then remove the incorrect hoses if you get the non exact injectors and buy a set of correct hoses from 914 rubber.
the hoses need to curve just right as they support the fuel rail. suspend it in mid air more or less.

Posted by: Van B Jan 2 2022, 03:26 PM

Where can I get a proper fuel filter for my car? I ordered the round Mahle filter from FCP Euro, but it looks pretty small. I haven’t pulled the tank yet so, I’m only guessing right now. But I figured I’d trust my instinct and ask you guys.

Posted by: wonkipop Jan 2 2022, 04:02 PM

you mean the little plastic cube ones?
i don't think you can get them any more.
also, i think the small mahle cylinder ones you get now might be better?

i've got one left in my box of ones i stockpiled 2 decades ago.
think i got them from Tweeks on west coast, out of business these days.

if you really want one a cube type (they do fit well into the clips off the body) you might be able to get them from a VW online parts shop. quality might be suss. chinese? look for old stock good stuff.

---

i fitted a high pressure cylindrical fuel filter after the pump in the engine bay.
main reason being i had to put a new pump in (for the moment).
original bosch roller cell pumps = a robust design. modern turbine pumps a different matter. i'm looking after the injectors i got given they are n l a.

my set up is the small cube in the gravity line near the pump under the engine bay.
and a much bigger high pressure filter in the engine bay mounted off the decel valve mounting plate. pretty sure it is a RAYCO. brand is hidden under the mounting clip.

this bosch one is very similar in size.
https://www.efihardware.com/products/291/fuel-injection-filter


edit
i took a look on cipi vw. they do have old style plastic cubes.
but no brand! have the advantage of going into the retaining clips.
if you still have your fuel pump under the engine bay.

my set up is probably overkill.
the old style one theoretically stops shit going in the pump.
and the big one stops the pump shitting itself into the injectors.

Posted by: Van B Jan 2 2022, 10:26 PM

I like the two filter idea. As long as I don’t restrict the pump, I think a pre and post filter would be good insurance. Like I said, I cleaned out eBay on original Bosch injectors so, just like you, want to make sure they last.

Posted by: Van B Jan 10 2022, 06:29 PM

Sorry folks, but this thread still lives.
I thought this would be a good time to post some updates:
The temp switch for a 944 is the wrong size and also, apparently is configured differently as a switch. After much searching, I ended up buying a thermo time switch for a Nissan/Datsun 280ZX. I thought to try this experiment as these parts are still in production and are cheaper than the superseded option on the Bosch/Porsche option. My next post will be about what I’ve learned on part numbers and options us lonesome L-Jet owners have.

Injectors all showed up, but one came with a broken tip. So, I’m working to get that resolved. Then I’ll be able to send them off for matching. I have high hopes for these injectors as I’m more convinced that something is up with fueling when cold.

Today I put the new thermo switch in the freezer for a bit, tested it, and then plugged it in the car for a test start. Before I forget to mention, my old switch tested bad. So, new switch checked out ok and when I went to start the car, it was hard to start (cranked for a bit). Once it fired, it came up for a solid 8 sec. but then it started to stumble and drag back down. I gave it some revs for several seconds, to about 1500 and the let it settle. When I did that, the car was running at a normal idle, not high idle, but a normal idle.

This change is a definite improvement. But now that we’re having some legit snow and ice weather, I’m getting true cold starts. And this stumble that has appeared certainly seems like an injector issue. I already explained my theory so I won’t recycle that topic. But at any rate, the thermo switch was another defective part removed and a step forward. Plus, we now know that a still in production Nissan part will work.

More to come,
Van

Posted by: StarBear Jan 12 2022, 12:31 PM

@http://www.914world.com/bbs2/index.php?showuser=8571 B = Yes, please do keep us updated. Interesting....

Posted by: wonkipop Jan 12 2022, 03:15 PM

" @http://www.914world.com/bbs2/index.php?showuser=8571 B"

i had to go google washington dc weather.
yep, that is a true cold start.
7-8 deg centrigrade colder in washington than n melbourne mid winter. your daily max = our daily min.

the cold start injector should, according to the manual, still do some squirting for a very brief time after the engine fires when temps are below 50F, not just on cranking.
so if your thermo switch was not working properly the csi might have been only activated while cranking. somewhere in material i have it says the thermo-switch can keep the csi activated for a maximum of 20 seconds (am guessing though that amount of time would be in super cold conditions near arctic levels of cold?).

thanks for the tip on datsun thermo switch. will see if i can get one down here for the box of spares.

Posted by: Van B Jan 12 2022, 08:20 PM

There he is!
Brother the weather here got stupid for several weeks and peaked with 30cm of snow over night and then stayed around freezing for a week lol. 8c was real nice after all that.
I’ve been here three years now and it seems like we get one of those a year… I miss Houston.

About the CSV, I looked back at my test video and it was only spraying while cranking. So, I missed that clue. But I also think the switch having continuity below 19.5c/68f is also telling the computer to enrich the mixture.

Anyway, here’s what I’ve learned about thermo switches for the L-Jet:

The ‘74 VW part number is 022906163. Later cars including the 912E got 043906163, which turned into 043906163A according to several online sources.

Abbreviated part number trail:
022906163 (VW) = 0280130202 (Bosch) > end/NLA

043906163 (VW) > 043906163A (VW) = 0280130214 (Bosch) > 92860510102 (Porsche) = F026T03100 (Bosch) = current/avail

The significant difference between the part families is that our original part was 19.5c for 8sec and the other family is a 35c for 8sec. I think Porsche just dropped the original as they evolved the L-Jet system to later emissions requirements; but that’s speculation.

Now, how I got to the Nissan Part was on a hunch thanks to @http://www.914world.com/bbs2/index.php?showuser=104 and his info about the licensing agreement from the Datsun days. Turns out Nissan still sells, via VDO license, the unaltered original part for a 280ZX as PN - 22635-N4711. As you can see from the photos, it is still made to the same spec as our now dead Bosch part at 19.5c/8sec. Further, it can be had for around $50-$75 less than the superseded Porsche/Bosch part depending on the sources available to you. As I described in my previous post I tested it and it works/fits just like the original.

The current Bosch is of a different built than the old style but I’m sure it’s still an option if you wanted to go that route as evidenced by the fact that mine had been replaced with a previous version from that family.

Van


Attached image(s)

Posted by: wonkipop Jan 12 2022, 10:28 PM

@http://www.914world.com/bbs2/index.php?showuser=8571 B

that sure is interesting with those temp numbers.

good old 19.5 celcius = that magic 68F that the EPA drew the line at?

whereas your 35C, man thats getting warm. the temp here today is 33C and its still going up. but out in the garage i would still consider that a "cold" start on the car left overnight. so would the more modern citroen and renault out there.

that datsun switch sounds kind of right.

most of the time the 914 fires up on about the second turn of the starter motor, - like pretty instant. which would be like 2-3 seconds of fuel from the csi while it cranks.
and unless its under 19.5C its not going to get much more is it? with an original thermo switch (and i'm pretty sure mine is original but still working, or was two years ago).
and most of the time down here except for three months of the year its over 19.5C.
so i reckon i'd be lucky to get more than 4-5 seconds of fuel out of the csi from the thermo and cranking in winter down here.

mine is starting fine though at moment. about 30 seconds of 700-750 rpm and then it climbs to steady 850-900. but its pretty warm right now and strangely humid.

Posted by: Van B Jan 12 2022, 11:40 PM

When my car is 10c or less, it takes several seconds of cranking before it fires… on occasion two attempts.
I have high hopes about this fuel injector swap

Posted by: wonkipop Jan 13 2022, 05:14 AM

you don't need to worry about your cold start injector over in western australia at the moment. (its a bit cooler here relatively speaking).

https://www.abc.net.au/news/2022-01-13/onslow-in-the-pilbara-equals-australias-hottest-day-on-record/100754082

Posted by: StarBear Jan 13 2022, 08:36 AM

@http://www.914world.com/bbs2/index.php?showuser=8571 B Thanks ever so much for your search and finding on the thermostat switch part. This thermo switch- where is it located? Is this the part that extends out from the oil sump cap underneath the car?

Posted by: wonkipop Jan 13 2022, 11:48 AM

right near the cold start injector steve. tucked under front intake manifold and vac hoses on rhs. if you want to get it out i think it helps to take the cold start injector off first. van will know for sure.

one on the sump is for your temp gauge in the console.
your special mate having a console.
we just have to guess we are cooking the engine.

Posted by: StarBear Jan 13 2022, 02:43 PM

Ahhhhh, THAT’S what that thing is. Always wondered. Thanks. Still learning!

Posted by: wonkipop Jan 14 2022, 07:55 PM

here you go @http://www.914world.com/bbs2/index.php?showuser=10753 .
i'd have sent this in a pm but i can't seem to do an attachment.

most cars it is screwed through engine block into a coolant passage.
takes on temp of the coolant.
this is where its shown in the diagram of L jet.

in ours, being aircooled its mounted it off a bracket just above engine block under the intake plenum runners. photo (from R Atwell) shows what you see if the plenum off.
screw it out of the bracket with a socket to remove. the c s i might be angled enough to get in the way. you might have to take that off first.

given it does not rest in engine coolant, that probably explains why it has different temp parameters compared to the datsun - a question for @http://www.914world.com/bbs2/index.php?showuser=8571 B ?

this little thing is one of the babies that controls the c s i. engine cranking is one but this is the other. it either keeps it going for longer than engine cranking and firing or shuts it off immediately, depending on its temp. its basically off completely above a certain temp. there is a bit of conflicting info out there on exactly what that temp is.
my understanding is its got a ideal time on it about 8 seconds at 50F and then gets progressively shorter all the way up to something like 90F but you know there are different versions in the tech lit you read. below 50F it goes the other way - up to around a max time of 20 seconds. (after that you are flooded?). its the time it takes for the electrically heated element in it reach the cut off from the ambient it starts at.

after your engine is hot, its sitting there at cut off so the most the csi does is a quick squirt while the engine cranks.

my experience when i was getting the car going again after its long sleep is that it does signal the c s i to squirt for somwhere between 5 and 10 seconds at around that 50F temp. all of my injectors were SNAFU despite cleaning but the engine fired up and ran for about 5 or so seconds. could only have been firing off the cold start valve. it was late autumn/early winter in melb aus in a cold work shop.

Posted by: emerygt350 Jan 14 2022, 08:49 PM

That is really interesting! 2.0's have the same thing and i have always wondered what was up with it. It looks just like a coolant sensor on my other waterbuffalos.

Yeah, what the cold start injector actually does is so shrouded in mystery and misinformation I am tempted to pull mine and just watch. I have read in some books it does nothing until you are below 50 and then it is just as the engine cranks, others the 20 second thing. All kinds of stuff. My engine does a really good cold start (even at 10F) so I assume it is working the way it should. I should put one of those current detectors on the wires and see what is doing and for how long. -10F tomorrow, too bad I am not near the garage this weekend.

Posted by: wonkipop Jan 14 2022, 09:31 PM

yeah, lots of different stories on it.

i take the factory manual to be reasonably accurate. it asks you to test it at 50F.
it should switch off after 11 seconds max. any longer and throw it away. obviously all a bit approximate as a rough test for workshop technicians, you know as if you are going to be standing around waiting for the shop temp to be 50.

lots of other stuff on L jets is for water cooled cars and have different cut off temps.
hence lots of differing info.

but the gist is the same with all.
its a graduating scale all about the time it takes to go from ambient up to the temp the internals heat to and ground the circuit. and if the little fella is already sitting there at that internal temp due to ambient engine heat its already grounded anyway.
but it doesn't necessarily stop the c s i giving a squirt during the cranking.
just like your old school carby car it still needs a little pump of the gas to start even in summer when its been left overnight.

and it is as dumb as being just a water cooled engine sensor.
bosch were running a component supermarket.
just tweaked the internal heated element.
all the rest of it stays the same for whatever car it was going on.
so the vw ones might be super tweaked. which is why i thought all of a sudden to ask van that question.

Posted by: Van B Jan 15 2022, 12:27 AM

Went and tested my new switch again since I haven’t permanently installed it yet.
21c/70f, nothing. Open circuit.
18c/65f, continuity.

The part that was in my car, 0280130214; and also broken, is not the correct part. It was a 35c switched used in all sorts of liquid cooled cars; BMW, DeLorean, SAAB, Porsche, etc.

Emery,
Many pages back, I took out the CSV and left it plugged in. I videoed it and it only sprayed while cranking. I didn’t think about it until recently, but it should have kept spraying for 8 sec after start. When I tried the new switch, guess what, 8 sec after start, then off.
I think the computer tells the CSV to spark when cranking just to help start, but only sprays for 8 sec when the switch says so. I’m also speculating that same signal may also tell the computer to richen the fuel mixture for warm up. The AAV circuit always activates for a set time to warm the heating element. But even if the element fails, the engine heat will heat the AAV and make the valve close.

Van

Posted by: Van B Jan 15 2022, 12:31 AM

Also, it’s so annoying that my name seems impossible to tag!
@http://www.914world.com/bbs2/index.php?showuser=8571 B
@“Van B”
“@http://www.914world.com/bbs2/index.php?showuser=8571 B”
@Van_B

Ugh….

Posted by: StarBear Jan 15 2022, 08:08 AM

Ok, maybe an interesting test this morning. Now 10F, “feels like” 0.

@http://www.914world.com/bbs2/index.php?showuser=8571 Yes, the tagging is quirky. Since no other “Van” users it picks that up and stops. Since other “Big” names I’ve not yet figured how to tag @Big Len or @Dr914_AutomobileAtlanta.

Posted by: emerygt350 Jan 15 2022, 09:10 AM

That always while cranking and 8 seconds when cold is what I suspected was the reality. I think Chilton says a much lower temperature than 65 but I can't remember exactly.

I can detect the enrichment with my afr gauge but it has been cold since I installed it...

Posted by: StarBear Jan 15 2022, 10:12 AM

Ok; here’s my morning test:
14F, “feels like” 3F. Sunny.
Used tach for rpm data.
Cranks to start: 7
Secs to start: 3
Initial idle 1100 rpm
1:30 idle 1300 rpm
2:00 idle 1050 rpm
3:00 idle. 950 rpm
4:30 idle. 900 rpm
5:30 idle. 950 rpm
6:30 idle. 1000 rpm
9:30 idle. 1000 rpm
10:30 idle. 1025 rpm
Steady at 1025-1050 after that.
All seems well in New Jersey….

Posted by: emerygt350 Jan 15 2022, 11:25 AM

That looks really good.

Posted by: Van B Jan 15 2022, 12:20 PM

That is a perfect result man! Your AAV closed when it was supposed to and even though the engine wasn’t quite fully warm yet, it looks like it got there in short order.

What is your tach error? Are you at 800-900 on the timing light?

Posted by: StarBear Jan 15 2022, 02:07 PM

Yep; spot on. Interpolated tach readings to the closest approx 25 rpm.

Posted by: Van B Jan 15 2022, 02:34 PM

Right but what is your actual tach error compared to a timing light?
Idle should be 800-900 RPM per the manual.
For reference, my tach looks to be optimistic by 50-100 RPM compared to the gun.

Posted by: wonkipop Jan 15 2022, 04:53 PM

nice work L jet-ters.

(i can't tag your name Van, tried all the variations, no go).

fantastic confirming the operation of the c s i van.

if it is 65F that it cuts off with an original and correct thermo-switch that is an exact match for the EPA definition of a permitted AECD. (aux emissions control device).
- devices allowed to work below 68F and above 86F for a limited amount of time to permit engine starting and initial warm up or prevent engine damage. this is one of the devices that triggered scrutiny by the EPA of the set ups in earlier D Jet cars from 72/73 MY and got VW into trouble - they had been using similar switches to permanently shut off the emissions equipment below 65F).

very interesting to look at StarBears numbers on cold start up.
mirrors mine - but higher.
3 minutes to 4/5 minutes is more or less what mine is doing, but its barely keeping going in my case. my warm idle is set lower at about 850 to 900. n my case its doing what StarBears does but at all times around 150-200 rpm lower. also StarBear has his cooling flaps hooked up so that is helping his and hindering mine (mine is disconnected).
its not doing it now, but its not winter.

i'm thinking maybe L jets staggering or subsiding after initial start up for a short time is an inbuilt historical feature. caused by the EPA ruling on that thermo switch and strict definitions of when and how the switch can work and what the car is allowed to do during warm up. normally its not so noticeable, but any one component out a bit and that stagger around the 3 minute mark gets very perceptible.

StarBears is likely working close to like its supposed to.



Van - my sense of what inputs cold enrichment is that it is the CHT and also the second sensor in the AFM (incoming air temp) and these input to the ECU to adjust how long the normal injectors stay open? you have a new CHT so that info should be good to the ECU.
the other one is more problematic in the AFM as i think its damn near impossible to replace if its not working right.

Posted by: wonkipop Jan 15 2022, 05:21 PM

apologies for not getting to mine and giving some input.

the last stages of falcon ute got in the way of the plans of mice and men.
(always takes more time than you think).
this thing had a hell hole that proves satan was only practising on 914s.

emery will like it? - being a ford/mustang man.
i didn't do the paint. the master (he who undoes my amateur operations on the 914) operated the paint bazooka. i will be permitted to weaponize on the inside of the pick up tub for target practice.

its a pity you don't live down here StarBear. I could have fixed your jacking plate for you.
i've got expensive rates but. would have cost you a six pack of yebisu.

Posted by: emerygt350 Jan 15 2022, 07:05 PM

Looking good! I just picked up a nice gravity feed sprayer for my efforts next spring. Been thinking about the gt350 quite a bit since the salt went down.

Posted by: wonkipop Jan 22 2022, 11:52 PM

@http://www.914world.com/bbs2/index.php?showuser=8571 B
@http://www.914world.com/bbs2/index.php?showuser=10753 .

in the interests of collective ability to be in different hemispheres and opposite seasons.

34C (about 93F) here today.
car started instantly.
did not even do the momentary quick revs.
no engagement of thermo switch on csi?

started at weakish idle of just at bottom of tach. 750-800 rpm.
but did not falter or go weak. just went slowly up from there.
after 4 minutes it was at 950 and steady.
felt so good about that had to go out for a quick
put a hat on and 50 plus sunscreen.
its lockdown quiet here again (without the dicktator locking us up).....all the folks are spooked by omicron.
----> led to great pleasure on empty city streets until i started feeling skin on my hands burning. gave up after 20 minutes and retreated to shade of my studio.

as i was pulling it in a rotund gent walked past and said - sh$t a nine one four.
man i've never seen one. can i have a look.
he was beside himself. looked about 65.

not like 30 years ago when i just got sneers.

Posted by: Van B Jan 23 2022, 01:31 AM

@http://www.914world.com/bbs2/index.php?showuser=10753 and I have our NOS injectors out getting tested. Once I get them back I’ll install the Nissan thermo switch, flush the fuel lines, new filters, and new injectors. I’m feeling cautiously optimistic that the switch and injectors are the solution. But, I’ve also been wrong every other time so, we’ll see. It’s been between-5c and 1c every day and for the next week or so. I’ll have amole cold start opportunities lol!

Sorry to hear that the brain washing has taken full hold down there but, at least there’s a silver lining to be found! Here in the DC area folks are drinking the kool aid too. It’s nice when I can get to the real America and see folks enjoying life.

Posted by: wonkipop Jan 23 2022, 03:52 AM

keep us posted on the results of endeavours.


unfortunately the UV levels are curbing my enthusiasm for rolling here.
i love the heat- its a dry heat....but this summer there is an incinerator pointed at you.
(tomorrow it goes tropical and humid!?).
UV levels from the BOM are off the hook.
put cracks in a 914 dashboard in 5 minutes that take a decade in california.

putting it down to lack of planes in the air.
i'm ready to beg the USAF to do some tree top fly overs of my neighbourhood with B52s and lay down some dirt trails in the atmosphere.

as a bonus there is a good opportunity to do some carpet bombing practice for the benefit of the free world.

Posted by: emerygt350 Jan 23 2022, 07:24 AM

Was -15 F here yesterday....

Posted by: StarBear Jan 23 2022, 08:34 AM

Balmy mid teens F lately here. No driving with residual road salt.
Nexteeek will pull it out and start cleaning up that repair patch. Got the jack triangle and doing some prep on the metal replacement patch.

Posted by: StarBear Jan 23 2022, 08:37 AM

Love driving up to the petrol stations and having the young kids screw their brains back in. The young fillies smile (sometimes) and wave when driving by. Have had two “older” gents ask me about it while at a stop light. None in the wild around here any more.

Posted by: emerygt350 Jan 23 2022, 09:07 AM

sigh. I don't think mine will see daylight until April...

Posted by: StarBear Jan 23 2022, 09:37 AM

@http://www.914world.com/bbs2/index.php?showuser=8571 Will be most interested in your thermo timer investigation. I can get one but a bit expensive as a maybe spare for a part not usually known to fail, though mine is the original nearly 50 year old part.

Posted by: Van B Jan 23 2022, 09:58 AM

You should check yours. Manual says put a multimeter on it below 68F and confirmation tone/continuity. If you get the beep, then you’re good.
I would be surprised if yours is still alive after that many heat cycles though.

Posted by: StarBear Jan 23 2022, 10:11 AM

A good cold Sunday garage task. Will report. Thanks!

Posted by: StarBear Jan 23 2022, 10:33 AM

@http://www.914world.com/bbs2/index.php?showuser=8571 My analyzer does have a continuity setting so used a mood light. Pulled connector wire and went from timer spade to wire. No light. Does ignition need to be on/running? Not the sharpest knife in this sort of drawer…..

Posted by: Van B Jan 23 2022, 10:37 AM

No. You just need to touch both prongs on the switch itself.

Posted by: StarBear Jan 23 2022, 11:00 AM

@http://www.914world.com/bbs2/index.php?showuser=8571 Oh, think I tested the wrong thing. Check the wiring diagram on Haynes page 177. It’s located UNDER the cold start valve which I must remove first (or just the blue CSV connector?)? I tested a sensor with a green/brown wire, near CSV next to distributor.

Posted by: StarBear Jan 23 2022, 11:16 AM

@http://www.914world.com/bbs2/index.php?showuser=8571 Removed blue connector. Noid light shows connectivity b/n the two prongs. Good to go. Might (?) still get that backup if your Nissan part test proves it works. I think (?) it should.

Posted by: Van B Jan 23 2022, 12:01 PM

@http://www.914world.com/bbs2/index.php?showuser=10753 the blue connector is the CSV. I don’t think you’ll be able to test the TTS without removing it. It’s buried in there.


Attached image(s)

Posted by: StarBear Jan 23 2022, 03:13 PM

We’ll, then the CSV has continuity at least. Yes, Haynes instructs to remove the CSV to get/remove the TTS. As cold start seems ok per last week’s test, maybe I’ll leave well enough alone. May order a spare once your Nissan part test checks out. Onward!

Posted by: Van B Jan 23 2022, 03:46 PM

I had to unplug the CSV and the TTS and then I was able to finagle a 24mm deep socket on the TTS.
But yeah, I agree with you unless your friends call you whiskers… ‘cause you’re curious like a cat lol!

Posted by: wonkipop Jan 31 2022, 02:59 AM

heres a new bit of esoteric trivia for you L jet die hards.

as mentioned previously and likely completely forgotten i hope -
mine suffers a peculiar little quirk in high summer here,
purely as a result of the modern fuel pump replacement i had to to do on recommission.

it hunts. the fuel is boiling and heating. cavitating in the pump.

well it was giving me this treatment sunday while i was trying to enjoy myself while being UV irradiated. at the lights up and down. up and down.
even threatening to die a couple of times. but valiantly coming back to life only to gasp again.
i had less than a quarter tank of juice left (in my reduced and amputated rhd fuel tank).
off to the petrol station to enjoy the pleasure of post lock down $2.00 a litre gas.
pumped in 20 bucks and got to half a tank.
drove out, got to first set of lights, still hunting.
gave it a bit and thought i'll just keep driving.
after 5 minutes the hunting was gone.

kept driving, kept grinning.
kept going for 1/2 an hour.
hunting gone.

got primitive brain into thinking mode and figured this out.
i've got a minimum volume of fuel, to keep fuel cool problem in high summer?
cause its circulating.
the whole fuel temp is rising as its pumped around through the pump and back to the tank.
below a certain volume of fuel the temp of the fuel rises to the point where its boiling just before and probably in the pump.
but get enough fuel going around and around and the fuel cools itself.

i need half a tank min in the car in summer to avoid the problem.

at least until i can get my rebuilt original pump back in which i think handles hot fuel and engine heat better.

Posted by: Van B Jan 31 2022, 08:22 AM

That is very interesting.
So return line dumps hot fuel into the tank and after a while fuel becomes hot enough that the low pressure moment within the pump causes boiling inside the pump or do you think it happens inside the fuel line?
Think about basic science class here, but I would think the 30psi system should effectively raise the boiling temp of the fuel.

Posted by: wonkipop Jan 31 2022, 02:40 PM

boiling in the line just before the pump.
(that runs across from tunnel to pump along rear cabin bulkhead)
and in the intake part of pump itself.
that fuel is gravity feed/pump suction - not much pressure.

not boiling in engine lines after pump.
but i'm getting fuel pressure drops as the pump fights to get fuel.

i also have a bend in the small section of hose line into the pump which i look at always and think - marginal.
works ok when its cooler.
that is probably the point where it boils.
won't solve that until i take the pump off and get the small original one back on.

with enough fuel in the tank i have discovered it seems to be able to cope.
volume of fuel in tank acts a bit like a heat exchanger and lowers temp of fuel enough that it does not boil at the critical section of line pre pump.

Posted by: Van B Jan 31 2022, 03:35 PM

For a time. As you describe, the longer you drive at temp, then the entire system would become heat soaked again and the problem would return. You either need to raise the boiling point of the fuel or you need to increase pressure on the low pressure/suction side so that you don’t induce low atmosphere boiling.

Luckily all this occurs well below flash point of the fuel; however, should a leak develop and the vapors find a spark, you will kaboom all the same.

I don’t think this is something I’d be comfortable managing. I’d want to solve this all permanent like.
But keep in mind this thread is all about a guy who can’t accept a mild inconvenience of poor cold start performance…

Van

Posted by: rhodyguy Jan 31 2022, 03:50 PM

It doesn't dump, it goes right back to the tank adjacent to the outlet spigot.

Posted by: wonkipop Jan 31 2022, 03:54 PM

the heat builds up in stop start driving.
don't know if you have noticed with yours how if the car is standing still hot air expelled from the engine collects in the right conditions up under the rear fender wells and also in the flank areas just in front of engine.

(this was the old fuel vaporization problem that 914s were famous for before they shifted the fuel pump to the front in 75).

summer down here is real hot. days are often still. no wind or breeze.
thats when i start to get the problem. no breeze to flush that bubble of hot air out.

winter is a different game.

i have carried a fire extinguisher in my 914 for 30 years.

you are obsessed with cold starts.
i have waking nightmares about fuel leaks.
check fuel lines like a kook with obsession syndrome before i go out for a drive.

its interesting, if the car stays on the move the problem never developes.
its just minor enough in stop start to cause the hunting, but never stops the car.

i think the mods to fuel tank come into play in my case as well.
a 1/4 of a tank is not the 1/4 of a tank that a lhd car has.
to do right hand drive you have to slice the bulb at the bottom of the tank in half and reduce the part that faces towards the cabin to get space for firewall mods for pedals.
once the fuel gets down to being in the bottom part of the tank there is not much in there.

sometimes i can starve it for fuel with a low tank and a bit of hard cornering in a long enough roundabout. but only when the tank is right down.
but its been a while since i could find an uncrowded roundabout without an SUV kook tiptoeing in front of me trying not to tip over.

I'm going to get into a bit of reflective insulation work on the metal fuel lines i installed as well when i put the rebuilt original fuel pump back in.
that may be part of the problem. the run of steel line across the back of the firewall to the pump.

they used to be plastic until two years ago.

it was pretty hot here on sunday. around 34C. but its hotter than that in the inner city where i am. asphalt and concrete. was easily over 100 in your F scale. it stood up to half an hour of good driving around with the tank more than half full.

Posted by: wonkipop Jan 31 2022, 04:15 PM

i know.

you just described the problem.
its a pretty small volume of fuel when my tank gets down (1/2 what you guys have in that bulb area). so i am circulating a volume thats just small enough to not lose enough heat on the way back there and in the tank.

but Van is right. it is dumping. the return line is being pushed by the pump.
pressure regulators and all. its returning under some pressure.
whereas the feed is a mixture of gravity and much weaker suction.
pumps push way stronger than they pull.
thats why the feed line is 2mm larger diam than return.
doesn't sound like much but it means the cross sectional area is at least twice as big as the cross section of the return. its done like that because of the physics of pumps.

Posted by: StarBear Jan 31 2022, 06:19 PM

Hmmmm…. I always keep my tank at half full or more anyway as I think it handles better and lessens chance of plugging the strainer sock. Another reason. Moved pump to the front a few years ago.

Posted by: Van B Feb 20 2022, 07:55 PM

Well friends, this weekend has been another weekend of trying to do a simple task only to discover another PO nightmare. So much on this car is all original, but more and more, I find that the work that has been performed was done half-ass and by idiots. So, imagine the work an idiot does at best and then divide by 2. What was meant to be a simple fuel filter change turned into a complete reorganization of the relocated fuel pump and filter to remove all the areas of pinched, twisted, and abrading hose. And replacing the vibration isolation bolts that were sheared because the cross clamping bolt was not installed in the fuel pump bracket.

But now that is all behind me, tomorrow I will be installing the TTS and injectors. Of the 7 NOS injectors purchased, 4 were fully fit for service. The other three flowed great, but had a terminal case of slanted spray pattern. Of the four good ones, they are perfectly matched. Ironically, tomorrow will be fantastic weather so, no cold start test. But I remain convinced, until proved a fool, that the injectors are the primary cause of the struggles on cold start. The secondary cause would be the failed TTS.

Hoping for success so I can close this thread and move on to more conventional 914 projects… like oil leaks and worn out suspension.

Stay tuned!

Posted by: StarBear Feb 20 2022, 08:07 PM

Best wishes, Van, and keeping my Fuchs crossed for you.....

Posted by: Van B Feb 20 2022, 09:15 PM

Thanks Steve!
@http://www.914world.com/bbs2/index.php?showuser=104 would you know where I can find the gasket or clip for the Bosch 2 pin connector?

Posted by: JeffBowlsby Feb 20 2022, 10:26 PM

Only available with a new connector housing.

Posted by: Van B Feb 20 2022, 10:42 PM

Copy, I suspected that might be the case. Thanks for the confirmation!

Posted by: Van B Feb 21 2022, 03:01 PM

Injectors are installed and have made a noticeable improvement to driving/running quality. Engine was out of time slightly again. I think my distributor clamp is not up to the task when I really wind the engine to redline.
Initial start up was obviously rough since the car had not run in a while and the fuel was drained. I’m concerned that I may not have solved the cold start as the engine reaily struggled until warm just like it has been. Once I got everything warm, starts are not problem, even when it was heat soaked from sitting there idling forever while adjusting the timing, it only cranked a couple seconds longer than a normal start.

It will get down to 9c tonight so, I’ll let the car sit outside and chill out lol… and then try a cold start again. This will be about the most ideal conditions I can give so, if it struggles again, I am completely out of ideas.

Posted by: emerygt350 Feb 21 2022, 03:12 PM

You should write a summary of what you did for each part of the cold start circuit and how you know each is up to snuff. Just for future folk with this issue.

Posted by: wonkipop Feb 21 2022, 04:14 PM

ah well.

wait and see.

still have not got to mine. nearing the end with the falcon but as usual i was over optimistic re time to finish it.

stacking up all my 914 components to hit it.
meanwhile, really enjoying driving it at the moment. weather is fine and sunny without being insanely hot and projecting death ray UV.

its running real nice apart from --------the same warm up weak knees as yours van.
but the good thing is while i have its arse stuck out of my roller door in the lane lots of old guys walk past on their way to the super market and i make their day --- apart from the old lady with her poodle that has a bow tie who makes a big scene every time holding her nose. its got me beat why she keeps taking the same short cut to do her shopping.
the poodle barks at the car like an extension of her personality.

look forward to your report.

Posted by: emerygt350 Feb 21 2022, 05:39 PM

This kind of knowledge storage is awesome, but a little scary. I wonder what will happen in the long run. Will this all be lost since it wasn't on paper ...

Posted by: wonkipop Feb 21 2022, 07:07 PM

i guess its here now on this website.
lasts as long as the website? which has been around for a while.
which ---is a kind of new book?

van's pursuit of cold start issues also provoked the dig into 74 1.8 L jets.
we kind of got to the bottom of it, for 74 at least, - thats in the history/originality section now.

certainly more here on this website than there is out there in the published paper world. ......and some of whats out there in books can be seen to be inaccurate information as time goes by and more detail surfaces. not the fault of those writers, they just did not have access to a broad enough sample of the cars out there to notice things or see much in things.

guess the L jet cars were in the shadow of the earlier D jets and also the concentration on the 2.0L 4s as the desirable variant?

EDIT
ps - thats why its worth $30 usd in fin. support a year.
not many technical subscriptions at that rate offering this kind of value for money?

Posted by: Van B Feb 21 2022, 09:12 PM

flum·moxed
/ˈfləməkst/
adjective
adjective: flummoxed
bewildered or perplexed.
"he became flummoxed when his 914 continued to struggle on cold weather starts”

So, tonight’s attempt required several seconds of cranking, then slowly lumbered to life at a very low RPM. It required two touches of throttle to keep it running in the first minute or so. But then it started to steadily climb out of the hole, which is a new behavior . I just don’t get it! I’ve only got another month of actual cold weather and so I really want to crack this!

So far this quest has uncovered a litany of issues; most of them attributable to improper maintenance. And most importantly, performance when warm has substantially improved. But I am convinced that the cold weather start struggle has multiple causes. Unfortunately, the only thing left for me now is to dig into the engine.

Posted by: wonkipop Feb 22 2022, 02:50 AM

there is only the AFM left to go?

it could be in there.

mine almost does what you describe.
but it does not struggle to life.
it springs into life (for about 10 seconds) and then subsides into the hole.
which it then digs itself out of as per yours.
it takes around two minutes to get up over the edge of the hole.

and then when its warm it runs just dandy.
as it always has.

apart from that hunting thing on a low tank of fuel.
but i am right hand drive which has its own unique problems of my own making.
but i have a full theory/explanation for that now which i shall go into after i reinstall my rebuilt original fuel pump and reroute a couple of fuel lines down there near the fuel pump.


starbear cleaned out his afm. he wrote me a pm about how it mortified him doing it.
he knows how to do it.
his does not seem to suffer this fall into a hole problem like ours?

Posted by: emerygt350 Feb 22 2022, 07:08 AM

Any of you 1.8people have an O2 sensor installed?

Posted by: StarBear Feb 22 2022, 07:57 AM

Not that I’m aware of, though after 48 years still learning about these little contraptions.

Posted by: wonkipop Feb 22 2022, 10:03 AM

no.

ie lamda sensor in the exhaust?

even the 75s with cats didn't have one.
no feed back loop in these early L jets.
they are called open systems.
don't think they went to closed loop L jet until very early 80s.


it does however take an input from the AFM at start up in two ways.
there is an air temp sensor in there.
and while the AAV is open its going to be drawing additional air and moving the AFM flap open slightly.

i figure that if the stamped circuit in the AFM is worn slightly or dirty right at that first part it could be affecting things. ie it gets extra fuel at start up by virtue of almost simple clockwork. aav is open, that pulls AFM flap open a small amount and signals to the ECU that the flap is open give it more fuel. and if its getting no air temp input properly that might be upsetting things too. ie no signal to the ECU that incoming air is cold. all its getting is a signal from the CHT - and its not enough? i'd have to think about it more.

its a possibility. van has been through everything else.
CHT, AAV, new injectors, he has done it all. timed it. tuned it.

once the car is warm it does not need that extra bit of air and fuel so it is content to idle through the idle port in the AFM? and does not need the extra air and flap open at all.
and you rarely (ie never) drive the car at 1200 revs so you never notice that bit of wear or dirt on the AFM?

a thought. can't think of anything else.
and mine is very similar.
everything is hunky dory when its warm.

Posted by: StarBear Feb 22 2022, 10:07 AM

“Everything is hunky-dory when it’s warm.” Kind of like us ‘mature’ folks, eh?

Posted by: emerygt350 Feb 22 2022, 12:28 PM

No, I mean for knowing your afr. I have one in my djet engine to help me tune it. If you had one you could see if it is a fuel ratio issue at cold start. Too rich? Too lean? Helps figure out what is going wrong.

Posted by: StarBear Feb 22 2022, 12:36 PM

We have a CO adjustment screw; that’s all though doubt many of us have a meter.
How does the O2 sensor provide a useful monitoring info? Ties into a meter reading somehow? An interesting idea….

Posted by: emerygt350 Feb 22 2022, 03:04 PM

Knowing it is too rich or too lean can point you to the issue (if it's fuel related). Also as the car warms and starts to run well you can see if the afr is changing appropriately. Just more data points.

Posted by: Van B Feb 22 2022, 03:08 PM

It would be a very handy diagnostic tool for sure. I don't want a gauge/dash setup but I would like to have one that could run as a stand alone with a probe or with a bosch wide band sensor. When I built the exhaust for my 996, I installed extra bungs just so I could have that option down the line. that car only has narrow band sensors so the data from them is not real helpful.

Regarding the 914 and @http://www.914world.com/bbs2/index.php?showuser=10753 's question, it would have much less usefulness for tuning and without another car with a confirmed functioning cold starting feature to compare against on the same day with the same temps, it would be tough to know what the numbers mean. I mean technically, I would see the values, but how much enrichment am I looking for, ya know?

Posted by: wonkipop Feb 22 2022, 04:49 PM

its way dumber than that @http://www.914world.com/bbs2/index.php?showuser=25740 .

you can adjust things after the engine is warm.
the CO screw does all that.
and you could additionally measure O levels with a probe.
but......may not help for the warm up.

from what i have read the warm up enrichment is controlled by 3 things.

1. CHT. Van has already put in a new one.

2. intake air temp sensor in AFM.

3. movement of the stator flap in the AFM (which would be drawn slightly open by the AAV being open).

#2 influences and modifies the signal sent by #3 to the ECU. so that intake air temp sensor has an effect on the signal generated by the stator flap and the ECU can recognise the engine is cold and even further to that it is drawing in cold air. logic tells me that is what sends it into the cold start regime. part of the input is the CHT. but there is also input to say stator flap is slightly open (AAV pulls it open but as a piece of "clockwork"). and the ECU recognises those two additional inputs, stator flap and cold intake air. ie it can also distinguish that the stator flap is open in a cold air situation. together all three switch a circuit(s)in the ECU that is the full cold start regime?

how you can adjust that alone is i think not possible.
you can adjust CO at warm idle and you can adjust CO generally i think at ECU further.
i'd have to check up on our ECUs for 1.8s again. but that is not going to help at warm up as its got an internal "routine" so to speak inbuilt in the ECU if you could call it that.

so i think an air temp sensor in AFM or the printed circuit the stator flap sweeps over could be a culprit. it would be in that section of the first part of the stator flaps movement. the open AAV would not be pulling the stator flap very far open at warm up.
but if its not getting the correct electrical signal generated by that first part of the AAV flap movement it is definitely going to affect enrichment. it might be worn or have residue built up on it.

there is some proceedure to clean that printed circuit in there.
i've come across it here on this website.
how to open up the AFM and do that.

as to the temp sensor in there.
somewhere i have an L jet tech manual that tells you how to test it.
but.....having said that it then says that if it is defective it cannot be repaired.
however - as we know 914 owners seem to be capable of rebuilding just about anything at this stage that previously were regarded as unfixable and to be thrown away.

------

down at the workshop i can get hold of an exhaust gas analyser.
a real old piece of equipment. we use it to tune all the old cars.
but there is something that needs fixing on it at present.
we have been borrowing one from the mechanics across the road.

i'd have to leave the 14 down there overnight and then do a cold start fire up.
i think that would give me the values you are talking about emery?
whats going on at cold start in terms of the air fuel ratio.


-------

i've got a good CHT i have tested.
i've got good injectors that work perfectly.
i've got a good cold start injector and temp switch that works perfectly.
i've got an AAR that opens but i suspect may close too quick.

and a similar set of symptoms to vans car at cold start.
and a similar set of components i know to be close to as good as the ones van has in now.
(i'm guessing if i was in maryland or cold cold north america mine would really fall in a deep hole too for the first couple of minutes just like vans).

and i'm think with mine when i get it into the workshop for the fuel pump fiddle that i will see if i can do the tests on the AFR and maybe even open it up and clean it if necessary.
i can test the temp sensor too, but what i can do about it i don't know if its not right.

Posted by: emerygt350 Feb 22 2022, 06:23 PM

Well, something is up. Knowing couldn't hurt. Pretty much every car wants the same thing as they warm. 10:1 at the start (csv) rapidly leaning to about 12:1 (cht) then a slower rise to 14:1 (at idle). I know at idle wide bands are not great but in both my 84 FI mustang and the 2.0 914 they follow the same pattern. Both run about as good as they can (the mustang probably better than it was ever meant to).

Posted by: emerygt350 Feb 22 2022, 06:28 PM

Temp sensors can be tricked with pots and resistors...

Posted by: wonkipop Feb 22 2022, 06:34 PM

good general info - thanks for that emery.
i'll try and get mine on a machine with the exhaust probe and see if i can get some comparative measures. got to get the ford falcon out of the way to make room to leave it down the workshop. not far to go.
it will be a bit cooler here soon in autumn so i can get a better guage on cold starts again.

Posted by: Van B Feb 22 2022, 07:22 PM

Manual doesn’t tell me what pins to check for temp sensor 1. The 912E also isn’t helpful because it’s a 7 pin connector.

Posted by: Van B Feb 22 2022, 08:41 PM

Without the tester specified in the manual, there are only two resistance checks I can do, and I don’t even know what they mean. But I do know that mine is within spec on both readings.


Attached thumbnail(s)

Posted by: wonkipop Feb 22 2022, 09:07 PM

try this.
its from another L jet manual i have.
unfortunately there is no real separate test it seems for temp sensor 1 distinguishing from potentiometer test. both are same?

Posted by: wonkipop Feb 22 2022, 09:10 PM

looks like your info is same as mine.

if you tested it and it is ok that is good news.
means your temp sensor 1 is still ok.

it could be the worn track thing on the inside.
i need to find that thread here about cleaning it.

i'm sure starbear told me he did open his up and this cleaning proceedure.

Posted by: Van B Feb 22 2022, 09:23 PM

I pulled the cover and it’s nearly new in there. It’s a rebuilt unit from fuel injection corp.

I mean it, I cannot think of any other system aspect to check. The only roads left are mechanical.
It’s not like I haven’t made steps through all this by finding and addressing substantial issues, but nothing has solved the cold start issue.

Posted by: Van B Feb 22 2022, 09:32 PM

I would say these are the numbers of a well tuned engine. I think OE tunes are generally a bit too rich (high 12’s)

Posted by: wonkipop Feb 22 2022, 09:45 PM

is the flap moving freely in the intake plenum chamber.
can you sense any hesitancy from the closed position.

just wondering it if could be sticking and the aav is unable to pull it open at cold start.

sticking with the idea that what triggers the a f r mix is the air flow in L jet.
(yes there is temp input, but its in parallel with the flap being moved).
i mean that is all i can see that triggers the enrichment for cold start up.
those two sensors and what must naturally occur if the AAV opens which is the flap moves in the air flow meter to let in additional air or send the signal that additional air is coming in. if its not getting the signal that additional air is coming in then temp sensor 1 can do all it likes to modify the signal but the signal would be saying no add air is incoming.

or am i thinking this wrong?

Posted by: wonkipop Feb 22 2022, 10:07 PM

am thinking there is one last test you can do.

it should be possible to undo the aircleaner, get the base out of the way and prop the top half so you can see inside to the flap. do a cold start and go have a look and see if its pulling the afm flap open during that first initial part of warm up.

sit there and watch it. see if the AAV is doing its job and pulling that AFM flap open.
and watch to see if it closes right up again when its warm. it should since by then it will be running off the idle passage through the AFM. to my way of thinking it cannot be doing initial warm up through the idle passage alone?

this should not disturb anything or cause any air leaks.
and its the last mechanical test of all components.

if that flap is puling open then its got to be something not getting that signal through to the ECU. or in the ECU itself? because you have crossed everything else off the list?
as far as i can tell anyway!

i admire your commitment to the cold start.

Posted by: Van B Feb 22 2022, 10:54 PM

It moves like it’s made of butter. But I don’t see any reason not to lay eyes on it during a start up.

My commitment to this is that I believe a real cold start brings out issues with an engine that may otherwise be masked in more favorable conditions. That’s how the “cold start” became such a classic proof when selling or buying a car.

Just look at all I’ve uncovered during this pursuit:

-Spark plugs that weren’t seated
-Faulty fuel injector
-Incorrect engine timing
-Incorrect setting on decel valve
-Bad thermo time switch
-bad voltage regulator
-wrong charcoal filter pellets (leaking into the intake)
-cracked intake boot
-cracked vacuum lines
-pinched and twisted fuel hoses

And since I still have this cold start issue, I know there are more problems to discover.

I’m just tired of striking out. I can’t really say I’ve enjoyed my 914 ownership so far… especially when I have this beast of a 996 sitting next to it that is always ready to party!

Posted by: wonkipop Feb 23 2022, 01:06 AM

joy of a vintage car van.
its half a century old, and you have sorted out a ton of dickskull mechanical work done by others and general decline reversed.

i've got a little renault RS clio i can take out anytime and its always up for a party.
as per your 996. mines a wolf in sheep clothing. cops don't even look twice at it.

but the steering feel will never equal the 914.
esp since i stuck the 165s on the 14.

i'll put up with the warm up in mine if i can't solve it.
sounds like i might hit the same brick wall as you.



PS - the other way to look at it is that L jet is such a heroic bit of wartime style engineering that it can keep the engine going even though some component is letting it down. like a machine gun full of dirt that just keeps on firing.
rather than seeing it as a fault its like something that just won't give up even in old age.

i'll use emery's handy figures on what to look for roughly on a f r by sticking a probe up its tail pipe on a cold start and see what happens. i figure if the a f r is ok when its all warm and operating normally then its not suffering any damage during normal use.

its important not to be tempted to put too much boot into it when its cold via the accelerator as you can get a backfire and that will do the AFM no good at all.
its a balancing act to get it up to temp and oil circulating but also avoid the back fire.
mid 70s 911s used to be famous for blowing up their airbox and doing all sorts of damage on a cold backfire even down here in emission free (relatively speaking) australia in the easy going "she'll be right" era long past. i think they ran K jet. but i don't really know. 911s have always been outside my budget. and now they are so outside it they are in another universe. but a mate of mine has one. a 75. had it since new. he never sells any of his cars. he has some technique or mod to his airbox so it blows the hose off before it blows anything else up. i think its as dumb as not having a hose clamp done up too tight. only he is allowed to do up the hose clamp.

Posted by: wonkipop Feb 23 2022, 07:47 PM

this is of interest van.

in 5 parts.
guy with an l-jet opel manta tuning the afm.


https://www.youtube.com/watch?v=PqEBgS6hSGQ

Posted by: StarBear Feb 23 2022, 08:49 PM

Posted by: Van B Feb 23 2022, 10:47 PM

Yeah, I’ve seen those videos. Would love to have those tools!

Posted by: wonkipop Feb 24 2022, 12:39 AM

yeah i want his a f r machine.
have to keep my eye out on ebay.
was especially into the way it had CO arrayed at bottom as well.
it had it all in a nice little box.

we have got a much bigger version and just as analogue down the workshop.
it looks like it dates from the 1970s.
but there is something wrong with it that needs fixing.

Posted by: Van B Feb 24 2022, 09:18 AM

A weird thing happened last night. I went out to start the car, mostly out of boredom and frustration... and after cranking a few times it fired up and jumped to 1400 RPM! As I sat there in existential confusion, it slowly climbed to 2000 RPM. At that point I got a little concerned and blipped the throttle and the car cut out and died.
So, like a good little monkey, I started the car again. Same result. That's when I realized I never plugged in the 6-pin on the AFM after testing it the day before. So, I plugged it back in and started the car once more. This time it started and went to a normal idle. No doubt the resulting normal third start was due to the fact that it was warm out and the car had already warmed up sufficiently.

What I'm struggling with now is that this happy little accident has seemingly ruled out a mechanical fault. I mean other than taking more cranks than what most people report as the norm, when it started with the AFM unplugged, it behaved just like my 996 for the first few seconds... a smooth high idle.

@http://www.914world.com/bbs2/index.php?showuser=24231 @http://www.914world.com/bbs2/index.php?showuser=10753 would either or both of you be willing to replicate this experiment for me on a cold start to act as a control? In other words, would you unplug your AFM and attempt a cold start and let me know what happens? I would like to know whether this behavior is atypical or if it's standard.

Van

Posted by: emerygt350 Feb 24 2022, 10:56 AM

Very interesting!

Posted by: Van B Feb 24 2022, 11:18 AM

To put it mildly.
I plan to mess with the points settings tonight and see if that changes anything. From reading the manual, .4mm is the start setting, and .3mm is the minimum. I don't have a fancy dwell machine, but I think I'll move the points gap in and out and see what changes... if anything.

Posted by: rjames Feb 24 2022, 12:21 PM

They aren’t that fancy. Don’t guess at the setting. You should be able to find a dwell meter for ~$20.

Posted by: emerygt350 Feb 24 2022, 12:29 PM

I have an ancient dwell meter from back in the 80s when I had an opel. Critical equipment. My opel wasn't that sensitive to point misadjustment but the 914 was super sensitive. So sensitive that the 123dizzy was a god send...

Posted by: StarBear Feb 24 2022, 12:44 PM

@http://www.914world.com/bbs2/index.php?showuser=8571 will do and let you know.
Yes, get a dwell meter. I find mine is very sensitive.
EDIT: Spec is 44-50 degrees; I get mine right on 48 though takes several attempts even starting with gap tool.

Posted by: Van B Feb 24 2022, 01:00 PM

My math runs like this:
Pertronix > points+dwell meter

I placed an order for the Pertronix Ignitor III with built in rev limiter. In this way I can remove points from the equation entirely.

I don't see enough info on the L-Jet out there for me to pull the trigger on the 123ignition just yet.

Posted by: emerygt350 Feb 24 2022, 02:33 PM

As long as the points go, you should be better off.

Funny thing on these engines is the rev limiter is kinda useless. It's the overrun that will blow your motor.

Posted by: Van B Feb 24 2022, 02:36 PM

you mean the ole full throttle 4th to 3rd? That should be near impossible on a bolt action shifter like the 914 lol!!

Posted by: StarBear Feb 24 2022, 04:00 PM

A lot of us 1.8s have had trouble getting Petronix to work; others no problem.

Posted by: StarBear Feb 24 2022, 04:57 PM

@http://www.914world.com/bbs2/index.php?showuser=8571 B didn’t get hone till late and snow/ice tonight and tomorrow so might not get to it until Saturday or Sunday. If I recall in the past, when I did the same it just cranked and never turned over (informing me I had not reconnected it).

Posted by: wonkipop Feb 24 2022, 05:10 PM

wow, yours started with the 6 pin out.
i already know what happened with mine once.
i changed my air filter out and forgot to plug it in.
no start.

i can try again later when i have a moment and see what happens to double check that.

Posted by: wonkipop Feb 24 2022, 05:14 PM

right on.
that rev limiter rotor was/is a waste of time.

fyck up a gear shift and bye bye engine despite the stoopid rotor.

Posted by: wonkipop Feb 24 2022, 05:39 PM

@http://www.914world.com/bbs2/index.php?showuser=8571 B

those you tube videos with AFM - you can see the little track i was talking about.
with the sweeper.

people sometimes go in and make sure the track is super clean and also adjust the sweeper very slightly so it runs in a different spot.
it can wear a groove as years go by.

however i don't think this would be affecting warm up idle.
but maybe if the first section of track is a little worn its possible.
be right at the start of the track.
that is one of the connections between the flap and the ECU that is important to the ECU knowing where the flapper really is and how much air is coming in.

------

Posted by: Van B Feb 24 2022, 05:57 PM

Like I said earlier, I pulled the top off and everything looks new in there… brand new. It’s a rebuilt unit from Fuel Injection Corp.

And yeah it started but any touch of throttle would kill it. So, clearly fuel injectors are commanded to send fuel even without the AFM. But there was no way for the computer to adjust fuel.
What was really bizarre was the high idle and that it jumped right to it from a first start.

If y’all can at least try it, it would be much appreciated.

Posted by: wonkipop Feb 24 2022, 06:09 PM

i'll give it a shot later.
have to get the renault out of the way.

will report back when i have done it.

Posted by: wonkipop Feb 24 2022, 07:26 PM

ok

i just did it.

it started.
straight away like it does connected.
one crank and bang it went.

i touched nothing like i usually do.

did not go to high revs.
was at about 850 rpms.
then stopped on its own after about 10 seconds.
never got higher than 850.

i reckon it ran off the cold start injector.
reminded me of the time when we recommissioned it and the same thing happened.
fired straight up, ran for 10 seconds then stopped.

so i don't believe i was getting an injector signal when i just did that.

i remember now when i last did the disconnect thing accidently.
it fired up and then stopped.

i reconnected it.
did a normal (ie abnormal) start.
ie it went weak for that first 2 minutes and then came on.
but it needed that plug in for the regular injectors to be signalled to fire.


so--------this is gettng real interesting now.

Posted by: Van B Feb 24 2022, 07:36 PM

So mine ran for several minutes without the AFM plugged in. It definitely was not the cold start injector that kept it going. That thing can’t put out enough fuel to support 2k RPM.
But it is interesting you didn’t get a fast idle… I’ll see what results Steve gets. I don’t yet know if this is a thread I can pull on or not. But I can’t get past the fact this is the first time the car did not struggle on cold start.

Posted by: emerygt350 Feb 24 2022, 07:37 PM

Wow, I think you guys are on to something! No idea what but this definitely looks like a worthy lead.

Posted by: wonkipop Feb 24 2022, 07:37 PM

after reading one of your posts a few back where you mentioned the 912E manual you were looking at, i searched that up.

came across something i thought was interesting.
they really changed the characteristics of the cold start injector and thermo switch on the L jet 912 2L.






its currently 19.8C right now in melbourne.
maybe its a little cooler in the garage.
but its definitely not 13C out there.
and it definitely ran off the cold start injector for sure when i fired it just then and nothing else. but who is to say that info there is strictly correct from that manual.

point is i found it interesting that they really beefed up the cold start for the 912E.

Posted by: wonkipop Feb 24 2022, 07:42 PM

yeah no way it was the cold start injector.
yours ran.

and that is very different.

Posted by: wonkipop Feb 24 2022, 08:00 PM

well we know you have a good strong set of new components in yours van.

van.

cht.
injectors.
afm rebuilt.
everything checked. aav. cold start. thermoswitch etc.

wonki.
injectors is all that is new.
the rest of mine is just checked. (2 years ago).
i have an afm i reckon that has never been opened.
no evidence. i have never opened it. had it for 30 odd years.
doubt it was ever opened before i got it.
i could have had a component deteriorate since 2 years ago.
and will recheck all shortly once falcon is out of the way. cht. aav etc.

its possible mine might run like yours but something stopped it since the engine was cold. a now defective cht? hard to know. ie something did not indicate to the injectors to fire more fuel than when warm. so not continueing to run or go to high revs could be down to that. and it merely mimicked the stuffed injector scenario of 2 years ago.

definitely only wanted to go for that 10 seconds and cold injector would have let it do that then not enough fuel to persist beyond that.

be interesting to see what steve's does.

-----

alternatively there is some scenario with yours where it is firing the injectors and that is not normal.

i'd have to do some more reading again to work out what signals the injectors when its all proper.

Posted by: wonkipop Feb 24 2022, 08:32 PM

ok you got me thinking.

there is a variation on this exercise i should do.
warm start it with the plug off.

that will tell me if i am getting some kind of injector signal which does open the injectors to run the engine or not to cross check against what happened to yours.

if it does the same trick of not running then i know i do not get injector signal for sure with the plug off.

Posted by: Van B Feb 24 2022, 09:07 PM

Regarding your 912E reference, that is entirely determined by the thermo-time switch. Essentially, what that manual says references a TTS that is NLA.

You can see here that my old dead switch was a 35c switch (912E). The new Nissan switch is 19.5c. But both are still 8sec.


Attached image(s)

Posted by: Van B Feb 24 2022, 09:11 PM

I hope so. Wonki is a research monster so, I definitely need that right now. I can’t believe how there’s just no info on all this after 48yrs of 1.8L 914’s on the road.

Posted by: wonkipop Feb 24 2022, 10:00 PM

yeah van

but what i have been thinking is that 1.8 L jets were burdened with a marginal right on the edge warm up from the start.

that just worked. right on the edge.

reason i say that is all that EPA stuff i stumbled across on EC-A/EC-B research.

i think the EPA monstered VW into a warm up procedure that turned off these thermo switches at anything over that 68-65 F temp that was the low end of the EPA test range.

there is slightly varying info on the 914 1.8 cold start thermo switch.
but i think the general gist is its fully operational at under 55 for the full 10 or 8 seconds and from 55 to 65/68 it operates increasingly shorter time until at 68 theoretically its off.
but mine certainly worked this morning. but maybe it was cool enough in garage to be down there for it to flow for a good 5 seconds and dump enough fuel for the motor to run for about 10.

then a couple of years later i think the EPA relented and let porsche/VW have a thermo switch that was activating for cold starts above 65/68 F test temp so long as they could prove it was a cold start only and operated only for a max 10 seconds.

i think that is a really big change on the 912E. for fundamentally the same motor and EFI system. its a way bigger margin the cold start works in temp wise and i bet it dumps in a whole lot more fuel during that period it activates.

....and they must have wanted to make that change for a reason.?


i think they were really getting leaned on by the EPA.
right about the time the poor 1.8 was being worked out.

i think everything working fine and when brand new it warms up.
buts it right on the edge.
and it maybe never really did the kind of warm up we get in more modern cars.

the vac retard is pulling the timing back.
the aav has to work perfectly.
if your timing is out by a bit, or your points clagged or gap wrong.
the wiring is degenerating etc.
and then its got zero safety margin and starts to get frail trying to make the motor run cold.

reason i say this is everything settles down fine on mine once its managed to get warm.

i'm really trying to remember what mine was like 30 years ago.
i don't think it was as weak as it is now, but i don't really recall a time when it fast idled up really strongly from cold.

what we need is an old timer like the late cap'n krusty with a vivid recall to tell us what they were like just out of the showroom. but all those old timers are passing away.

i'm still thinking my aav is some kind of problem.
and i am going to rig up the garden tap gizmo that emery has to test with.

but this thing where your car ran without the plug has me really thinking.

Posted by: wonkipop Feb 24 2022, 10:34 PM

re those thermo switches.

the temp rating means at that temp on them they work for whatever it is.
8-10 seconds. its a certified measure.

as current warms them up or engine heat warms them up they reach a cut off temp that closes them. the cut off temp is not the temp inscribed on the switch.

they take time to reach that cut off temp as well.

i'm betting the 914 works approx like this.
at 55 its on for approx 10 seconds.
and by 65 (or 68) its off.
and it takes about 8 seconds to get to that cut off.

that kind of spec would meet the crazy demands of the EPA in 73.
68F was the temp the EPA was obsessed with.
anything could switch on under that temp for a cold start, but above that temp they saw it as outside "the law" when they cracked down.

VW used 65 F to give themselves a safety margin on EPA edicts.

meaning - start your car at 60 and it fires for about half that time. say 4 seconds.

and below 55 it can theoretically fire for even longer because its going to take longer to hit 65. hence references you find to it operating for anything up to 20 seconds max.

once the electricity hits it it will reach 65 and cut off no matter what, from a really cold temp even well below 55 by about 20 seconds later.

thats my take.

but then they come along with the 912 and they want it to work at a higher temp for that 8 seconds. which means it must fire for longer when its down at that lower temp of say 55? and the EPA must have relented and said, yes you can have that, its only on for 10 seconds, we will allow it, it cannot operate as cheat device, etc.

or is my logic out here?

whatever it is they wanted more fuel dumped in the 912 for longer and at even higher ambient temps to get it going.

------

i might be a research monster but i can only find stuff experts have written.
and there is sweet F A out there on these early L jets covering this particular problem.

it seems 928s suffered a bit from something similar.
and there is discussion in forums about symptoms not unlike this with ours.

i need to find out more about 928s of which i know zero.
i think they have an AFM and not a mass flow meter like late 70s 911s.
but i don't really know.

i do know that 964s have an AFM with flapper just like ours.
porsche reverted with those.
it didn't work too well i believe as they like blowing up their AFMs from stories i have heard. bit of a big backfire and its all over in there.

Posted by: djway Feb 24 2022, 10:54 PM

If you are starting without the pin hooked up you should be running solely on existing fuel pressure as your pump shouldn't work.

Posted by: Van B Feb 25 2022, 12:23 AM

I would’ve said the same thing prior to this, but it ran for a good while. At 2k RPM mind you.

@http://www.914world.com/bbs2/index.php?showuser=24231
I can attest that when the thermo time switch is above the rated temp, the circuit is open. As for it ever allowing the CSV to run longer than it’s rated 8sec. I doubt it. But, it would be testable.

As for my current status, technically, I haven’t ruled out a temp sensor 1 issue. As the two resistance tests in the manual only say to test between pin 6 & 9, and 7 & 8 with no explanation as to what those readings are confirming. I think I will call fuel injection corp and ask them.

Further, the way the engine ran when the AFM was unplugged had no stumbling or anything like that. It was smooth and consistent. Which means, I need to drop the theory on a mechanical fault.

For now, I just need to think about what just happened and understand if it is an exception or if other 1.8’s do the same.

Posted by: wonkipop Feb 25 2022, 01:39 AM

re running without the pin hooked up and fuel pump.

mine had been sitting since last sunday.
it was friday today when i did the pin out test for van.

i dunno, i think the fuel pressure would have subsided in the lines.
but i don't know.

the pump shuts its valves and i suppose there is pressure in the circuit.
it maybe does maintain just enough after 5 days bleeding down.

its an interesting point you make djway.

i could have used up all the residual pressure in the line when i did the plugless start.

i did not think to do it twice. that would have demonstrating something.
i am a dummy.

should have tried it a second time with the plug out after it quit.
would have answered that one.

i can try again on the weekend.

Posted by: wonkipop Feb 25 2022, 01:50 AM

thats interesting.
because its saying at rated temp, its on for 8 seconds.

and it needs electricity to warm it.
which isn't going to be instantaneous is it?
and that mechanism is internal to it.
its not unlike an AAV?

its like it goes on at 13C, keeps the CSI open and shuts off the CSI as soon as it warms it to the cut off temp. which must be a little bit higher?
and at that little bit higher temp when its warmed by ambient or engine block temp it never switches on because its open.

i always thought the thing about their factory manual test at 50F (or whatever it is exactly) is to time the CSI squirting is just a kind of standard to see it worked and to time it working at that spec temp.

anyway i could have been running off residual fuel pressure today,
or i could have been running off the CSI even though it wasn't below 13C.
or i could have had fuel pressure and injectors firing but set for warm engine with no other information and it just gave up.

i'll give it another shot from cold with the plug out and give it a second turn of the key after it dies. i'll try and listen to the pump as well for you in all the chaos. with the pin out theoretically it will not be running (even if i crank?). anyway i should have bled off all fuel pressure today in the test i did for you van. so tomorrow might be interesting.
that will tell us at least whether it was just residual fuel pressure and we can settle that question mark for you van. (unless for some reason the fuel pump goes when you crank but switches off unless the AFM plug tells it to keep going?).

can't wait for steve's test.

Posted by: StarBear Feb 25 2022, 08:24 AM

Still snowy, icy and sleet here today. Possibly tomorrow; maybe Sunday before I can push it out of the garage to test.

Posted by: Van B Feb 25 2022, 10:15 AM

No worries! I appreciate the assist!

Posted by: wonkipop Feb 25 2022, 08:08 PM

ok @http://www.914world.com/bbs2/index.php?showuser=8571 B

and @http://www.914world.com/bbs2/index.php?showuser=19266 .

i had to sleep on this fuel pump working thing.

schematically it is true that the stator flap runs the fuel pump once the engine has started. but.
that is when its above idle.
or below full throttle.

the fuel pump will not be run by the AFM until the AFM takes over.
the AFM takes over when the stator flap opens a small set amount and closes the fuel pump contact. this causes the stator flap to take over operating the fuel pump.

that occurs after the throttle is opened - to move the stator flap - and to move the throttle switch off the idle position - which switches off the throttle switch controlling the fuel pump.

the stator flap can only move (once the engine has warmed and the AAV has closed) if the throttle is opened.

its an on off throttle switch in the L jet cars. its only on at idle and at full throttle.
in between the throttle switch shuts off and does not control fuel supply (ie the fuel pump). the stator flap takes over in between. this works in reverse when you deaccelerate and close the throttle. the stator closes and stops supplying the fuel pump with power to operate, and the throttle switch takes over again and supplies signal for idle fuel metering.

i am fairly sure i have this right.
theoretically a 1.8 can run at idle without the stator flap controlling the fuel pump and the fuel pump will run at least.

to me that says it is possible for van's car to run as it did.

you can also look at it from the AFM flap end of things.
if the car is warm and the aav is closed the stator flap should be closed?
the idle air is drawn in via the idle by pass passage without moving the stator flap.
i believe this is the case. the stator flap is not being deflected when the car is at stable warm idle.
if the stator flap does not move the fuel pump contact does not close.
its impossible for the fuel pump to be operated by the AFM at normal warm idle.
its operated by something else at warm idle.
the throttle switch?

they basically pass the batten once you open the throttle.

now as to why vans ran and mine spluttered to a halt.
i'm not sure.

all his components are in fine form.
maybe that was enough to get it to run.

who knows with mine.
things could have deteriorated over the last 2 years since i woke it up.
aav might not be working so well again.
cht might have gone down hill since bringing it back to life.
i haven't tuned it for 12 months but its still running just fine.

i could do a second test on mine i think which may be more informative.
which is to warm it fully up.
take the cold start out of the equation.
and see if it will start itself and continue to run at idle with the AFM pin pulled out.


---

this is all tied in with the so called safety circuit.
which is designed to stop the fuel pump after an accident if the ignition is still on.
i'm still trying to get my head around that.
somehow once the engine stops it must all switch off even if the ignition is on.
but i don't really understand that bit yet.

but the fuel pump works
1) when the engine is cranked. pressurises the sytem.
which may still have some residual pressure in it that it can hold for some time depending on the state of the regulator, the fuel pump back flow valve etc.
2) when the AFM tells it to work as it opens.
3) by something else when its at idle because it ain't the AFM.

Posted by: wonkipop Feb 25 2022, 10:28 PM

test 2 for you @http://www.914world.com/bbs2/index.php?showuser=8571 B

light pictorial relief of lab conditions.
late summer.
28.5 C
slob australian youth glued to hi phone providing background context so you know its not faked from a location in the northern hemisphere.



warmed it up fully.

now i know my fuel system retains pressure beautifully.
i rarely start it 2 days in a row.
didn't even crank. exploded into life at turn of the key.

pulled switch.

cranked.
ran for i estimate 3 seconds.

cranked again.
struggled and tried to run and got to about 5 seconds maybe 6.

cranked third time.
repeat of 1.

cranked fourth time.
repeat of 1.

mine will not run with the plug out. even warmed.

conclude yesterday it did indeed run off the squirt from the cold start injector for the 10 seconds it went.

could not hear fuel pump during test crank and brief run.
doesn't mean it wasn't running. just could not detect it from where i stood cranking.

mysteries of 914.
might read up again on just how that pump is running in the idle mode.

Posted by: Van B Feb 25 2022, 10:54 PM

Thanks @http://www.914world.com/bbs2/index.php?showuser=24231 love the pic too! Kinda captured an impressionist moment there.

Anyway, your test is what I would’ve expected. I appreciate you doing that. We’ll see what @http://www.914world.com/bbs2/index.php?showuser=10753 gets. This isn’t just a fuel pump running, but also injectors are firing in time…. I just can’t understand this car!

Posted by: wonkipop Feb 25 2022, 11:29 PM

was interested myself in how the fuel pump runs at idle.
would have been nice to have detected it going if it was.
impossible to get my stoopid head under car without ramps or something.

interesting that it did fire.
injectors must have fired? even briefly/weakly.
wouldn't have been anything else. was well and truly warmed up.

least i know my csi works.
what made it run for sure yesterday.
it ran strongly at 850 for those 10 seconds.

today it was a barely go situation for the 5 seconds max it tried to run.

Posted by: djway Feb 26 2022, 12:37 AM

AFM needed to close the circuit.
You probably ran on stored pressure without any pump.

Posted by: wonkipop Feb 26 2022, 01:05 AM

which means the stator flap is moved at idle.
maybe not opened to air flow but sucked by engine vacuum a small amount - enough to close the contact and run the fuel pump?

which means that van's fuel pump has been wired to run un-commanded by the stator flap. only way his could have run?

Posted by: Van B Feb 26 2022, 09:25 AM

That is another thing to check for sure. But It’s a secondary target. The question I want to answer is not how did it run? Rather, I want to to know why it ran the way that it did?

Since the fuel pump runs with or without the AFM plugged in, then it cancels out of the equation.

Posted by: wonkipop Feb 26 2022, 09:44 AM

true.

i think its a separate problem from the warm up problem, which remains similar in profile to mine.

yours ran without the afm connected because -
it ran off the throttle switch in the idle position.
the only way it could have? and it got fuel.

i got my head around the AFM.
its not an arc inside like i pictured it.
more like a rotary engine combustion chamber.
at idle the engine vacuum is enough to pull the stator flap in the first pure arc to operate the fuel pump but not admit additional combustion air.
the warm idle fuel amount is controlled by the throttle switch, not the AFM in that region?
thats what i can work out.

though there is a little bit of conflicting information on that in the manual that implies the idle position on the throttle switch is not used. but elsewhere it says it is.
having to read and re read this stuff.

the aav happily sucked the stator flap well open to let the additional air in without the computer knowing about it?
it kind of went half mechanical in a way?
mixing that air that it didn't know was coming in with the fuel it was happily supplying.

the errant fuel pump let it do it?

so, it doesn't really get us any closer to whats the warm up hole our engines fall into.

-------

emery can likely explain why it ran the way it did precisely.
but factors could be something like this.
cht told the computer it was stone cold? so whatever idle switch normally wanted for fuel it got more because it was stone cold?
aav closing slowly changes amount of air but let a lot in to start.
engine warms up a bit as it proceeds changing combustion chamber conditions.
fuel condensation etc.
engine speed rises on its own because aav is acting like a kind of throttle in relation to rising engine temp. and it kind of does a little runaway?......for a while.

and ------ whatever fuel it got from the throttle switch position with an input from the cht was more than it would have got from the aav sucking the stator flap open and the afm controlling the warm up when its plugged in? why it started at 1400. that amount of fuel and that amount of air let it run at 1400 from cold. and for a while the two graphs of diminishing air and rising temp kept the fuel mix in the zone for it to sit at 1400 rpm.

i can't think of anything else that would explain it.

Posted by: StarBear Feb 26 2022, 01:16 PM

Ok folks, here are my results. Day at about 35F:
Test 1- sitting for 2-3 weeks, started on sixth crank with no throttle. Ran about 10 secs at wavering idle of 850-1000 rpm. Died.
Test 2- Waited 30 secs. Started on second crank and ran for 30 secs first at 850-1000 rpm then crept up to 1500 rpm before died.
Test 3- Waited 30 secs. Started on second crank and ran for 40 secs first at 1000 rpm then crept up to 1800-2000 rpm then died.
Weird behavior, eh? Neither of ours show the same action. Somewhat similar but not the same. Temp? Barometer? Magic?
At least they start and winter hasn’t killed the battery so getting ready for actual driving!

Posted by: Van B Feb 26 2022, 03:46 PM

@http://www.914world.com/bbs2/index.php?showuser=10753 @http://www.914world.com/bbs2/index.php?showuser=24231
This is very informative! So, setting aside the likely theory that when my fuel pump was moved it was wired to pull from a different 12v source, your test confirms that they will start and go to an abnormally high idle without the AFM. And, importantly, yours ran longer and at a faster rpm than the cold start injector could support meaning the injectors are functional without the AFM.

Today has been another day of mystery for me. My timing was still a little off from my previous experiments, but when I cold started the car today, other than needing 4-5 revolutions before firing, it had proper cold start behavior!

Before I attempted the start, I took the points out and discovered that the washer on the screw was split in two pieces and that the points action was a little sticky. So I replaced the washer, sanded the points lightly to make them a little more parallel, ran a bunch of WD-40 through the lever arm, and then re-gapped them to .38mm.

After a few cranks, the car started, went to 1400RPM just like it did without the AFM, but didn’t climb higher this time. After a couple minutes, it fell to around 1000RPM and stayed there. I let it keep running until fully warm and found that the timing and air screw both needed to be adjusted.

I went for a short drive (rolled 53k miles btw) and the car definitely likes .38mm vs the .4mm I had previously. But I was also wondering how that broken washer may have been effecting the points? I started to think it had allowed the points to move or something.

I’m also wondering if starting without the AFM had reset something in the computer? What I need now is repeatability. So, I’ll let the car get cold again and hopefully get another chance for a cold start and another in the morning.

I suppose I can investigate the fuel pump 12v wire in the meantime…

Thanks guys!

Van

Posted by: StarBear Feb 26 2022, 04:05 PM

Posted by: emerygt350 Feb 26 2022, 04:18 PM

That sounds like a good start! I would not be surprised if that points issue was causing issues.

Posted by: Van B Feb 26 2022, 04:59 PM

@http://www.914world.com/bbs2/index.php?showuser=25740
Me either. That would bring the total of main contributing causes to three:
-Malfunctioning injectors causing a dead cylinder on cold starts
-Bad TTS not providing signal for full fuel from CSV
-Points drift or binding on cold start

Honorable mentions would be:
-incorrect spark plugs not seating
-multiple vac leaks (lines and intake boots)


But I have yet to see if what happened today is repeatable so, I won’t allow any optimism just yet lol…

Posted by: wonkipop Feb 26 2022, 05:40 PM

f-en weird.

i did not try repeated cranks on mine cold - test 1.
might redo test 1.

though starbears is very similar to mine on the first time it started - about 10 seconds.
sb's would have taken those six cranks to build fuel pressure from cranking as it had been sitting a while? the running for 10 seconds bit is exactly like mine.
i just didn't do the repeated cranks after 30 seconds - so who knows, mine might do that from cold. wouldn't do it warm though.

i was going to ask you van if your fuel pump had been moved.

steve - has your fuel pump been moved up front.

mine is in original spot.
but is a new fuel pump - turbine two port.
but i don't believe we rewired anything.

Posted by: wonkipop Feb 26 2022, 06:00 PM

it sounds like you might have cracked it with yours van.


steve's could not have run for 30-40 seconds with residual fuel pressure could it?
thats a bit long or is it possible?

wonder if you did some kind of equal to a reboot van.
i remember we had to do it all the time with our old 486 computers back in the 90s.
residual errant voltages etc. electricity.

its a funny zone it operates in at cold start is what i now realise.
the afm is definitely being operated by the stator flap with the aav open?
and at the same time the throttle has the idle switch on in that position.
- in some way they are interacting? or handing off to each other?

all of our cars were definitely getting injector commands off the throttle switch?
the test showed they were the same in that way.
how long they ran had something to do with state of tune, fuel pressure/or not, state of info coming in from cht etc but nothing from the afm.

Posted by: StarBear Feb 26 2022, 06:13 PM

Yes, moved mine to the front a few years ago. A trusted mechanic so doubt it was wired differently.

Posted by: wonkipop Feb 26 2022, 06:20 PM

van should be able to spot his.
if its running off the ignition circuit source only, it will be running with the key on.
be the same for you. if its in a spot where you can easily listen for it you can run that little test.

mine definitely does not run with the key in the on position before i crank.
so i know its working like it originally was supposed to.
its in fact right under me with my right hand drive.
i can hear it easily when its working hard on a hot day.

and thinking about it, you have a lot more fuel volume at that pressure that takes longer to bleed off? might explain why it could run for a bit longer - but not sure about that.
emery might have a better idea.

i sure do not have that volume of fuel at full pressure to bleed off. just the injector circuit and short line from the pump.

Posted by: wonkipop Feb 26 2022, 06:45 PM

yeah the six cranks at the start make sense with the f p up the front.
takes a lot longer to build the pressure in that long circuit than mine.
mine is pretty instant. not suprising with original f p location.

i could not believe how it started yesterday.
bang. i honestly did not even hear the starter motor it was so instant.

Posted by: Van B Feb 26 2022, 07:13 PM

I honestly can’t understand the point of the OE three port fuel pump. It was such a chore to sort out the mess of lines that the PO left for me to deal with. I can’t believe a couple of them hadn’t rubbed through between the pressure against a sharp metal edge and the broken mounts for the fuel pump.

Posted by: wonkipop Feb 26 2022, 07:46 PM

they make sense in the original location.
all the fuel lines come into one end of it and don't do any vicious curves.

i had to put an inline turbine pump in. which is
a) longer
b) has a line in each end.
i have that pump in the original location.

thats why i am having that little hunting problem on real hot days and the low fuel tank.
the curve i had to do with the hose into the top (inlet) is just tight enough despite the care i tried to take getting it all in, that the fuel after a while is heating enough to boil at that curve before the pump causing the pump to cavitate. also the fuel has to travel about 4-6 inches higher up in the air than it does with the 3 ports down at the bottom of the pump. given its gravity feed from the tank it all adds up enough to disturb things on warm enough days. whereas the old pump never suffered from vapor lock despite the rep. the pump in 74 was jammed right up in the furthest right hand corner of engine bay.

Posted by: Van B Feb 26 2022, 07:54 PM

Yeah the mounting location is still there on mine. First time I saw it I was confused. I plan to ditch the three port and put the Bosch pump you have. Then I can run the return line straight from the firewall to the tank. A pump with a little more gusto would be good considering it’s up front now.

Posted by: wonkipop Feb 26 2022, 07:55 PM

re having three ports.

the mercs had the same thing but the pressure relief port was internalised.
and so it was hidden.
from the same era they look like two ports but the pressure relief valve is inside as part of the housing under the other end of motor. so it just reliefs backwards into the supply line.

vw and others used the three port to pressure relief back into the tank return line.
i think this was a alternative for a design engineering situation where you wanted all your lines coming in at one end of pump in a tighter space. made the pump itself more compact in terms of the motor housing length and grouped all lines at one end.

i managed to rebuild two of these pumps.
my original one and one out of a 74 saab.
both have barely any wear on the motor brushes bits.
they were just leaking from all the dried out o ring seals.
mine's going back in when i tackle all this business you have been investigating van.

Posted by: Van B Feb 26 2022, 09:09 PM

Well… I’m not out of the woods yet fellas. I just tried another cold start after letting it chill in the garage for several hours. It took 5-6 cranks and then it fired up. But this time it went to a low sort of idle after the 8sec of CSV ended. Stable but low. Definitely improved but not like it was earlier today. I touched the TTS and engine case to make sure they were cold enough to activate that cycle and I’m confident they were. So, I’ll think about it tonight and try again in the morning.

Posted by: wonkipop Feb 26 2022, 10:08 PM

something to be aware of is you are/will be running high pressure line through the cabin.
is it still the original clear plastic line?
if it is its pretty old by now.
you would want the steel lines in.

thats part of the reason i decided to stay with the fuel pump in original location.
i don't have high pressure through the cabin.
but i did renew the plastic lines and made my own out of mild steel tube.
the ss kits won't work for right hand drive at the top end near the front firewall.

when the factory went to front fuel pump in 75 they changed the plastic lines through the cabin to a different type of plastic. for high pressure.

back in the cowboy days of front fuel pump updates it always was on my mind that folks were running high pressure through a clear plastic line that was originally designed for low pressure gravity feed.

they seemed to get away with it. but.............

Posted by: wonkipop Feb 26 2022, 10:10 PM

damn.

i want you to crack this ---for purely selfish reasons i admit.

Posted by: Van B Feb 26 2022, 10:46 PM

I haven’t pulled up the carpet, but I know I have flexible plastic tubes coming our the rear firewall and stainless steel lines, coming out the front under the tank.
Don’t know if that’s stock or not.

Posted by: emerygt350 Feb 26 2022, 11:35 PM

Yeah, stock.

Posted by: wonkipop Feb 27 2022, 12:08 AM

......and ready to burn with 35lbs of healthy pressure testing them out.

Posted by: wonkipop Feb 27 2022, 12:13 AM

Posted by: wonkipop Feb 27 2022, 12:17 AM

oh yeah.

just been for a nice drive in mine.
pulling out afm plugs didn't re-arrange any electrons in the jurassic brain box.
same old stumble into a hole cold start.
but if did do the bam start thing.

drove fine after warm. still grinning.

Posted by: wonkipop Feb 28 2022, 02:07 AM

@http://www.914world.com/bbs2/index.php?showuser=8571 B

i sat down with mike today at lunchtime and asked him to explain to me exactly how its working at cold idle and warm idle and how do you diagnose the cause of the weak cold start.


first thing to do.

this is a cold start test.

disassemble air cleaner - prop up or hold the afm section so you can see into it and operate it.

you will need someone to sit in the car and start it.

after it uses up the cold start injector fuel, push on the stator flap in. gently but a bit more and a bit more.

if revs increase, say to 1200 or a more.
there is enough air, but its too lean under warm up. (ie you just gave it some more fuel for the same amount of air) it can only pull it through the aav.

if revs decrease or it dies.
its got enough fuel but its not getting enough air under warm up. the aav is no good.

thats step one.


i asked him about the stator flap being open at warm idle.
he told me to do the same thing and look inside it with a torch and see for myself.

Posted by: wonkipop Feb 28 2022, 02:32 AM

........and he had a view on why your cars ran.

steve. you better check yours. its 99% sure to be set up like vans.
they would have just found a source off the ignition circuit.

its not that big a deal. but it does mean your fuel pump won't switch off after an accident with the engine stopped but the ignition still on.

Posted by: StarBear Feb 28 2022, 07:37 AM

Thanks for the tip. I’ll check it out.

Posted by: Van B Feb 28 2022, 08:20 AM

So, I do not hear my fuel pump running when the ignition is switched on. But I have located the 12v wire as being routed to the bottom of the relay board. Next I need to determine what it's plugging into.

I've also decided to replace my alternator. Even with the improvements made, I'm still getting a "G" light on startup and have to give a little dab of throttle for it to go out. yesterday I put a multimeter on the battery after a cold start and gave it throttle from the engine bay so I could see what was happening.
Keep in mind I spent $200 on a fancy and near impossible to find Bosch Solid State regulator in a previous attempt to solve the issue. What the multimeter revealed is that I'm lingering at 12-ish volts after start (raw batt voltage), when I give a light dab of throttle, it slowly starts to build voltage over about a minute; 13.1, 13.5, and then settles at 13.98v.

I don't think I can confidently assess ignition health on cold start with an issue like this in the background so, I have a Bosch reman alternator on the way.

Posted by: Van B Feb 28 2022, 08:37 AM

@http://www.914world.com/bbs2/index.php?showuser=24231
I certainly appreciate you recruiting your mechanic into the conversation. After I get the alternator in, and before I do any further experimentation with the distributor/ignition, I'll give this a try. Spring is near so, I'm going to be running out of truly cold mornings in a month or so. Normally, I would be firmly excited about that, but my lack of resolution has me a bit frustrated.

I bought this AFM on the samba:
https://www.thesamba.com/vw/classifieds/detail.php?id=2399180
Now that it's sold, the other pictures are gone, but it is a NOS of a Bosch reman; which Bosch doesn't do anymore. Best case, this will help me confirm a temp sensor 1 issue; worst case, it's busted from years in storage and will need another rebuild in order to give me a viable spare.

Posted by: wonkipop Feb 28 2022, 04:14 PM

@http://www.914world.com/bbs2/index.php?showuser=8571 B

this is pretty interesting.





http://www.itinerant-air-cooled.com/viewtopic.php?t=7761

Posted by: wonkipop Feb 28 2022, 05:06 PM

mike was telling me about the AFM on 964s yesterday.
porsche reverted to stator flap AFMs on those cars.
he said that the printed track can get a lot of wear around the idle position from years of doing city traffic. that can upset things with those cars.

again - i have not opened my AFM up. that can wait for time and space in the workshop.
edged the falcon that bit closer yesterday. i'm discovering that finishing the final touches on reassembly takes about 3 times the amount of hours you think it does.
especially when you hit small hitches correcting things broken on the car and cobbled together over its life in the previous 25 years. morning consumed by a tail light lens yesterday.

----

re alternators.
most will struggle with output if engine is below 750/800 rpm.
its a kind of a catch 22 situation? - for the alternator if the engine doesn't jump to a strong start. or is there some other subtlety here you can explain to me so i can go looking for that when the time comes.

------

be interested to hear confirmation on fuel pump running or not with ignition on.
because unless that stator flap is controlling it there is no way it should run and for there to be fuel pressure. depending on the fuel pump they can run pretty quiet. my orig three ports were pretty quiet when i bench tested them running kerosine through them.


.

Posted by: StarBear Feb 28 2022, 05:08 PM

Opened up and cleaned my AFM a few years ago and again last Spring. No too dirty but did do the eraser thing on the tracks and tweaked the contacts a bit to new material but not very much.

Posted by: wonkipop Feb 28 2022, 05:45 PM

steve, apparently thats not the best way to do that tracking adjustment.
or did you move the plate itself and not bend the arm contact.

what mike told me yesterday.
and also that itinerant article i posted link to.
you have to very careful with that little arm.

having said that, looks like it worked ok when you did it.


----

there was a bit more conversation from mike yesterday.
i didn't include that.
which was.....if you were getting fuel its entirely possible for L jet to run like yours did with the afm unplugged.
for want of a better word there is a kind of limp mode or base line in the ecu that will make the engine go. but it wants to look for input or receive input.
so once it starts running and some inputs come in, like from the CHT, it will go outside parameters without the afm inputs and then just stops at that point.

it was not a detailed conversation. he just said. yes it would go, but it would not take too long before it stopped itself.

i don't know enough and did not press the conversation.
but that thing where yours started strong at 1200 rpm might be how the engine first fires up. off the CHT input. and i guess then the AFM is supposed to send some info too.
but that baseline sure sounds like some basic cold start parameters with a CHT temp input. as if the engine uses that to first start as a baseline which the afm then inputs into with its information. ie confirms it? and off it goes after that with the afm controlling things regarding mixture off the aav. that baseline start would assume a certain air volume into the intake through the AAV opening? but you can think too much into that.

Posted by: Van B Feb 28 2022, 06:55 PM

Wonki, those write ups you linked to will be great reference material. I had learned all the AFM stuff from my 944 back in college and even tuned on it a bit back then. But, I’m going to need to source an exhaust gas analyzer. Leaning these engines too much can make them run hotter than you want in certain conditions.

I found a Heathkit exhaust analyzer on eBay that looks real cool. But I don’t know if I should go that route or a more modern wide band sensor that can be used on my 996 as well.
First world problems… I could be getting shelled in the Ukraine right now I suppose.

Posted by: emerygt350 Feb 28 2022, 07:16 PM

I have recently bought a couple different brands of wideband. Expensive and a cheaper AEM. The AEM is fine. You used to find those for just a tick over 100 in the US. I have found a nice cheap combo where you can buy a 50 Bosch wideband that works with a more expensive gauge that isn't that expensive if you don't buy it with their 110 dollar O2 sensor. If you go that route I can give you the part numbers.

And if you don't want to run wires you can do what I did...



It actually worked really well.

Posted by: wonkipop Feb 28 2022, 07:40 PM

indeed. would not be nice getting putinized.

its good you are of the era fooling with 944s. puts you in a good spot.

my post uni days were screwing around with a twin carb squareback.
erwin rommel era tech.

then i just had cars that ran trouble free for years and didn't need to do much engine diagnostics. even now the renault keeps powering along just fine and its a 2002.
just do cam belts, engine mounts stuff like that. the electronics sides of its been just fine on its own (touch wood).

so i'll be moving into some territory with the 14 soon - maybe - that is a bit new for me.
why all this is of interest. if it turns out to be the case that mine is suffering a similar malaise.

love emery's rear view gauge. thats suave and sensible.

Posted by: Van B Feb 28 2022, 08:18 PM

@http://www.914world.com/bbs2/index.php?showuser=25740
That’s actually pretty clever… you should call it your RVM-HUD, rear view mirror heads up display!

Ouch… I think I pulled a muscle trying to make that joke funny….

Anyway, I’m actually more worried about finding weldable metal on my original exhaust with regard to a wide band port. That shit is barely hanging in there and I need it to last until I’m ready for that project.

We can’t all be like wonkipop and dine with veteran Porsche mechanics on a Sunday afternoon lol!

Posted by: wonkipop Feb 28 2022, 09:04 PM

don't get the wrong idea.
mike is way younger than me.
i'm 61. he would be barely 40.
was apprentice of the year back in around 2000.
apparently his special gift was 928s.
he could fettle them naturally, when a lot of guys in the shop he worked in just walked away from them.

he likes big cars, big mercs to be precise. the bigger the better.

my mate max, an old architect has a big collection of cars he amassed over the years,
has never sold anything.

max made an arrangement with mike to look after his cars, run a little workshop etc and mike has flexible hours to be a modern dad and fit in around his high powered wife's career.

its limited customer entry into the workshop. mostly what comes in are cars that bigger shops around town have either given up on, or refused to work on.

some very new stuff surprisingly. and plenty of old stuff. porsches. alfas. quite a few citroens. the mechanics for those are dying out and giving up. and he works on a few old school holdens etc. very eclectic. oh, and the other speciality is original wankel engines, not mazda. he looks after an nsu R080 and a citroen GS birotor. the GS is uber rare. there is only one in aus these days. it comes to the shop every now and then.
a very frail and fickle creature that car.

yesterday was monday. not a relaxing cafe latte set breakfast.
an hour off at the lebanese bakery from fixing the falcon.
and assisting mike to extract the radiator out of a c-6 citroen in between.
boy......what a job that was. most of the front had to come off. french!

i just his pick his mind.
2 years ago when we were bringing the 914 back to life i ran and fetched things and paid attention to him.

earlier he had helped a mate and i do the head gasket job on a citroen xm V6.
with the engine still in the car. supposed to be impossible. we did it.
proved its not an engine out job.

during covid dictator lockdowns i kept him company in workshop and tackled the falcon alongside an merc reconstruction he had to do. bonus for me - he has taught me how to do rust repairs. got a handle on most of it except the welder. got to get more practice on that. i am ashamed since my father was a boiler maker.

so ------ its the reverse of a usual "apprenticeship" working under mike.
i'm older. and i take instruction from a younger master.

he kind of won't really answer questions unless you show a half grasp.
then he tells you where you are wrong, but won't complete the picture.
i'm guessing that is how he was taught and he is reproducing the method.
"don't tell em too much or they will jump ahead too far and get it wrong".

anyway do his afm flap test and post results.
it will pretty much tell you if the aav is still some kind of culprit.
not that you can really fix them --- it seems.

and he didn't say anything about if its the other alternative.
but i'm guessing he would once that test is done and eliminated.

i just go in to the workshop on mondays. i day a week.
once the falcon goes out the door the 914 can come in and sit in a corner for a while as we muck around with it. your R + D will sure come in handy i think.

Posted by: Van B Mar 10 2022, 11:33 PM

Would be great if these guys posted up the resolution to the problems they were having:

http://www.914world.com/bbs2/index.php?showtopic=355672&hl=

http://www.914world.com/bbs2/index.php?showtopic=356316&hl=

@http://www.914world.com/bbs2/index.php?showuser=8358
@http://www.914world.com/bbs2/index.php?showuser=991

Posted by: Van B Mar 17 2022, 07:35 PM

Time for a little update for the three of you that are still following my quest lol!
I did the alternator change only to learn that the voltage light was due to the solid state Bosch VR not kicking in until some output threshold was reached. Which means that 48yr old alternator was not dead yet (sorry old fella).

Once I finished the alternator, I slapped the AFM on to try the test recommended by Wonki’s friend, Mike. The revs dropped when I pushed on the flap. So, I took the AAV out and started probing on it again.

But, while I had things apart something caught my eye that sent me on a whole other quest. I noticed that the port on the airbox from the charcoal canister was roughly the same size as the ports on the Aux Air Valve (AAV) hook-ups. But, the canister hose was larger. I then dug in the box of take-off parts and found the “original” I replaced on the AAV shortly after buying the car.

See the date stamp on my AAV is from ‘96. But because of the aging on the hoses, I thought they were original. So, when I replaced the hoses, I just got the same size I took off. But they were way too small and must’ve been replaced decades ago which made them appear as weathered as the other original hoses. I had installed 10mm vs 12&13mm hoses which was choking the AAV circuit.

I put everything back together with some 1/2” (12.7mm) hose this time and gave the car another start the following day. The weather has been nice, which is unfortunately bad for testing cold start behavior. But I think I observed a marked improvement in the first couple minutes of running. Idle still drops low, but not to the point of death like it would before.

Posted by: wonkipop Mar 17 2022, 07:48 PM

well i don't have any hose mix up issues with mine.
and have the same warm up issue.

so the mike test says its the aav.
we have almost come full circle.

the whole way along i have mentioned this time to time to him,
he raises his eyebrows and says aav.

getting a bigger hose on would certainly help a bit with an aav that has chain smoked 2 packets of marlboro a day since it was 12 years old and is sitting in a wheel chair wheezing.

good work.
sounds like part way to an answer.
your 96 aav is probably in better shape than my invalid unit.

i've managed to convince my mate to let me have that aav i found on his old saab.
he finally realised that car is good to no-one. even him.
we are trying to figure out what else to strip off it before it goes to the great swedish sauna in the sky. his other saab donated an entire D jet system to a lancia he owns and he thinks ahead to situations where you say --- damn, i swear i saw one of those on that piece of crap i had crushed.

Posted by: Van B Mar 17 2022, 07:54 PM

My little update is growing, are you all impressed?!

After the shenanigans above, I took off the distributor and installed the Pertronix Ignitor II, new plug wires, new plugs one step up on the heat range (NGK-BP7ES), and then retimed.
I was too advance by 3-4 degrees to make any judgement on how it started then, but I definitely liked the response from that ignitor and how rock steady the timing mark stays when I hold the timing light on it.

Lastly, I pulled the trigger on this guy just for the sake of thoroughness and follow through on the results of the AFM test.
https://www.summitracing.com/parts/smp-ac358

Standard motor calls it the AC-358, but what showed up was unquestionably Bosch!
There is another version, the AC-361 that I would be curious to see what actual Bosch part it is too, but I’m not buying another one just for the hell of it.

Below is a side by side of the original part number and this potential replacement. Observations so far are that they are physically identical on the exterior. However, the valve inside is quite different. The new one is a different shape and is composite material vs metal. Given it was meant for a BMW with twice the displacement, I expect it to flow more, which is what I want!

I’ve decided that I’m going to start a thread for L-Jet people on all the non-standard replacement parts we’ve found that are available to keep thee L-Jets alive… I’m now running a Nissan thermo-time switch and maybe soon a BMW AAV after all.



Attached image(s)

Posted by: Van B Mar 17 2022, 08:01 PM

@http://www.914world.com/bbs2/index.php?showuser=24231 my AAV shows continuity and passes the freezer and hair dryer test so, I don’t know how else to test it. But you can see my post above to know I’ve got no pride in my diagnostic skills. I’ll replace whatever I have to in order to get this thing running like it wa designed to.

Posted by: wonkipop Mar 17 2022, 08:03 PM

will be real interested in this.

i think i mentioned came across that old bus blog which had some kind of definitive time on the aav of 8 minutes to fully warmed engne. but it did not say from what temp it started. given it was a usa blog from almost last century i'm guessing maybe colder regions of the states.

my guts tells me it should operate for at least 4-5 minutes here in aus in winter.
given thats how long the engine seems to stumble around for on its cold start mumblings.

its been a while since i tested my aav during recommission.
but i do think it may have been closing faster than that.

amazing that changing a hose relieved some of the strangulation symptoms.
but actually not when you think about it a bit more.

Posted by: wonkipop Mar 17 2022, 08:08 PM

yes there really isn't any test further than that other than having a good sense of/solid information of - time to take to close. thats all down to the heater coil element inside.
which repeated dose of electricity and warming weaken. so it closes too fast as a result.
ie expands too fast.

the 8 mins is the only thing i have stumbled across.
but i figure so long as its open and so long as it ultimately closes, then it does good the longer it takes so no need to be exact. 8 minutes is a good warm up.
2 minutes is death by oxygen deprivation. which has got to be a good part of the problem.

Posted by: Van B Mar 17 2022, 08:16 PM

Tomorrow, I will cold start and go for a drive. Then change out the AAV and try it again on Saturday morning. Or since you’re 14hrs ahead, you could just tell me how it all worked out!?!

Posted by: wonkipop Mar 17 2022, 08:20 PM

sounds like i should seriously consider getting rid of the points and doing the petronix ignitor. this variant you mention replaces the points?

i pulled out the crystal ball. its on the blink. the ruskis are jambing it.

Posted by: Van B Mar 17 2022, 08:27 PM

Yeah, and though I haven’t driven yet, I’m so far impressed. It replaces your points with basically a Hall effect sensor. As such, I have expectations for improved high RPM performance. For sure throttle response is noticeably improved as well as dwell stability under a timing light. With the points the timing mark would just kind of wiggle and oscillate ever so slightly, now it’s rock steady.

Posted by: emerygt350 Mar 18 2022, 12:40 AM

Going solid state (123 in my case) was one of the best things I did with mine. I loved the idea of going back to points but in reality, modern stuff is soooo much better. My old dizzy can sit on the shelf as a conversation piece.

Posted by: Van B Mar 19 2022, 07:10 PM

Guys, I think I have the cold start sorted. Not just back to the OE performance level that @http://www.914world.com/bbs2/index.php?showuser=10753 and @http://www.914world.com/bbs2/index.php?showuser=24231 showed with their timed examples, but a proper high idle warm up!

Along this journey I discovered several key issues:

I had poor injector spray pattern that was causing wash down on real cold days. It would manifest itself as a dead cylinder until the engine got warm enough to make the fuel sizzle and then it could ignite the vapors. Solution here was 4 NOS tested and flow matched injectors with a verified spray pattern. (I bought 7 to get those 4)

I had Bosch spark plugs that did not seat. The taper below the hex was hitting the shoulder on the recess for the plug prior to the plug seating and allowed compression and fuel/mixture to escape through the threads. Solution here was NGK plugs.

I had a dead thermo-time switch that meant I wasn’t getting the full 8 seconds off the cold start valve on actual cold days. However, it should be noted that the CSV does function while cranking even with a bad TTS.

I had hoses to and from the AAV that were 3mm too small in diameter. I got baited into this mistake by replacing the hoses based on the size of the old hoses I pulled off. They were old and nasty same as everything else in the engine bay so, I just assumed they were original, and correct. They were not.

And finally, the AAV I bought as an experiment has given me the ideal high idle! It’s meant for and ‘87 BMW M5. Externally, it is the same as the OE part. Also the passage is the same size. But what is different is the shape of the valve. It allows more air at all stages less than full open compared to the stock part.

So, with all the above, and even on a warm 75F/25c day, I got a full 8min of a steady 1300RPM warm up! This is in contrast to my start yesterday, which after reading back through this thread, was pretty on par with what the guys described on their car.

More details on request

Van