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Van B
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? confused24.gif

-Van

See post #419 on page 14 for a synopsis of the outcome.
emerygt350
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.
Van B
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 unsure.gif
emerygt350
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.
wonkipop
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.

beerchug.gif
Van B
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
emerygt350
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.
emerygt350
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.
wonkipop
QUOTE(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


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.
wonkipop
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.
Van B
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?
wonkipop
QUOTE(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?


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.


Click to view attachment


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.
emerygt350
QUOTE(wonkipop @ Nov 8 2021, 05:16 PM) *

QUOTE(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?


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.


Click to view attachment


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.


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.
Van B
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! oilleak914.jpg
Van B
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.
wonkipop
QUOTE(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.



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.
Van B
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.
wonkipop
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.

Click to view attachment Click to view attachment


as far as i know there is not much you can do about temp sensor ! in the AFM unit.
its part of the unit.
Van B
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!
wonkipop
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 beerchug.gif
i assume he lives in the USA somewhere. smilie_pokal.gif


i'm looking forward to your discoveries re the warm up phase.
you will get to them before me.
Van B
Oh man this is gold! Thank you good Sir!
wonkipop
QUOTE(Van B @ Nov 8 2021, 08:52 PM) *

Oh man this is gold! Thank you good Sir!



smile.gif


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.



wonkipop
QUOTE(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!



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 @Van 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.
Van B
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 driving.gif
wonkipop
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 - driving.gif w00t.gif

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.
StratPlayer
I just had a microsquirt sys. installed on my 2.0. Still working out some bugs but very happy with this system.
wonkipop
@Van 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.
Van B
I’m an Air Force transplant here since 2019. My actual citizenship belongs to the Republic of Texas. shades.gif
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!
wonkipop
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.
Van B
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.
Van B
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?
StarBear
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. driving.gif
Van B
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.
Van B
QUOTE(StarBear @ Nov 11 2021, 04:02 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. driving.gif

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 dry.gif
emerygt350
QUOTE(Van B @ Nov 11 2021, 04:54 PM) *

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.


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?
wonkipop
QUOTE(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.


i was expecting it find out it was a mcdonalds. smile.gif

interesting about the spark plugs.
wonkipop
QUOTE(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.


i was expecting it find out it was a mcdonalds. smile.gif

interesting about the spark plugs.
wonkipop
QUOTE(emerygt350 @ Nov 11 2021, 04:01 PM) *

QUOTE(Van B @ Nov 11 2021, 04:54 PM) *

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.


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?


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.
wonkipop
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.
emerygt350
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).
wonkipop
yes @emerygt350 , 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.
StarBear
QUOTE(wonkipop @ Nov 11 2021, 06:34 PM) *

yes @emerygt350 , 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.

That info ( part numbers and such) would be a grand resource! New or even good used AARs not seen in 20 years!
StarBear
QUOTE(wonkipop @ Nov 11 2021, 06:34 PM) *

yes @emerygt350 , 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.

My mechanic found a Volvo hose bend that fit perfectly. Pre-bent so doesn’t pinch.
That alt test is much easier, for sure.
wonkipop
QUOTE(StarBear @ Nov 11 2021, 06:13 PM) *

QUOTE(wonkipop @ Nov 11 2021, 06:34 PM) *

yes @emerygt350 , 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.

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


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.
Van B
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.
emerygt350
QUOTE(Van B @ Nov 11 2021, 08:22 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.


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.
Van B
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?sho...p;#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
wonkipop
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.

Click to view attachment


--------

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).

Click to view attachment


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.

Click to view attachment


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.
Van B
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!
Van B
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
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