Well that's pretty cool! I bet it was the cold start performance that sealed the deal lol

We’ll, at least it got me there and back - an hour+ drive each way. Ran like a champ on the way down at 65-70 F. Struggled at idle and stoplights (cut out twice but restarted fine) on the way back at 85F and oil temp gauge at highest I’ve had it for decades - the needle a good tad past middle of the gauge.
Mine has never liked hot, humid weather.

You really need that nice and toasty engine for setting your fuel trims. I'd be curious to know what they were in the different conditions.

Absolutely, you could be running too lean, or too rich. Mine would do that too, on hot and humid days, didn’t do much for inspiring drives in traffic. Next time pull over, pop the top off the AFM, and ever so slightly push the wiper both ways. That’ll at least give you an indication of what it wants, if and you can make that idle adjustment with the mixture screw on top of the unit.

Righty richer

Lefty leaner…

@porschef
Did new AAR bench tests today. To get full closure when warm (12v input) I adjusted the disc setting to be fully closed, but at that setting then the “warm”(room) temp opening is then rather small.
Or I could set the cold (freezer) opening at maybe 85% of the factory setting for this unit but then the fully warm condition never fully closes the disc (as previously experienced with the borrowed unit.
Can’t seem to get both ends of the travel at the right spot.
Ok to use the latter combination so not so high an idle when starting but then never full closing when at operating temp?

you are going to need a trophy room, won't be enough space on the bookshelf.



74 1.8 destined to be a classic (to quote you a couple of years back.

aav alternative translation from the german = mental torment inducing torture device.

they got the design from the swiss, to quote orson welles in the third man, who have invented only one thing.
the cuckoo clock

I’m noticing a trend here… @StarBear likes to adjust things when they are just north of room temp lol. You need to get that AAV up to proper temp before you go make adjustments. That heating element won’t get to the 130-140 degrees that it gets to sitting on top of the engine case.


Also, both the AAV and the idle bypass screw are metered air. So, you need to go on a nice highway drive to get everything nice and toasty, then come back and set timing, and then idle.

I don’t know how low you oven can go, but if you really want to know what the AAV looks like when heated, you’ll need to bake it at 140 and then try not to burn yourself looking down the barrel

With the AFR gauge, around 13.6 at idle and 10.6-12.5 or so when driving. Of course, all over the place depending on gear, incline, acceleration, and coasting. No data logging. Have turned AFM adjustment screw out (left) another 1/2 turn but will wait until new AAR is in before tweaking further.

Slightly rich, but definitely in the window!

Hehehe. You’re right, of course. Will do the oven test; wife is out of town so I can now do that sort of thing!

more like 13.6 cruising and 12.5 on acceleration. Running a little rich

Did oven test to 140-150F. Still didn’t close all the way. Will do another tomorrow.
Thanks, Geezer. Will shoot for that range once the AAR is settled.

Well, that amount it was still open is definitely what you need to adjust. I would have high confidence in that.

Between Saturday night and the present moment we’ve had some rocking Tstorms. Power just got knocked out along with internet. So what to so at 3am when you can’t sleep…

Didn’t get a chance yesterday to check the cold start, I may in a few hours. Anyway, a couple things I found; thankfully the unit can be dialed down because initial installation led to a very high cold start isle, about 1900 rpm. Too much. So there was some trial and error and waiting involved in getting the idle right around 1200 at start. Somewhat frustrating that the factory unit was just so close, but not quite open enough for a decent start.

I’d say I adjusted the orifice to just about halfway closed, give or take. Next start will tell if I need to make another adjustment.

Shooting for that 12-1300 rpm.

The other thing is that the BMW unit has slightly longer “tubes” that have a flare, the factory unit does not have them, making things a little tight. So, I actually cut the flares off, matching the dimensions of the original. Good idea? Who knows, I’m stuck with it regardless as it’s real close to doing what it’s supposed to do…

I also checked the TTS function, it was right in the ballpark, so I put it back. Easily removed by backing out the cheesehead screw that fastens the mount. The way that harness takes that near 180° bend is wacky, plus it’s right up close to the distributor.
Would be nice to see if a 912e unit works better (Van) but I don’t drive it much in the winter, so it’s probably not something I’ll seek out.

Steve, thinking back (always a challenge) I remember my hot idle was too rich. Pre AFR days. So you may have to back out the screw some.

Ahhh, the relentless search for perfection. Is there such a thing??

[quote name='Porschef' date='Aug 15 2023, 01:31 AM' post='3095711



Ahhh, the relentless search for perfection. Is there such a thing??
[/quote]

we are mere humans @Porschef .

perfection is best left to the ancient gods.
you never want nemesis to walk in the room shortly after hubris has left.
best to settle for just good enough.
as the japanese always wisely do.

Believe me, close enough is usually my MO. Certain life situations have a real way of humbling one…
It’s just…just…I want a good cold start dammit!!!

Dig through my files and found a short write up from www.hi performance store.com/ljetronic.hum
“…. If you fiddle with it enough you can get it to open most of the way and close most of the way which is how most of them were set at the factory.”
So maybe that’ll be good enough - a bit more open at cold for starting and expect a small left over opening at warm.

A final (?) question: ok, if I accept a bit remaining opening at warm condition, this continues to allow a bit of excess unmetered air into the plenum, thus leaning out the AFR?

Yeah I did a fair amount of fiddlin’ with it, I’ll check it shortly if’n the rain quits. Power’s still out…

The fiddling in my brain now wonders if had I gotten creative with a dremel could I have opened up that screw slot just enough to crack it open a wee bit more.

We may never know… But it’s a moot point now

You're killing me Steve. All air is metered on the way in.

Both of you bought this part and are now slowly trying to adjust them down to how the car used to run. This is borderline Stockholm syndrome

Actually Steve, I think it is metered. Had to reboot the brain on that one. It’s still pulling air through the AFM into the plenum, hence increasing fuel also. The cold CHT sensor tells the brain in the car (probably superior to mine) to add fuel. I think.


I believe the only unmetered air would be that which goes through the bypass via the idle mixture screw on the top of the AFM unit itself.

The one I think you may have to back out a bit…

It’s all your fault Van! Regaling us all with tales of a near perfect cold starts…

Then you should enjoy it!

Hah, it’s all good.

Ok, couldn’t take the suspense any longer, so I went out and gave it it’s official first cold start. 1100 rpm steady idle. I’m gonna call it good.

And wouldn’t you know it, looks like the clock quit working.

It’s always something

you will be spared a random lightning strike on the golf course with that wise show of humility. close enough is good enough for a cuckoo clock.

clocks - a swiss thing.

you would think he would know that having just stuck a new AFM in.
i mean where the hell else can it get there from.

apart from leaky old hoses.

just

1,8s =

Ah, right you are. I checked the hoses and the unit pulls in air downstream of the AFM so it is metered. Now it makes senses. Per Van, I’m way overthinking this.
The AFM screw is already almost all the way out. Will put in new AAR and adjust things from there.

nothing wrong with over-thinking.

you need to come out of retirement and do some work for NASA.
i don't think they are trying to mate cuckoo clocks with primitive prototype electronic "brains". you are wasted trying to resolve the inherent incompatibility of components the jerries fudged in 1974. they got close (and then said, close enough).
ze teknowledee iz nut defelhopped enuff, but no vun vill ever NO until ze 21st zentury in neu jerzey and ve vill be dead und kaput. ya).

Hah!
It IS the 21st century and we still don’t know (though getting closer)!
Wife is out of town so focusing on completing the renovation of the back room bathroom that I didn’t quite finish 10 years ago.
Not sure which is harder to do - get the AFM/AAR squared away or doing the part of the bathroom I knew would be hard so didn’t do it then.

Bathroom... They are generally a shitty place to be.

I'll see myself out now

@Van B and @StarBear .
i estimate i have designed roughly 250-300 bathrooms in my miserable career.

just ask and you shall now.


i hate tiles. cleaning? for those i can convince i chose either agua-panel (sheer sheet laminex) = budget or slabs of pure marble = money people.

i do nothing in between. thats for compromise. which i don't do. call me communist or call me red neck, but one thing i refuse to be is MOR.

grout joints. bugger that. thats like making every shower like reparing the space shuttle after it has re-entered the atmopshere.

my bathroom is easy clean. wipe her down like paint duco.

or as they say in outback aussie lingo when referring to coved concrete creations called country pubs, she is a hose down job.

Done! Trial testing completed!
The 914 repair experience of strong core and ability to attach things blindly, usually with just fingertips, came in handy.
Relax and cleanup this afternoon then back to swapping out AAR tomorrow.
Back to the thread….
Click to view attachment
Click to view attachment
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I've cleaned up old clogged AARs before. As long as the heating element still works, there's a process to clean the coke out of the ports.

I did a write-up years ago - not sure if it was here on WORLD or the old NARP forum

Putting PB Blaster or diesel fuel in the ports and capping them, then applying 12v power to heat the unit up, then uncap and drain and shoot compressed air through the unit.

Several sessions were required, but it eventually cleaned the internal mechanism enough to be fully operational again.

That’s better that most pros steveo!

Does indeed look good. Glad to see others of our “advanced” age getting it done. A real sense of accomplishment. Not to mention it clears the plate for more important stuff….

Yesterday was the first key through the window cold start in the 13 years that I’ve had the car. Only thing with Ljet is it’s gotta crank a few times to build fuel pressure. But once that happened, it fired up with a nice 1200ish idle.

Took a 50+ mile ride with it, after about 5 miles it settled down to a normal idle.

I’m good with that

Awesome news development. Hope to get mine in tomorrow, followed by a nice drive - maybe to a nearby National Park.

And a whole lot cheaper!

Porschef, is that with the AC358 AAR valve? What adjustments did you make if any?

Yes. Running it straight out of the box made for too high of an idle.

I believe the factory unit came this close to working, but just didn’t have the volume. On a stock 1.8, maybe. I closed the 358 unit down almost halfway if I was to estimate it.

There’s certainly room for adjustment. Trial and error, with some waiting in between...

Ok, new larger AC358 (BMW) Bosch 125 AAR installed. Runs just like the borrowed unit; definitely takes a bit longer to settle down to a nice 1000 rpm idle than the stock unit do to larger opening.
The new one came with its room temp 74F opening a bit larger than the borrowed unit so adjusted it abut 10% more closed to be the same as the borrowed unit. See pic:

Click to view attachment

Now of course another issue has cropped up now that I can drive it for longer runs where the engine now gets to full temp. At full temp, Runs fine at cruise and acceleration but Cuts out at stop lights or other low rpm; restarts just fine. But that’s another thread after I investigate a bit…
A teener owner’s work is never done…

How old is your VR?

You mean the vacuum can? Maybe 15 years old. Replaced it once.

yeah whats the VR?

you talking about the double relay?
or are you saying @StarBear is inhabiting an old virtual reality?

Oh, voltage regulator? A few years old. Nothing odd on voltmeter but of course goes to 0 when shuts off. I have a spare new one.

Voltage regulator. I’m sure you all call it Bruce, Nigel, or something weird in Oz lol

It’s just a hunch. But I usually entertain them when they come around.

If you think that might be the problem, easy to swap and test. If so, definitely the easiest solution to do in many moons.

ah yes. right.

they are all called a prawn down here and the alternator is known as a barby.