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flosho

Well, out of no where essentially my car has developed a new problem. As of late my car has had a terrible time staying running. I will go to start it and if its cold, it will crank over and I have to use the gas to keep it running, by blipping the gas it will stay running, barely. If I let off the gas, the idle will drop under 500 rpm and die. Then it wont restart after it dies!

I've also tried to keep the RPMS steady at 2000 RPM or 2500 RPM, etc and it will hold steady at whatever RPM for a little while, then bog and almost die?

I've gone through and checked a lot of vacuum lines and can't find any that are cracked or leaking?

Any suggestions on where else to start?
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flosho · Posted: Wed May 23, 2007 10:36 am Post subject:

Quick update.. I was able to keep it running long enough to back out of the driveway and take it around the block. When I got back, it actually idled, and would idle at ~500 RPM and sound really rough. The vacuum/boost gauge said it was around 10 in mg... I shut it off, and tried to restart and it doesn't restart, just cranks and sputters.

This is why I thought it was a vacuum leak, and still may be, but it wont restart, and I've looked around in the engine bay to find a possible vacuum leak and cant come up with anything.
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Tigger937 · Posted: Wed May 23, 2007 10:55 am Post subject:

Did you wash it recently, especially at one of those power washer places? A wet/loose connector at the ignition module gave me the symptoms you describe more than once.
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1981 931 (Concours)
1982 931 (Daily Driver)

"Think outside the box"

flosho · Posted: Wed May 23, 2007 12:49 pm Post subject:

hmm.. I washed it about a week and a half ago.. It was the hand power washer kind. I will check what you suggested.
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Smoothie · Posted: Thu May 24, 2007 1:41 am Post subject:

In case that doesn't pan out, I had similar symptoms about a half year ago. The initial start was strong, but then the warm-up phase was crappei - I'd have to keep after it with the throttle to keep it running, then if I let it stall, it would refuse to restart. I wish I could remember more clearly, but I'm pretty sure what I finally found was that I needed to hold the pedal down steady to the floor and with that it would eventually restart - that suggested it was too rich for whatever reason. The problem appeared spontaineously and again I wish I could remember more clearly, but I think it went away on its' own too - though I may have messed with the AAV or something un-neccesarily in the mean time.

-Long story short, next time it won't start, try holding the pedal flat to the floor while cranking.
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"..it's made in Germany. You know the Germans always make good stuff."

'82 924T, US version, dark green metallic, 5 speed Audi 016G gearbox

flosho · Posted: Fri May 25, 2007 1:25 pm Post subject:

Yeah, I've tried the pedal at WOT when cranking it(once it stalls and wont restart) and it still does the same thing...
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Tigger937 · Posted: Fri May 25, 2007 11:58 pm Post subject:

Well, if you've verified there are no vacuum leaks and the ignition module is working properly, you might want to consider taking a peak at the injector spray patterns. A partially clogged injector could give you these symptoms.
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1981 931 (Concours)
1982 931 (Daily Driver)

"Think outside the box"

Smoothie · Posted: Sat May 26, 2007 12:34 am Post subject:

Doh! (My memory of my problem a few months ago just returned this morning.)
It would restart if it stalled shortly after the initial start, but wouldn't restart if it had been running for a few minutes. -So my problem then was a too-lean condition... As the thermo time switch had enough time to deactivate the cold start valve, I wasn't getting any help from it on the restart attempts, so the temp fix was to pump the pedal while cranking to provide a richer mix.

Something like this of course could be due to clogged injector/s as Tigger mentioned, so a dose of Techron and/or injector spray pattern checking would be useful.
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"..it's made in Germany. You know the Germans always make good stuff."

'82 924T, US version, dark green metallic, 5 speed Audi 016G gearbox

flosho · Posted: Thu May 31, 2007 12:10 pm Post subject:

Ok, just ran some sea foam injector cleaner through the car for a few minutes and its still doing the same thing.

If it dies right away it'll restart pretty much immediately. If I keep it running by giving it gas and keeping the revs up, and after a few minutes if I let it die, it will not restart. I've tried pumping the gas and holding the pedal down and neither method gets it to restart. It will only restart after a few minutes of sitting.

After I start it up, if I dont keep giving it gas, or revving it 2-3000 RPM it will always die on me.. Sometimes it tries to idle at like <400 RPM.
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Smoothie · Posted: Thu May 31, 2007 12:50 pm Post subject:

Well, my guess at this point is that you're way lean for some reason. The symptoms are similar to what I had, suggesting that it needs the extra shot of fuel from the cold start valve to restart and isn't getting that after the engine is kept running for a few minutes. Then given a few more minutes to cool down after it stalls, the thermo-time switch is reset and you get the cold start valve activation and a good restart.
The difference from my situation is that you're waaay lean while mine was less lean, so the pedal pump trick isn't enough to bring your a:f mix up enough to restart. Have ye been messin' with the a:f mix lately? -and/or the lambda system? -idle speed setting?-this affects timing at idle on '81-up 931s. Couldn't be as simple as a vacuum leak, could it? -or WUR stuck closed?
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"..it's made in Germany. You know the Germans always make good stuff."

'82 924T, US version, dark green metallic, 5 speed Audi 016G gearbox

RC · Joined: 25 Mar 2007 Posts: 2637 Location: Australia

Flosho, you wrote:

Vince Ponz · Joined: 02 Nov 2002 Posts: 3581 Location: Florida

Good guesses.
Ignition switch for one
fuel filter second so, detach battery, remove sending unit, remove fuel pump when you are low on gas or catch the exiting gas in a large container. Strain about 2 gallons to remove rust. Yes rust and you may find plenty. Do this about 5 times install new fuel filter replace battery, sending unit and you should be good.
Look for kinked lines and lastly if it is a turbo in the turbo is a rubber nipple that could be holed. My was and the car ran great. I changed the nipple.
Bad gas could be it too.
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"Never let them see you sweat"
77.5 924 modified track car
79 931 Euro stock
88 924S SE
87 911 Targa stock

flosho · Posted: Fri Jun 01, 2007 12:10 am Post subject:

Tigger937 · Posted: Fri Jun 01, 2007 2:47 am Post subject:

9xx · Joined: 18 Jun 2006 Posts: 627 Location: Jarvenpaa, Finland

Flosho, did you ever find out what the problem was?
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Mikko

All gone: 931 '82 Alpine White, original option "220" G31 with LSD + 3 x 944