1983 Audi Coupe GT - Engine stalls on quick acceleration

Tue May 18 07:42:57 PDT 2010

Just to chime in... i had the exact same conditions on my CGT (The one
Andrew describes the fix to...) ... it would run 30 minutes and then DIE on
me it was so bad lol....and then Andrew comes over and manages to fix it and
drive away... Anyway.. I'd check Andrew's solution out.. really seems to be
same symptoms here.

On Tue, May 18, 2010 at 9:21 AM, Andrew Dickinson <amdickinson at rogers.com>wrote:

> Sounds to me like an A:F issue.  I gave the text here a quick read and
> didn't see mention of the O2 sensor.  If it has or hasn't been changed there
> could still be issues.
>
> Put a multimeter on the O2 sensor wire and see what it reads.  A cheapie
> anaolg works best for this.  0 to 2VDC range.  Once warm the signal should
> fluctuate.  If it shows a constant value then the sensor may be shot.  If it
> does appear to fluctuate then check the CIS system Zero and Basic settings
> (sensor plate height) and fine tune from there.
>
> If the O2 signal is pegged high then the CO adjustemnt may be way out of
> spec.  This happened with the coupe I picked up from Hayes.  The CO was
> adjusted to chase a failing O2 sensor.  Once I adjusted the CO to a
> reasonable value she ran perfectly.  It all depends on how or if the O2
> sensor is failing/failed.
>
> HTH.
>
> --- On Tue, 5/18/10, dgraber460 at aol.com <dgraber460 at aol.com> wrote:
>
>
> From: dgraber460 at aol.com <dgraber460 at aol.com>
> Subject: Re: 1983 Audi Coupe GT - Engine stalls on quick acceleration
> To: AUDICPGT at aol.com
> Cc: quattro at audifans.com
> Date: Tuesday, May 18, 2010, 9:05 AM
>
>
>
> Christopher;
> Don't give up yet. I have often been where you are and this list
> (especially Huw) talked me off the ledge.
> I have the JC Whitney gauges you are welcome to borrow if you like. Just
> promise to send them back.
> You have done a good job of narrowing down the suspects. You are close to
> outing the accursed culprit.
> Do the plugs look lean or rich after the problem?
> Let me know if you want me to send the gauges. (and where to send them)
> I might have some parts that would help as well. I will check my stash
> tonight.
>
> Dennis
> Denver
>
>
> -----Original Message-----
> From: Huw Powell <audi at humanspeakers.com>
> To: AUDICPGT at aol.com
> Cc: quattro at audifans.com
> Sent: Mon, May 17, 2010 5:37 pm
> Subject: Re: 1983 Audi Coupe GT - Engine stalls on quick acceleration
>
>
> It's CIS-E, right (aluminum fuel dist. body)?
> It's an unlikely thing to cause this, but check the WOT switch for
> unctionality.
> Another unlikely thing to consider is to check the throttle bits to see
> f any are doing something weird, like, say, shorting out a worn wire,
> r opening a vacuum leak.
> Btw, that engine/system shouldn't stall when the oil cap is removed.
> Also, since the engine "rotates" a bit on its mounts when you floor it,
> t could be opening up an intermittent vacuum leak, under the big intake
> ose thing, for instance.  What kind of shape are your engine mounts in?
> AUDICPGT at aol.com wrote:
> 1983 Audi Coupe GT 2.2L I-5  Miles = approx. 220K
>
> What started out as a random issue has now become a constant problem... as
> follows:
>
> Engine starts fine cold, idles fine also.  Upon quick acceleration,  engine
> cuts-out, as if complete loss of fuel pressure, ignition spark or  engine
> vacuum dropping the fuel metering plate.  If I stay in the pedal,  the
> engine
> will die... if I jump off the pedal and feather it, it will stay  running.
> On very easy acceleration, it will rev up normally to the  redline.
>
> I checked all my vacuum lines for leaks - cracks - looseness, sprayed some
> starting fluid around connections... all seem fine, no spikes in idle.
> Removing oil filler cap does make engine die.
>
> I suspected plugged up fuel filters since I have been there before on
> another vehicle of mine.  I knew it had been at least 5 years,  so I
> replaced
> both filters, and also my fuel pump that has been louder  as of late since
> everything was disconnected anyway. I don't have a CIS fuel  pressure test
> it,
> so I had no problem shot-gunning these replacements.   Also, while I had
> the filters disconnected, I checked the free-flow out of the  fuel tank...
> it
> was strong, no obstructions there.
>
> Testing upon reassembly = No change!
>
> I was advised to replace my fuel distributor (it had been seeping), so I
> did w/ a rebuilt unit from Python.
>
> NO CHANGE!
>
> I suspected stuck open fuel injectors causing fuel pressure drop in
> distributor... so, since I had never had them cleaned I decided to take
> them
> n
> to Doctor Injector.  The guy said that they were gunked up, but sprayed
> fine
> now.  I was optimistic.
>
> Reinstalled injectors (new seals too) = NO CHANGE!
>
> I wanted to check and see what happens with spark during the event.  I
> hooked up my timing light, find steady strobe on idle... rev'd up the
> engine
> slowly, strobe sped up normally.  From idle, quickly opened the throttle,
> the strobe sped up, and when engine cut-out the strobe continued to
> pulse...
> SO, I surmised that the ignition system is NOT the  issue.  Spark is being
> generated at time of stall.
>
>
> I next considered waving the white flag and taking it to a shop  that had
> the proper fuel system diag equipment I didn't have... BUT  FIRST...
>
>
> Years ago, I had another car that the Cat convertor disintegrated &
> plugged up, creating huge back pressure to the engine.  That car acted
> imilar to
> my GT's problem, and I wondered if this was the case, it could be  causing
> back pressure that would affect the fuel metering plate.  I  disconnected
> the exhaust to inspect the Cat... it looked fine, I could easily  see right
> through it.  Discouraged, I decided to run open-header to  eliminate any
> questions about the entire exhaust system...
>
> NO CHANGE!  Engine roared to life, idled fine, BUT cut-out on the snap
> accelerations!
>
> At this point I've reached that PUT-A-FORK-IN-ME-I'M-DONE stage.  I  feel
> beaten (which rarely happens to me with my vehicles).
>
> I found this forum, and decided to give it a shot before limping it to the
> shop.  The old GT has been a reliable commuter (keeping miles off my
> Infiniti G35 Coupe), so I can only hope it is something simple I have
> overlooked, and not expensive as to be cost prohibitive in fixing.
>
> I thank you for withstanding my saga, and also for any ideas you may have
> for me.
>
> Christopher
>
>
>
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> --
> uw Powell
> http://www.humanspeakers.com/audi
> http://www.humanthoughts.org/
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