1983 Audi Coupe GT - Engine stalls on quick acceleration

[brian hoeft]

you say the WOT switch is unlikely but i think its a good lead, or the
closed throttle switch if it has one.. ??


On Mon, May 17, 2010 at 7:37 PM, Huw Powell <audi at humanspeakers.com> wrote:

> It's CIS-E, right (aluminum fuel dist. body)?
>
> It's an unlikely thing to cause this, but check the WOT switch for
> functionality.
>
> Another unlikely thing to consider is to check the throttle bits to see
> if any are doing something weird, like, say, shorting out a worn wire,
> or 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,
> it could be opening up an intermittent vacuum leak, under the big intake
> hose 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 kit,
> > 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 in
> > 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
>  similar 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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> >
>
> --
> Huw Powell
>
> http://www.humanspeakers.com/audi
>
> http://www.humanthoughts.org/
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>



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