RE: 20V acceleration loss

[Larry Smeins <lsmeins@ball.com>]

Ralph,
Your problem sounds very familiar to one I experienced with my 87 5KCST.
I found that the problem was caused by a plugged inlet screen on the
fuel pump.  I found the fault by monitoring fuel pump pressure under
conditions that produced the problem.  The pump screen had a film of
what appeared to be silicone sealant covering it.  I expect the film
came from a batch of contaminated fuel.  The problem started as a sumble
and miss at full throttle on hot days.  It progressively got worse and
one day I found myself stranded between two hills on a hot day.  After
the sun went down things cooled enough that I made it home for more
troubleshooting.  I won't go into the detailed explanation of what was
happening but it all makes sense.  The main fuel filter could produce
similar problems if plugged and that is the first thing I'd try but
getting at the pump and cleaning the screen isn't too hard if Audi
didn't change the tank design between our models.  I made my own tool
for removing the pump retainer and did the job in less than an hour.

Try my suggestion since it won't cost much and could solve your problem.
It took me two months to track the solution down on my Audi.

Larry
If you don't care where you are, you ain't lost.
87 5KCST
84 4KS
95 F-250 Powerstroke 4x4
91 Suzuki Sidekick 4x4
84 S10 4x4
67 Porsche 912
71 VW convertible

> ----------
> From: 	Ralph Poplawsky[SMTP:ralphp@cellport.com]
> Sent: 	Thursday, July 31, 1997 9:27 AM
> To: 	quattro@coimbra.ans.net
> 
> Can anyone help me?  My '91 200TQ 20V has acceleration loss and the
> dealer
> may own my house before it is fixed.  The symptom is as follows.  The
> car
> runs like a top up to about 1/2 to 2/3 throttle.  After that there is
> intermittent power loss varying from a 'missing' feeling to cutting in
> and
> out to stumbling along and hardly accelerating.  If I back off on the
> throttle when this happens, the engine smooths out and acceleration
> actually
> increases.  The problem appears to be worse in hot weather.  The boost
> gauge
> reads full boost.  Repeated acceleration runs sometimes result in
> temporary
> improvement.
> 
> Some background:  Several years ago, there was a similar problem, but
> with
> boost loss.  The dealer spent $5000 (in warranty) swapping parts to no
> avail, and finally figured out (from the factory) that the cam timing
> was
> slightly off, the computer was sensing too much advance and shutting
> down
> boost.  The current problem began after the 60K mile service at which
> time
> the dealer replaced the timing belt.  I don't know if the current
> problem is
> related to cam timing or the 60K service, but I'm suspicious.  
> So far, my dealer has charged me $250 for a new O2 sensor which has
> not
> fixed the problem.  He wants the car back to 'go further' but can't
> really
> say what that means. The owner of the dealer suggested that the
> regional
> service rep would be in, so why not have him look at it.  So, I gave
> him the
> information and later heard from the dealers' service department that
> he had
> nothing to say about it because he is only interested in 'in-warranty'
> vehicles. 
> 
> If anybody has had this problem, or has any good advice. I would be
> very
> grateful.   
>