[Es2] Sport Quattro problem

[Ben Klumper]

Colin,

When was the last time the O2 sensor was replaced?

Ben

----- Original Message ----- 
From: "c cohen" <ccohen5 at compuserve.com>
To: "es2" <es2 at audifans.com>
Sent: Monday, December 06, 2004 1:29 PM
Subject: [Es2] Sport Quattro problem


You guys have been kind enough to help shed some light on the mysteries of 
the KW engine in the light of your terrific AAN et al performers.  I wonder 
if you would take a look at this problem and tell me what you think.

Starting in the Spring, it would occasionally run rough - as if it was only 
running on 3 cylinders, but this was not the case.  More like cutting out 
momentarily - would not accelerate but could maintain speed with very light 
throttle.  You feel like going to WOT but you know it will probably die 
before you get there.  Then just as suddenly as the symptoms started, it 
cleared up and ran normally.  This happened in daylight (no lights) dry but 
around 28C with the A/C running.  I switched off the A/C but that did not 
help.  the shop I work with in TX thought it was the diverter valve and 
replaced it with one for a TT. the problem did not return but the car was 
not driven as regularly after June.

In September, after a 300 mile run, 4 track runs and 275 miles home, all 
flawless, the problem started again.  This time it got so bad that when I 
stopped for a light, it stalled and would not start. There was spark 
(checked) but a seemingly no fuel was getting through.  The A/C was on but I 
had switched it off well before it stalled.  I had just refilled and thought 
it might be bad gas.  I got a tow to the other side of the intersection and 
started calling for another tow.  After 15 minutes of phone calls, I turned 
the key, yet again, and its started, ran smoothly as if nothing had happened 
and home I went.  Warm dry day, 27-30 deg. C.

Later in the same month it happened again but this time it did not stall and 
cleared itself up after some nursing.  I then put in a bottle of the Chevron 
injector cleaner.

Two weeks ago, I drove a round trip in driving rain with and without A/C, 
20-25 deg C.  No problems.

On Friday I drove it to work (30 miles round trip) and  as I pulled into my 
garage that evening, it started running rough again.  Tried to keep it 
going, played with all the electrics - but nothing made a difference.  It 
was hunting, revving to 2000 then dropping to near stall, then back to 2000 
until it finally stalled.  Cold dry day around 14 deg C.  Once it stalled I 
could not restart but smelled unburned fuel.  The next morning the car 
started as normal - ran smooth.
I am guessing it might be something to do with the fuel pump but it is not 
noisy; or filters, which were changed last year.  There is no workshop 
manual for this car but I do have the calibration numbers for the various 
sensors but do not know where to start.

One suggestion has been the fuel return or the accumulators?

Anyway any ideas would be appreciated.

Colin
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