[s-cars] Need Diagnostic Help

[Robert Myers]

Sounds like you may have hit the overboost limit.  It acts the same as the 
rev limiter - it just shuts the engine off briefly and produces a nice 
brick wall effect.  :-(

A possible cause might be a torn/split wastegate diaphragm.  Or possibly 
the manifold pressure connector to the lower wastegate chamber may be 
off/loose/leaking.


At 03:30 PM 12/12/2003 -0500, Bob Rossato wrote:

>Hello fellow S-heads,
>
>A friend of mine is having some intermittent cutoff problems on his S4.
>It happens during wide open throttle.  He states that it is not like a
>misfire, it's more like a hard cutoff such as hitting the rev limiter,
>though he's nowhere near the rev limit.  Has happened a handful of times
>over the last few weeks.  When it's not acting up it pulls strongly, so
>I wouldn't suspect the usual ECU boost line coming off as it wouldn't
>reseal it self.  And besides, he's adamant that it's not just a loss of
>boost, it's a complete loss of power.  Again, only during WOT.  Ease off
>on the throttle and the engine comes back.  I also wouldn't suspect the
>POS or coils as I would expect that to be more of a misfire, not a
>complete loss of power.
>
>We checked the codes today and got the following 3 codes:
>
>00519 - Intake Manifold Pressure Sensor (G71)
>             06-10 - Signal to High - Intermittent
>00561 - Mixture Adaptation
>             14-00 - Adaptation Limit (Add) Exceeded
>00544 - Maximum Boost Pressure Exceeded
>             27-10 - Implausible Signal - Intermittent
>
>The 00561 mixture adaptation I've seen before on my car and others but
>I've never noticed anything wrong performance wise so I don't think
>that's the first thing I'd chase down.  The 00519 & 00544 are more
>relevant I think.  Is this an indication of a problem with the WGFV?  We
>will be checking the line to the ECU and water trap, as well as boost
>hoses anyway just to make sure.  Any other thoughts?
>
>The car is a '94 S4 with ~53k miles.  Completely stock.  And let's see,
>what else... oh yeah, it's Pearl White if that helps.
>
>Bob
>
>
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_____
"I never give them hell. I just tell the truth and they think it is 
hell!"  Harry Truman

Bob
*****
  Robert L. Myers 304-574-2372
  Rt. 4, Box 57, Fayetteville, WV 25840 USA WV tag Q SHIP
  '95 urS6 Cashmere Grey - der Wunderwagen  ICQ 22170244
  http://www.cob-net.org/church/pvcob.htm
*****