[s-cars] Need Diagnostic Help

[chris chambers]

Bob,

I had this exact same problem...I called it the bucking S4.
What was happening with mine is that the ecu thought I was hitting
overboost and cut off the fuel pump.

After doing alot of searching (and replacing plugs, oxy sensor, etc.) I
discovered this write up on SJM's site:

http://www.sjmautotechnik.com/20vboost.html

Basicly if you have the same problem I had either there is a bad maf or
if you are like me dirty contacts on the MAF. I cleaned my contacts
with electrical contact cleaner and haven't had a problem in over 5
months now.

HTH

Chris




--- Bob Rossato <bob.rossato at att.net> 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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