[s-cars] Need Diagnostic Help

[The Gagnons]

Bob

 I had this problem for about a year, intermittent over boost safety cutout
during full throttle.  It turned out to be something to do with the MAF.

I had a shop replace something (I can't remember what it was) which required
them to remove the MAF to access.  When they reinstalled it my problem went
away (it has been over a year now).  I had fiddled with the MAF before with
no luck.

I did notice that there was a difference about the way they installed the
MAF to the hose that feeds the turbo, I had always fastened the
hose clamp to the hose AND around the support to hold the MAF in place (this
is the way I found it, so that is the way I put it back).  The shop had
installed the clamp ONLY around the hose and let the MAF just rest on the
support.  I concluded that the original installation allowed some air to be
sucked into the engine without being metered which caused the ECU to figure
that something was wrong.

Hope this helps, It took me a long time to figure that one out! Even then it
was by accident!

Jack

> -----Original Message-----
> From: s-car-list-bounces at audifans.com
> [mailto:s-car-list-bounces at audifans.com]On Behalf Of Bob Rossato
> Sent: Friday, December 12, 2003 3:30 PM
> To: S-Car-List
> Subject: [s-cars] Need Diagnostic Help
>
>
> 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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