[s-cars] Need Diagnostic Help

[Robert Pastore]

Bob:

It's the boost line to the ECU, or a bad MAP sender in the ECU.  When on
vacuum, the car can still run normally, but once the maf versus the MAP
becomes implausible, the ECU kills the party.

rgds,
Bob 

-----Original Message-----
From: chad clark [mailto:chadaclark4 at msn.com]
Sent: Friday, December 12, 2003 5:53 PM
To: Bob Rossato; S-Car-List
Subject: Re: [s-cars] Need Diagnostic Help


Bob, I must add that while you are sure it's not a failing coil pack, I
would like to relate my experience. I had an opportunity many years ago to
help a friend diagnose a sudden and abrupt power loss during WOT in a
chipped '93 car. As soon as boost came on, massive stalling/bucking. But, as
soon as you backed off the accelerator and ran through the rpms with out any
boost, no bucking was felt. Eventually he swapped a new coil pack cylinder
by cylinder, went for a test drive and sure enough, coil 4 was toast.

Try the simple things first as others have mentioned = clean contacts and
such. It could be many things. Just wanted to add another experience with a
failing ignition coil. HTH,

Chad 


on 12/12/03 1:30 PM, Bob Rossato at 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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