[Biturbos4] Check engine light

[j.koenig]

Aurangzeb, David, et al:

The actual faults that can store one or more of the various "misfire" DTCs (Diagnostic 
Trouble Codes) are numerous and varied.  It's probably worthwhile to get someone on the 
case who really knows what they are doing; this may be a case where it's an advantage to 
go to a good dealer technician (and their proprietary diagnostic tool) than to trust a 
more general, less specifically informed diagnosis and throw parts at the problem.

It's also worth asking the dealer about a Technical Bulletin that described re-flashing 
the ECM software to address some early ('00, '01) driveability problems.  My understanding 
is that it dealt with changing some of the parameters that were too sensitive and too 
quick to store a code and switch on the MIL.  Sorry, I don't recall the TB number; I'll 
post it if I can find it.

The fact that the system resets and the MIL goes off after a few cycles is encouraging, 
but it's probably not going to stay that way.  As for fuel injection cleaner (I favor 
Techron), it can't hurt, and who knows...

Good luck, guys!


----- Original Message ----- 
From: "David Bray" <brayd at rogers.com>
To: "'BiturboS4'" <biturbos4 at audifans.com>
Sent: Thursday, December 06, 2007 2:54 PM
Subject: Re: [Biturbos4] Check engine light


Gentlemen,

I have the same car ('01 S4, 6 spd, Oct '00 build date) with less than 60k
miles (about 95,000 km) and a similar problem.  I never accelerate hard when
the car is cold, but 3 times (twice last winter and once this winter), when
I accelerated hard with the engine and oil up to normal operating
temperature, but the ambient temperature below freezing (say, -10 degC), CEL
would occur (resets after 3 starts).  Other than this, I haven't noticed any
loss of power or smoothness, hard starting, etc.

When I had it checked (I don't have VAG com), I was told it was an 'engine
misfire'.

Would it be useful to run some injector cleaner through it?  One mechanic
suggested changing fuel filter and/or plugs.

Thanks for any further thoughts.

Cheers,
David



> -----Original Message-----
> From: biturbos4-bounces at www.audifans.com
> [mailto:biturbos4-bounces at www.audifans.com] On Behalf Of Rhett Ennis
> Sent: December 6, 2007 11:48 AM
> To: Mark R; ama-list at mltp.com
> Cc: biturbos4 at www.audifans.com
> Subject: Re: [Biturbos4] Check engine light
>
>
> Agreed.  And it's definitely time to get that timing belt replaced.
>
> ________________________________
>
> From: biturbos4-bounces at www.audifans.com on behalf of Mark R
> Sent: Thu 12/6/2007 8:44 AM
> To: ama-list at mltp.com
> Cc: biturbos4 at www.audifans.com
> Subject: Re: [Biturbos4] Check engine light
>
>
>
> No, that's no indication of an impending timing belt problem,
> but you're at
> the mileage for one as preventative maintenance.
>
> Accelerating quickly when cold is not advised until the
> engine is fully
> warmed up for any car, especially with the thermal stresses
> of the turbos.
>
> Misfires when cold can be a variety of things, and would need further
> diagnosis.  Could be a sticking valve, air leak, failing MAF, knock
> sensor, etc.  Are there any other transient codes which would
> help narrow
> down the focus?  Over time, is the misfire code for the same
> cylinder?  Does
> it matter if it's wet or dry out?
>
> There's no such thing as a "piston misfire."  By definition
> the piston can't
> misfire!  The piston is mechanical, not electrical.  However,
> the code does
> say (somewhat cryptically) "cylinder misfire."  Perhaps you recalled
> incorrectly?  For what it's worth, these codes are fairly common as
> transient codes... but if the check engine light goes on, there is a
> definite problem.
>
> Good luck,
> Mark Rosenkrantz
> Binghamton, NY (and also enjoying the snow/cold)
>
> On Dec 6, 2007 10:59 AM, Aurangzeb M. Agha <ama-list at mltp.com> wrote:
>
> > I've noticed over the last few months that when I start
> driving the car
> > from a cold start and accelerate quickly, my check engine
> light turns on.
> > I've checked with a mechanic who ran the VAG and said this
> was a piston
> > mis-fire.  After four or five restarts, the light seems to go away.
> >
> > Now that it's gotten colder hear in the North East, I seem
> to see this
> > problem more and more.
> >
> > The car is a '01 S4, and has 89K miles on it.  Could this
> be a sign of the
> > timing belt starting to go?
> >
> > Thanks in advance.
> >
> >
> > Aurangzeb
> >
> > --
> > '01 Silver S4
> > _______________________________________________
> > Biturbos4 mailing list
> > Biturbos4 at www.audifans.com
> > http://www.audifans.com/mailman/listinfo/biturbos4
> >
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