S6 running problems, continued ad nauseum

[Kneale Brownson]

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Just thinking here.  There's no distributor, right?  what triggers the
firing order?  Is it something from the ECU that specifically says, Fire
One, Fire Four, etc.?  Is this done over separate bits of wire for each
cylinder?  Maybe there's a problem with this order path because of a wire
that grounds when it warms up?????





At 05:37 PM 12/15/2001 -0600, Steve Marinello wrote:

>Having obtained an ignition control unit/power output stage device for my S6
>avant ( at a most reasonable price with the assistance of a list member), I
>had hopes that the intermittent missing problem I had would finally be put
>to rest.  Unfortunately, I have to report that there was no change.
>
>The car came to me from KAR with Hoppen/MTM software mods, RS2 exhaust
>manifold and RS2 injectors.  The car exhibited widely intermittent episodes
>of running on four cylinders, with the culprit always being #4.  An Audi
>dealer tech, the only one I let work on the urq, checked the system and was
>almost sure it was a bad injector, as everything else checked out.  The coil
>packs had been replaced less than 20k earlier and the dealer records seem to
>point to this problem existing way back and never being fully resolved,
>although it would go away for long periods.
>
>Everything appeared to be firing correctly when the miss occurred and
>disconnecting the injector lead had no effect.  Coil packs were swapped to
>no avail.  The injectors were replaced with stock units, as the car appeared
>to be running rich most of the time.  That was a positive step, but
>unfortunately it did not cure the intermittent missing.  New plugs and new
>connectors were also installed, again, without resolving the problem.
>Grounds were cleaned and reattached.  The Motronic box was pulled to make
>sure all the connectors looked clean and that nothing was apparent down
>there.  I really had hopes for the stage device.
>
>All I can come up with now is a problem injector lead to #4 (but it was
>firing when the miss occurred and it was disconnected from the injector) or
>a broken valve spring hanging up periodically.  It stinks to h*ll when it
>misses, so there's plenty of gas there to overload the cats.  The fact that
>it is always at #4 sort of precludes the MAF or other general system
>problem, doesn't it?
>
>The car also bucks/misses badly in 1st and 2nd when it seems to be in the
>mood to shut down #4 completely.  An intermittent miss is apparent in the
>idle.  Sometimes, you can trigger the full five minus one equals four
>cylinder running by getting into the gas and accelerating in 2nd, 3rd or
>4th.
>
>I'm approaching a sense of despondency over what should be a very enjoyable
>car.  Is this what I get for having a dependable urq?
>
>I'm on my knees...no, actually flat on my back...can the brain trust of
>these lists please provide further assistance?!
>
>TIA,
>
>Steve
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