Weird MC engine problem
quattro at isham-research.com
Fri Aug 9 23:20:05 EDT 2002
> > > Well, it must restart eventually. How long does it behave like
> > not wanting
> > > to start?
> > Variable - roughly two to five minutes.
> That's a bit fast for a fuel problem like flooding.
It's not flooding. CO stays constant right to the end.
> > > When it will not start, does it have spark? It might be a shorted coil,
> > > that kind of sort of works until the cylinder pressure goes up,
> > whereupon it
> > > shorts due to the increased heat load on the coil. After it
> > cools, it works
> > > again. This is, of course, a real WAG!
> > Spark is normal.
> Hmm, still does not rule out a problem with spark under compression.
> > > Have you swapped the ignition module for a known good one? (I'm
> > assuming the
> > > MAC-14 MC still has a separate ignition module, like the MAC-11 system)
> > Yup - swapped the coil pack with another car. Symptoms stayed
> > with the car.
> So much for the "short" (or "long") on the coil theory :-)
> > I forgot to mention - on a significant number of th efailed start
> > attempts, the engine kicks
> > in and runs backwards for three or four revolutions.
> Interesting. Did you power wash the engine? You may want to check the
> distributor, especially the cap. I've seen water or other foreign material
> in the cap. I've had these cars idle fine, but buck and stall under load or
> increased rpms. Foreign material can cause all sorts of crossfire events,
> which might explain the backwards running, and the stall.
Nope. No wash and the distributor has been out and cleaned so many times ...
The only oddity - at some time someone has scratched a 'new' alignment mark in the top of the
distributor body wall. It's about 5 degrees advanced from Audi's mark.
> You're not off by one on the plugs, by chance? Maybe swapped two leads? I
> suppose it might idle in such a state, though I have not tried this.
Firing order is correct.
I should mention that the car is at a turbo specialist - Turbotronic in Woodville. It has
every diagnostic device known to man hooked up to it.
+44 7785 302 803
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