Coil Failures - Letter from Audi

[Ti Kan]

Huw Powell writes:
> >  Operating the car with a failed coil will
> > cause unburnt fuel to enter the catalytic convertor, and can
> > lead to convertor failure too.
>
> While on the one hand I agree with you, somehow my wishful thinking
> makes me imagine that the ECU might be smart enough to turn off the fuel
> to the cylinder that isn't firing?  Yeah, right...

Hmm, you might be right.  Years of "CIS conditioning" had me thinking
otherwise.  The new Motronic ECUs are indeed very smart.  If it's capable
of detecting a failed coil (which apparently it does, because it will
trigger the auto-check warning and an appropriate DTC), it could simply
stop injecting fuel in that cylinder.

So in the event of a coil failure, maybe the driver will indeed simply
notice rougher running and reduced power, but otherwise no additional
harm done.

-Ti
2003 A4 1.8T multitronic
2001 S4 biturbo 6-sp
1984 5000S turbo
1980 4000 2.0 5-sp
--
    ///  Ti Kan                Vorsprung durch Technik
   ///   AMB Laboratories, Sunnyvale, CA. USA
  ///    ti at amb.org
 //////  http://www.amb.org/ti/
///