Tachometer doesn't work! :-(

[Phil Payne]

> Bad things are going to happen if you unplug the timing sensor if the
> RPM sensor should miss some teeth.  I wouldn't do that.
> The timing sensor is actually 62 degrees before TDC on Cyl 1.
> If the car starts, the hall sensor is working.  On later cars,
> I don't think anything bad will happen if it fails while the car
> is running.  Not necessarily true on earlier (MAC11) cars which have
> a bug in the cylinder counting code if the hall sensor fails.

Similar things happen on cars with one or more damaged flywheel teeth.  Flywheels with a single tooth broken off seem to be
remarkably common - I've seen three in about the last year.

Depending on where exactly the missing tooth isn't, the symptoms are somewhat different - basically all cylinders post-missing tooth
are retarded - but by how much?  Three half-teeth is my current theory.

--
  Phil Payne
  http://www.isham-research.com/quattro
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