MAC11 update

urq urq at
Tue Sep 2 21:43:38 PDT 2008

... gotta love the supportive way folks operate on the "quattro list" these
days ... 

The earlier post was spot on ... rotating the dizzy will not change the
ignition timing on an MC engine ... the engine timing is based on the
variable reluctance sensors and reference features on the flywheel.  The
Hall Sender in the dizzy just tells the ECU whether or not the reference
mark is indicating an even or odd cycle of the engine.  If the dizzy is
rotated far enough one way or the other the hall sender will not align with
the flywheel pin when it passes the reference sender and the engine will not

Based on your symptoms I'd say the flywheel is where you need to focus.
Best case you have a problem with the "speed sensor" ... the one which
senses the teeth on the flywheel.  Worst case it may be that your flywheel
is damaged in a way that the speed sensor is having problems reading the
teeth as the flywheel spins faster.  Did you have any recent problems with
the starter?  ISTR others reporting the engine misbehaving in the same RPM
range with a damaged flywheel.

To test the VR sensors you may be able to swap the reference and speed
sensors (it works on a V8, and should work on an MC, but I have no BTDT) ...
swap them at the bellhousing and the electrical connectors.  To see if the
flywheel teeth are messed up you can pull the starter and spin the motor by
pushing it in gear or using the Audi crank tool.

Steve B
San José, CA (USA)

-----Original Message-----

Thanks for trying, in spite of the people who actually know what they 
are talking about saying it couldn't be an issue.  It obviously is.

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