Weird MC engine problem

[Phil Payne]

Before I start - this car is a dog.

It's an Audi 200TQ (5000) with an MC engine run by a MAC14.  It was off the road for an
unspecified period, believed to be long, and then had some kind of electrical event.
Basically every component on the auxiliary relay panel with a transistor in it was fried.

So were a few other things - like the central locking pump ...

The ignition switch is also extremely suspect and the tachometer and trip computer are dead.

Anyway - I've gutted and rebuilt the electrics.  The diagnostics run and the ECU stores no
codes.  The car will start and idle from cold - duty cycle is 50%ish at idle, ISV current 440
milliamps.

If you try and put any appreciable load on the car, it dies instantly and won't restart.  At
this time, an attached code-pulling LED illuminates permanently.  If you cycle the ignition,
it comes back on with ECU power.

I've swapped the ECU and coil pack for known good ones and tested the swapped ones in another
car.  Also the control pressure regulator.  The fuel pump has been swapped - pressures and
flows are within specification.

--
  Phil Payne
  http://www.isham-research.com
  +44 7785 302 803
  +49 173 6242039