Re: Interesting ur-quattro problem

[Orin Eman <orin@WOLFENET.com>]

> Those three wires (attached to the inlet manifold) go into the ECU wiring 
> harness and metamorphose into around thirteen grounding wires for the ECU and 
> some of its bits and pieces.  It seems that some of the ECU's sensors are so 
> marginal that the voltage drops in chassis bonds are significant.

Funny thing is in the MAC11 computer, all those grounds that go into the
computer are then tied together immediately... you'd think that they would
use some kind of differential amp to cancel out any potential on the
engine or main computer ground, but no.  For example, I measured my
O2 sensor between the sensor wire and the sensor body, it was doing its
thing in the .08 to .88 V range.  Fine.  At the computer, it showed
-.08 to .7 V!  There was a significant difference between the engine
ground and the computer ground!

Orin.