Re: New Audi Fan with history on 1988 Audi 90

[quk@isham-research.demon.co.uk (Phil Payne)]

In message <199910210240.WAA19788@audifans.com> "Walt Dwarnick" writes:

> The problem is that the car seem to go into a limp home mode where the
> engine controls appers to ignore the ECU computer fuel control and the idle
> drops to about 300 rpm.  When I shut the car off, to reset the system, and
> then restart, the engine speed returns to normal.

> I don't think that it is the Idle Stabilization Valve. I tried resetting
> the air flow potentiometer, which helped for a while, but the problem
> returned.  When I pull off the connector to the air flow potentiometer, I
> get this same idle drop effect.  Could be a short.  I plan to focus on the
> air flow potentiometer, because pulling off the connector to the air flow
> potentiometer really simulates my problem.  So I will have to definitely
> eliminate a short as the cause.

It could be the circuit between the ISV and the controller (double-width
relay under the dash) going open.  If the controller sees a break in the
circuit to the valve it will stop operating it until the ignition is
cycled.

--
 Phil Payne
 UK Audi quattro Owners Club
 Phone: 07785 302803   Fax: 0870 0883933