forum.audiv8.com Foren English Audi V8 Forum 92 V8 electrical problems.

Hi.
One of my Audi's - 92 V8 4.2 ltr auto Quattro has electrical problems and won't crank and if starter interlock relay is bypassed will crank but has no spark.
Car was going and parked over night.
Next day it would not do any think from key.
Starter motor is in good condition.
Suspect the problem is with security system/central locking which has imobillized car.
Have wiring diagrams for 1990 model but 1992 car if different.
Hope someone can help me with diagrams or hints to get car going.
Getting very Stressed !


Robert R.
Australia

Hi,
You can check the Flywheel positition sensor and the rpm sensor at the engine, when the flywheel position sensor is not able to send as signal to the ecu, the ecu do not know when it has to send the ignitionspark to the 1st cylinder,
the sensors are mounted,when you look from below the car in driving direction above the driveshaft on the left side under an guard plate, near the gearbox, when you remove the two bolts you can take out both sensors (thier mountet together on a braket). The electrical recistance must be approx. 1 k Ohm.

I hope i could help you.

If you have an original Audi alarm -system, it may be a Problem with the micro-switch inside the door lock. Try to unlock the car from the other door.

Guido,
Thanks for that information.
Confirms what i thought was the problem area with the security system.
Have to reassemble car and test door micro switches.
Stiil would like to get wiring diagram for security system and fault diagnosis to be able to disable factory security sysytem.

Thanks.
Robert Righetti

Hi Robert,

you may have some other troubles concerning the wiring diagrams because you are (propably) driving a right-driven V8 which has some things like the Audi 200 and some like the Audi V8. It maybe that the wiring is exactly the same like on a left-driven V8, but keep it in mind!

I don't know if you've already read out your error memory of the Motronic using the diagnostic interfaces located on the left side in front of the passenger seat, under the carpet. It's always a good point to start.

Anyway I can also imagine that there are problems with the security system although I'm not really experienced with the system.

Regards

Bastian