Finni91

I have a 91 audi 90 20v 7a and one day she wouldn't start. I checked to see if I was getting spark and was not on #2 and #4. I checked to make sure the hall sensor was getting the correct power and it was. I tried a different distributor and still no changed. I swapped the ecu from my parts car and now I get spark on #4 but still nothing on #2. So Im assuming my ecu is shot? Whats my next step? Is there anything I can check before I try to find a new ecu?

yodasfro

I think you need a new cap and some plug wires. Do you have the wires in the correct order on the cap?

Finni91

I've tried multiple caps. Wires are in the correct spot.

IdahoDoug

I don't know the numbers but you can check the resistance of the wires. Or switch wires around and see if the fault follows the wires. If its getting colder where you are, older wires with faults will get "faultier"

Doug

Finni91

Ive swapped wires and test straight from the cap. No change. Its cold here now and nothing has changed.

Hybrid_Hatch

have you tested spark outside of the chambers? IE have you pulled the plugs and tried to have it spark against something in the engine bay?

Finni91

Yes multiple times. There is absolutely no spark coming from #2 and #4. Like I said, I've tested straight from the cap.

x19

How about, you have a open electric wiring or power at the injector?
You have to check the voltage or power at the back of ECM that you need to do I think. Good luck and Happy Holidays. x19

Ps, What is your ECM # ? I may have.