Hey everyone. I bought a 1991 Audi V8 5-speed 3.6L about a month ago. I've been working on it trying to make it run. It hasn't run for 5 years and has been worked on by tons of people trying to fix it in that time. With this website and the wiring diagrams I have made a lot of headway but I need a little help still.

Initially the car would not trigger the ECU. I found the power to the ECU from fuse 29 to be broken somewhere. By jumping it, I am able to get the ECU alive and read codes off of it. I also had a dead fuel pump which I am replacing with a Walbro GSS341. The fuel pump relay does work and has power but is not triggered by the ECU. The timing sensors are both okay and I do have spark. The engine runs on starting fluid. It is not triggering the injectors though. The injectors DO work, tested by jumping them. Also bypassed the fuel pump relay to supply power to the injectors and still nothing.

I only have one code 2121 for the Idle Switch. When I try to do the output test to trigger the injectors, giving full throttle does not activate the test even though the correct code for injector one is blinking on the CEL.

Can the idle switch stop the engine from starting? And what can I do to fix it?

Thank you everyone for the help you've already provided with this forum. Hopefully I can get this cool and rare car back on the road.

Na Ja, so ist es.