Audi Coupe

1990 Audi Coupe Electrical / Lighting Systems Won't Start  No pattern

This is a coupe quattro 20V DOHC just to be specific. I've checked the fuzes, they're good, I replaced the distributor, and the cap and rotor, so that is good, and when I turn the key it will turn over but there is no spark, (there is slight RPM though). Also, it has new spark plugs. A guy at the shop helped me troubleshoot, and he thinks its either the ignition coil or the computer. Any thoughts?

Here are the procedures to check for a no start on a fuel injected engine.It will require a couple diagnostic tools that you do nt most likely posess,but may be able to obtain through a tool loan or rental program at many parts stores.

In order for an engine to run it needs the following:

1. Fuel (Fuel pressure gauge)
2. Spark (In line Spark tester)
3. Injector pulse (Noid Lights)
4. Compression

You must determine which one or more is missing to proceed.

You can reduce the troubleshooting by spraying carb clean or a little ether into the intake throttle body to see if it attempts to start.If it does, then there is a problem with fuel delivery and not ignition.This will tell you whether or not there is fuel being delivered and isolate the issue to fuel pressure/delivery or injector control circuits.

You can check for spark at a spark plug wire while cranking with a flat tip driver or in line spark tester inserted into the plug wire boot and placed close to any metal part on the engine besides the fuel system lines and fittings or just plugged back onto the spark plug if using an inline tester.


To check injector pulse you will need a noid light set which can be purchased at your local parts store or through tool rental or loan programs as mentioned above.(Picture below)

To check for air just make sure the air filter is not totally restricted.
To check compression,remove spark plugs,install compression gauge and crank engine.Repeat on all cyls,record readings.
Please post back with your results so that we may help you through you car trouble.

You can remove the igntion coil and most autoparts stores will test it free of charge (Autozone, Advance, etc.- call ahead to be certain). Also remember you need power to the coil, make sure there is key on power available to coil (one terminal will get positive voltage with the key on and lose it when the key is turned off)."

Its getting air and fuel like it should. Did you read what I wrote?

I did, someone else left a note before I did and then the question was released and I picked it up. My message was about testing the coil.

Thanks Doug, mightymikes cookie cutter answer kinda pissed me off. I took it to autozone and had 'em run an ohms check on it; everything seemed good except that the primary lead wasn't registering any ohms. They weren't able to hook it up to the actual tester they had there, though. So I don't know what to think.

It is tough to say, but if the primary is open there is a problem, the only question is what were they actually measuring.

If you have a Parts America, Advance, or Kragen autoparts store they may be able to test the coil. I notice they sell carry several brands and should (well hopefully) have the proper test equipment.

Other than this test for key on positve voltage to the coil and test to see if the negative (on/off) is being triggered. If its triggering and you have power the coil must be bad. The fact that your tach shows rpm's while cranking indicates the distributor should be functional.