~pino~

I have been experiencing a crank but no start condition erratically with my 98.5 1.8T qms 57Kmiles. After a cold soak, my car will tease me by cranking over just fine, but not starting. Usually after the 5th attempt it will start and run perfect. The only tell-tale sign is the check engine light on. After 4 normal starts the MIL disappears too. This happens about once a month. Running a diagnostic check on it indicates a code that has something to do with the fuel injectors not receiving a signal from the ECU. I've replaced the ECU thrice, 2 stage 1's, and 1 stage 2. The problem still exists.
Looking back through the forum, I see a few complaints similar indicating carbon build up on the valves. How do you go about removing such build up? Any ideas will be greatly appreciated!

BTW love the forum!

stevenknapp

Could you let us know what the code is and what it's real description is?

The injectors are nothing more than coils of wire. They can't report if they are or are not getting a signal. There are ways of determining if they injectors are ok, but I doubt the Audi ECU has this functionality.

Sounds like a possible no fuel or no spark problem. You could check the injectors and coils with a scope. If they are not firing check the crank/cam sensors as well. Is the ECU getting the signals it needs to know to fire the injectors. If it is, could an injector be bad? Could the harness have a problem?

I'm initally guessing a sensor could be at fault..but could be lots of things.

Carbon? Seems odd. Try some Techron perhaps.

~pino~

As this just occurred again yesterday, I will get the exact code when I take it to my service facility yet again