Audi Repair: Audi S4 starting problem, audi 100 s4, fuel pump relay

Question
I have got a problem with my Audi 100 S4 1991: After approx. 70 km travel without any problem I had to wait for the ferry and stopped the motor. When trying to start the motor turns, but do not fire. Audi service do not seem to be able to find the cause - to now they have used a week -   any proposals ?
Thanks in advance.
Jan Borst

Answer
I would check first if the problem is no spark or no fuel.  If the problem occurred so abruptly, I would assume a catastrophic failure of a component like the engine control module (ECM), ignition relay, fuel pump relay, fuel pump, could be a number of different things.  First you need to identify if the car has fuel going into the cylinders, and if there is a spark at the spark plugs.  Let me know,  Jan