Art, and list!

I had this behaviour once, and in my case it was the connectors to the DLS that were corroded, which resulted in missing or badly timed sparks. Just try unplugging and bypassing the DLS, and see if it makes a difference.

The DLS (Digitale Leerlauf Stabilisierung /Digital Idle Stabilizer) is the white or black box sitting on the left hand firewall. It has two three-pole connectors coming in at the bottom. They can be removed and mated, thus bypassing the circuit. This circuit tries to control the idle rpm by adjusting the ignition timing. If this circuit is not working properly, the engine can be very difficult to start.

>started.  Initially the problem was a refusal to start despite good cranking
>- at the time I am pretty sure that I heard the fuel pump come on when I
>initially turned the key to the run position.  Subsequently, it has started
>and run after a normal amount of cranking, started and run after a lot of
>cranking, refused to start after cranking forever, and died once started.
>