I have also suffered the failure of my ECU on a '84 Digijet 1.9 litre Westy.

When it happened, it locked the injectors open (I found out later)and as a result , after running for a few seconds, the engine quit and would not restart.     
I did not know the injectors were open and I continued to crank the engine until the battery was dead.   I jumped it off and tried in vain to start it.   
I replaced several ignition components and did several tests,over several days, each time cranking and cranking, to no avail.
Then the engine did finally start.    It ran very rough and when I revved it, It spewed oil out of the exhaust pipe and smelt of gas.
I immediarely shut it down and checked the crankcase and found it full of oil and gas.
Then I made a couple of phone calls to a parts dealer in Michigan who told me that this happens when the ECU fails.
I drained the oil, put in fresh, borrowed a known good ECU and it cranked and ran fine.           I sent the ECU  to Darrell Boehler but he has not been able to fix it.
Later on I had a bucking problem and thought the ECU had failed again.
However, it turned out to the wire going to be the Aux Air regulator under the airbox which was going to ground and depriving the injectors of their ground through the ECU.    This wire is connected to the injectors with a hidden connection inside the wiring loom.    It was very hard to find.       
I rewired the aux air valve to get its power from another source and havent had a problem since.
Just wanted to share my experience with the group, and it may be relevant to your problem.

Good luck with your van,

Steve Cotsford