So, my friend dropped by this morning with his bad ECU. I plugged it
into my 87, sure enough fuel pump cycled with key on, fast cranking but
would not start. He picked up a spare from me and left. I took the case
off the ECU for a look. I could see some heat damaged solder joints
where a big resistor was soldered into the main board. With my ohm meter
I determined that the resistor fed the big transistor that runs the fuel
injectors. I added new solder to the 2 resistor legs and took the ECU
out to the van for a test, with the case still off. The van fired right up!

My theory is this. He towed a trailer up to 5000' with a full load of
passengers as well. Since he had driven miles up the mountain with the
pedal floored the injectors were running at their maximum. That
overheated the aged solder joints on that resistor.

Also, after the "repaired" ECU was running with the case still off, I
flexed the circuit boards around and found I could get the engine to
die. I then added fresh solder to the leads on the 5 components mounted
to the heatsink. This cured the flex issue as far as I could tell. Maybe
this was the real problem that I thought I had fixed with just the
resistor soldering, who knows.

Mark

On the weekend I got a call from a friend in trouble. He had taken a
group of people up to a lake a few hours from home, using his 86 GL as a
tour bus. Everything went fine and they made it up the 5000' mountain
without incident. After unloading he decided to park in a different spot
and the van would crank fine but not start. Spark ok but no fuel injected.
....................
AAA called, made it home by tow truck.
Installed his spare ECU from his Westy under bench storage, fired right up!

Mark