Mark, did you vaccum out the old solder? I'm curious because I have a
small stack of ECUs in the gai-rage.
Miguel

I have not failed. I've just found 10,000 ways that won't work.
  - Thomas A. Edison

On Thu, Apr 15, 2010 at 2:11 PM, mark drillock <mdrillock@cox.net> wrote:
> 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
>