Kirby said:
If it has Bosch ignition ( I think it does) it probably has a transistor refered to by Bosch as the power module. It connects between the ECU and the coil, and directly to 12 VDC. It sends 12 volts to the coil when pulsed by the ECU. These things go bad exactly as your problem describes - the heat sink mounting base corrodes and causes it to fail. Assuming your car has this item, did you check/change it?
I know this one from personal experience with an '87 Volvo with Bosch ignition.
I was just going to say "hey you copied what i said" but I forgot, I never posted what happened to me.
Except, the transistor for BMW's that send the pulse (at least early-80's to now) is actually built into the ECU. There is no "power module" either - there is constant +12v to the coil through the main relay, and the pulse is generated by controlling the negative 12v (through that transistor)
2 weeks ago, my friend and I were driving to hershey for a bears game, turned into the parking lot and the car died. Dad towed it back home (rented a trailer), and found out the coil went bad, and when that went bad the ECU fried. You can see the NPN transistor, FRIED.
BTW you sound pissed off - blaming the car for 'nearly loosing your job' is stupid - I would blame it on poor troubleshooting. My ECU is found in THREE different cars, E24 635csi (only 88's and newer), E32 735i, and E34 535i. I paid $75 and found it after about an hour of looking. You can UNDOUBTEDLY get an ecu (I believe the last digits are 173) for under $50. After all the stuff you replaced you should have a very smooth running car. You're going to be hard-pressed to find a more reliable car than the E30.
![[cheers]](/images/smilies/icon_smile_cheers.gif "Cheers [cheers]"){kind=icon}
[bmwdance]