Hello Everyone,

I Replaced the A/C compressor and accumulator/drier on my 1985 740 B330F. In the process I removed the alternator for access and replaced the positive battery cable. The car now runs like crap. Idles rough and has almost zero power as if it’s missing. I don’t know if I bumped something or it’s just coincidental.

Checked the FAQ and here’s what I've done so far.
1. Checked knock sensor connection and disconnected it and car stalled.
2. Pulled AMM connection and car stalled.
3. Battery terminals and battery ground cable appears fine.
4. Checked resistance of each fuel injector – all are normal.

So I started thinking ECU. I believe my car has the LH2.2. I really don’t know much about the injection system and sensors on this car but I do have a spare ECU from a 1988 740 B230F manual transmission that I would like to try in my car but the part numbers are different. The spare is a 0 280 000 554 and mine is a 0 280 000 511.

Anyone know if the 554 will work in my 740 with the 511?

Any thoughts and suggestions would be greatly appreciated!

Michael
Melbourne, Fla

1985 740 460k (original motor)
1988 780 Coupe V6 190k
1989 780 Coupe V6 149k (parts car)
1992 745 199k