Posted by Mike W. on July 06, 2008 at 21:28:29 from 75.101.11.141
In Reply to: OT - No spark on e28 535i posted by Nate in Pitt, from SLC on July 06, 2008 at 15:49:47:
Several things come to mind. It could be the ECU, the 059 unit on E28 vintage cars has a known habit of breaking solder joints on the big transistor that feeds the ignition. That would kind of make sense given the randomness of it. It could also be the main relay, that odd 5 terminal one with the center marked either 87 or 87b, but absolutely not 87a, that's the wrong relay and it wont run with it in there. Next on my list would be one of the reference sensors that pick up off the flywheel, they can go bad with age.
After that you're well into the could be's that are much less likely. It could be the AFM, or the coil, or the OBC relay...
Do the deed and register on Mye28.com, it's a good board and the right place for E28 help.
Mike