I need some technical help. My 85 635 CSi was going down the highway when the following happened: 1.) the aftermarket radio made the sound it makes when the ignition key is removed 2.) the car started loosing power, so I pulled to the side of the road 3.) I had to feather the gas just to keep it idling (it sound like it was firing only on ONE cyl.) 4.) I turned the headlights off, the car evened out and idled fine 5.) Immediately the service indicator lights went red and the word "inspection" showed up on the SI pannel (note: this happened right when I turned the lights out). I tested the voltage at the alternator while running, it was just about 13 volts, a little less. I tested it later and it was about 12.6 or so. I took the alt. out and brought it to a rebuilder, assuming it was going, but he bench tested it and gave it a clean bill of health. I reinstalled the alternator and the car is running. Now I'm a little nervous about driving it any distance. Any advice?? Mark.
I have a 535i which is esentially the same drivetrain/electric gear. I would inspect the battery cables, both positive and ground; disconnect them at both ends, clean all connections (I use DeOxit to clean electrical connections) and reassemble. Have you replaced your main relay? In these cars at this age they are considered maintenance items and are really cheap insurance (I actually replaced the main AND fuel pump relay) You can also take a look here to have a better understading of what might have happened. Another area to look at is the ECU as it might have cracked solder joints. (This website has a pretty detailed explanation). Good Luck!
Thanks for the tips. Yes, I guess I've considered the relays - thanks. They had been replaced at one time, but I have a bunch of known good spares. I hadn't thought of the battery cables, though. I think the ECU is fine, but I can pull it and check out the solder joints. The car's running fine now, but until I can figure out what really happend I sort of don't trust it. Mark.
