Over the last several days my wife's '93 325i (with 2 zillion miles on it) has suddenly quit on her several times (usually in the middle of the road!). It sounds like a loose battery terminal or electrical short somewhere because *everything* goes out - lights, emergency flashers, panel lights - everything. Of course, the engine won't turn over either when this happens. Then, for no apparent reason, everything comes back on, car starts, and off she goes. I haven't been able to reproduce the problem. The battery is fairly recent (1 year or so) so I doubt it's an internal short and all connections look good.
A search here in the forums mentions problems with the main relay as a possible place to look - but I thought that relay only fed the ECU (which would explain the thing quitting - but what about everything else?). It seems to be a total disconnect problem because the clock loses date, time, etc. and the radio presets get blown away as well.
Any opinions on where to look first?
Thanks,
Bill
I have referred people to my previous post several times...
http://forums.bimmerforums.com/forum/showthread.php?t=185735
Thanks Mike - but unfortunately it's not going to be that simple :( The obvious battery terminal/grounding links appear to be just fine. And if it was a major short somewhere, I'd expect at least a fuse or two to give out, and that's not happening.
Any battery experts here that have any experience with internal battery shorts that are intermittent? Any way to tell for sure (short of replacing the battery?)....
Finally, any opinions on the "main relay" idea? Feasible? I just wish this could be reproduced somehow in a repeatable fashion - 'cause it's definately a safety problem with the car just quitting whenever and wherever it wants to - like in the middle of heavy traffic!!!
I've seen this type of electrical problem before in two different cars. One a Scirrocco that my friend swears was possesed by a demon because of the erractic electrical gremlins. The various electrical items would turn them selves on/off at random with no particular order, and then the car would run fine again with no symtems. The problem was battery ground itself, when I grabbed it was able to move enough to kill/induce to much resistance to the main ground for the car. The second was my former mustang, I had become overzealous with the deatail job on the engine after replacement and painted the back side of the engine ground strap, boy thar was a hair puller to figure that one out. So I would throughly check all ground straps and battery/main chassis ground for security, and run a resistance check on them(still attached) to start. Without a good ground your cars electrical system will do so crazy things and rally make you wonder what the hell is happening. I hope this helps some.
Oh, one more idea, check the fusible links for the car, I had a GTI that had them under the battery tray and over time the acid from the battery ate its way throught the insulation and corroded them to the point the car quit one day. I'm not sure where they are on your car but I have not seen a modern car without them. They could be chaffing against something enough to cause the temporary condition you descibed.
