anyone with a 633 CSi out there?

[bmw4astrid]

I am curious to talk to other owners of 633 CSi. I have a 1978 with original 140,000 KMS (about 87,500 miles) and seem to have the weirdest (but most often harmless) problems...

[The Beastmaster]

I used to have a 633csi years ago. Now I have a '79 635csi and probably experience the same probs as you.

[bmw4astrid]

did you or do you have problems like:
the radio stops when you brake, but starts again after a few seconds. Not every instance of braking, but more often if the headlights or the windshields wipers are on at the same time thwe radio is on.

I now seem to have an electrical problem with the fuel pump. This one is more bothersome: the car won't start. But it has been determined the fuel pump in itself is ok, theproblem seems ot come from an electrical thing, but I don't know what yet.

[The Beastmaster]

Radio
The brakes, radio and headlights are all on the same circuit. Other BMW guys have the same problems. My radio display dims at times, but nothing else. How old is your battery and how is your charging system? Is your AC on at the same time? If your battery is old, that may be the problem, or the alternator.

Fuel pump
Did you check your fuel filter? It may be clogged or filled w/ debris. Also, considering the age of the car, you may have a lot of sediment in the tank that may be fouling the filter/pump.

Are you sure your fuel pump is running when you try to start the car? Does the car refuse to start when the engine is cold or hot? If it doesn't start when hot, it could be starter related. Also, your ECU may have gone bad. It is above the glove box covered by a sheet of vinyl. Try tapping the ECU when the car doesn't start. If it starts, you may have to rebuild your ECU or if you're the gambling type, buy a used one. I had my ECU rebuilt and it ran @$250.

[BMW635]

I had a similar problem on mine. At first I thought it was the fuel pump relay behind the fuse box. That might be something to check. Mine turned out to have a loose connection that ran from the fuel pump relay directly to the battery. Tightened it down and it has been good to go ever since. Just an idea! Good luck!

[BMW635]

You might want to check with the guys on the 6 series board at http://www.roadfly.com They can be pretty helpful. If you're not familiar with the site, when you get there just click on message boards and go to 6 series.