Odd starter problem

[bmwtool]

So…

I just finished putting my m20 together in my 1988 325i after pulling the intake, replacing all the coolant hoses, fuel lines, etc. While I had access, I had my starter rebuilt as a precautionary measure.

The car cranked for awhile while the fuel system got up to pressure, then it started and idled perfectly for about 30 seconds. It suddenly started making a racket that sounded like the solenoid engaging and throwing the starter gear into the flywheel. I turned it off immediately, checked connections, made an additional engine to chassis ground wire from a jumper cable as a precaution, but it still occurs: The car starts immediately, then a second later the grinding noise again.

I was very careful labeling the wiring, and as I had my starter rebuilt locally, I got the very same one back, so there's no chance I have different connections on the starter.

So I'm stumped and I'd appreciate any help anyone could offer. I'm checking the archives, but I don't see this exact issue. I guess I'll be pulling the starter today just to be sure, and I'll be laughing at the irony of having rebuilt the damned thing to avoid just this sort of trouble.

[Seawolf]

Sounds like your starter solenoid is activating after startup.

Could be a problem with the ignition switch, unloader relays or the starter/solenoid (most likely since this has just been worked on).

Take a look at: http://wedophones.com/Manuals/BMW/19...g%20Manual.pdf

Page 1240-1

To isolate the problem, start the car and disconnect the Black/Green wire that connects to the starter solenoid. If the problem persists it's a starter/solenoid problem, if it doesn't the problem lies in the starter circuit.

If it's in the starter circuit, check the Black/Green wire for 12v after the car has started. If you're getting 12v then it could be a bad relay, you'll need to chase this back through the circuit to find the culprit.

Still thinking this could be a starter problem.

[bmwtool]

Thanks a ton for the advice and the link! Much appreciated! I'll tear into this after breakfast.

[Seawolf]

Oops.....my bad, I think the solenoid start wire is Black/Yellow not Black/Green.

It will be the thin wire that connects to the rear end of the starter solenoid with a spade terminal.

Sorry about that, I shouldn't be writing email before I finish my coffee.

[bmwtool]

Oops.....my bad, I think the solenoid start wire is Black/Yellow not Black/Green.

It will be the thin wire that connects to the rear end of the starter solenoid with a spade terminal.

Sorry about that, I shouldn't be writing email before I finish my coffee.

I got it sorted out, thanks to the wiring diagram, and it was my fault. I had the charging system lead on the post with the black/yellow wire, so as soon as the alternator spun up, it would fire the solenoid.

Thank you again for your help! I'm sure that wiring diagram will prove useful many more times! :up: