Starter motor wouldn't stop!

[redhatpat]

This happened last Monday morning, but I wanted to get some feedback on what others thought would cause this problem.

I started up the car (1990 325i) normally, but heard a really loud shriek/whine coming from the engine area. I first thought it was a bearing in the alternator or power steering pump finally going bad in a big way. But after a short while (maybe 30 seconds), I realized it was REALLY noisy, much more than I could continue driving with and it wasn't going away. So I pulled back into my parking spot, and turned off the key. The engine stopped running (I now realize), but the starter motor kept turning and was still engaged! I tried stalling the engine in gear, but it kept pulling forward, just got bogged down a bit. At this point I realized it wasn't the engine, but the starter motor that was running. So I put the parking brake on, got out (holy shit, this shrieking was loud!) and disconnected the battery to finally get the f**ing thing to stop.

Fuck!

I got my daughter out of the back seat, and back inside with my wife, then went back outside to do some diagnostics. I put the battery post back on, battery was still ok, and the starter didn't start up again, whew. I could smell "electrical motor working hard" smell, but didn't see any burnt up wires. whew!

1) There is a "battery" post on the starter motor. It was hot (had 12V to it), even with the ignition off. Is this normal? Not shorted out? I'm guessing yes.

2) Since I've owned the car for about 6 months now, and its the first time its happened, I suspect it was the starter motor solenoid getting stuck in the run position, and since the battery post is always hot (fucking brilliant bmw!) the motor just kept turning and this wasn't caused by shorted out wiring. Correct?

I'm now keeping a wood window scraper in the passenger seat so if it happens again, I can jump out and knock that son of a bitch starter motor solenoid in hopes of disengaging it. I don't want to disconnect the battery again if I can help it. The computer had to re-learn to idle, which was a pain in the ass.

Any ideas if this is what happened? Has anyone else had this happen to them?

Freaked the shit outta me, I've seen cars fail in all sorts of neat ways, but this was a new one to me.

[Rigmaster]

1) There is a "battery" post on the starter motor. It was hot (had 12V to it), even with the ignition off. Is this normal? Not shorted out? I'm guessing yes.

2) Since I've owned the car for about 6 months now, and its the first time its happened, I suspect it was the starter motor solenoid getting stuck in the run position, and since the battery post is always hot (fucking brilliant bmw!) the motor just kept turning and this wasn't caused by shorted out wiring. Correct?


Any ideas if this is what happened? Has anyone else had this happen to them?

Freaked the shit outta me, I've seen cars fail in all sorts of neat ways, but this was a new one to me.

Haven't had this happen to me on an e30, but I've seen it on a couple of Ford vans when I worked for a delivery company. It's basically the starter solenoid sticking- easiest cure is to replace the starter. You could replace just the solenoid (if you can find a new one), but I'd just stick a good used starter in there- or go with a new (probably "rebuilt") one if you prefer ($$$$$).

I would suggest taking care of this ASAP, as it will likely happen again in the near future.

BTW, BMW is not alone in this wiring for the starter, about 95% of cars on the road use a similar wiring setup for their starters. Only some older Fords- like 60's and 70's, have a starter with a separate solenoid switch mounted somewhere under the hood- not directly on the starter. But even Ford has been using the starter mounted solenoid for many years now.


Bret.

[AdamF 88iS]

The solonoid is sticking. Replace the starter. The starter always has positive because thats where the battery + cable runs directly to. The solonoid itself acts as a relay to engage the starter motor when you turn the key. Don't shit talk the system when you don't fullly understand it; this is the same system used on pretty much every car on the road today.

[redhatpat]

Thanks guys, that confirms what I was thinking. I'm not looking forward to replacing the starter. From everything I've read since this happened, replacing a starter is a PITA. True?

Adam, I'm not shit talking a system I don't understand, I'm just venting - I know most cars are like that.

[AdamF 88iS]

Thanks guys, that confirms what I was thinking. I'm not looking forward to replacing the starter. From everything I've read since this happened, replacing a starter is a PITA. True?

Adam, I'm not shit talking a system I don't understand, I'm just venting - I know most cars are like that.

The top bolt can be a pain if you dont have the tools to reach it. Other than that it's not a bad job.

[mspiegle]

If for some CRAZY reason this doesn't fix your problem (and it should)...

I had a problem on my 928 where some oil was leaking on a wiring harness and ate through the insulation. The solenoid starter wire was touching another hot-wire, and the starter would not disengage until you unhooked the battery. I'm sure this is an extremely rare possibility, but thought i'd throw it in there...

[redhatpat]

The top bolt can be a pain if you dont have the tools to reach it. Other than that it's not a bad job.

Well thats good to hear. What sort of tools are needed? Any more "bmw special" tools? And does the intake manifold need to be taken off, or anything else disassembled to remove it? Can I take it out from above?

Thanks!

[AdamF 88iS]

Well thats good to hear. What sort of tools are needed? Any more "bmw special" tools? And does the intake manifold need to be taken off, or anything else disassembled to remove it? Can I take it out from above?

Thanks!

13, 10, and 8mm for the wiring. 17mm socket and wrench for the bolts. Long long extentions for the top bolt. Manifold doesn't have to come out. Flexible socket for this would help too.

[lordofthewaters]

Starter

17mm? Mine was a 16mm for the mounting bolts. I guess it could've been changed before. Anyway if you're one of the lucky guys with an air tool setup, I HIGHLY recommend using an air ratchet for the to bolt. I could get a ratchet to well.....ratchet. Not enough room, even with my heater hoses pulled back.

[NC325iC]

happened to me once, ended up being a peice of metal crossing two of the starter terminals. maybe you should check that first...