I have a 1974 E3 Bavaria with about 147,000 miles on it. I've owned it since new. Yesterday it started fine. I parked it for 45 minutes and came out to start and nothing. Lights on dash came on, interior overhead light on, headlights worked, so battery ok. Wouldn't crank, click or do anything other than the electric fuel pump was humming. I came back at the end of the day, and it started right up as if nothing happened. I'm thinking maybe its a relay or something, but I don't know if it has a little relay or if it just has the solenoid that's attached to the starter. Any ideas? Thanks.
Suspecting solenoid. Get a helper to give the starter body a "love tap" with a hammer or something while you attempt to crank the next time that happens. If wakes up and cranks=starter solenoid is bad.
Thanks. I've considered that, just never happened before. Do you know if there is a separate relay for the starter. There are several "cube" relays for lights, etc. in the engine compartment near the battery, and I didn't know if the starter has one of those or not. It would be easy and cheap to just replace one of those as a place to begin. I"m trying to avoid being stranded somewhere and finding that whacking the solenoid isn't the solution. Thanks.
If a Bavaria starter is similar to my former 320i, that's the first indication to replace the starter (the frequency of it sticking will only happen more often going forward). Looking at realoem.com, it appears a solenoid may be replaceable separate from the starter, although with a starter at only $100 bucks (via autohausaz.com) vs. just the solenoid for a bit over $100 (bavauto.com, special order part, meaning available only from BMW), there would be no reason to not just swap out the old starter for a new one. http://www.autohausaz.com/search/product.aspx?sid=yjgz2kidfxyzejbtzewsfqyl&partnumber=12411272150 Starter part # off realoem.com: 12411272150 diagram: http://www.realoem.com/bmw/showparts.do?model=6213&mospid=47247&btnr=12_0950&hg=12&fg=25 Solenoid: 12411354579 diagram: http://www.realoem.com/bmw/showparts.do?model=6213&mospid=47247&btnr=12_0968&hg=12&fg=25 Start at the beginning of realoem.com to make sure you have the right model in, might be best to input your car's serial #, then you'll have the right part numbers. Starter is under "Engine Electrical System". You can search part numbers on autohausaz.com and bavauto.com for comparison purposes, among others. The above part numbers were for an E3 3.0S Bav, production month of 4/1974. You may want to pose your question on mye28.com as well, there are likely many there experienced w/ your specific model. Every time I had a starter do what you describe, it wasn't anything electrical, just age & mechanical wear; pre-emptive replacement would keep you from getting stranded, at least due to that specific issue. It's possible it started up later in the day because it was enough warmer for the solenoid not to stick at that temperature; eventually it will get to the point that no amount of hammer-tapping will allow it to work. Not familiar with Bavaria electrical systems, although I'd guess there's some sort of cut-out relay that cuts power to everything except the ignition system (presumably, fuel pump or pumps & spark plugs) & starter. It's a guess, but I'd think if the cut-out relay was bad, the symptom for that would be that power to auxiliary systems was not cut during starting, not that it wouldn't turn over.
I had a very similar issue, almost exactly like yours and finally solved it by changing the ignition switch and harness. I bought the part new from Bavauto Part# 61 32 1 357 380 - not cheap $150 but it was new. No more problems starting the car.
