1995 M3 Starter Relay Minimum Coil Voltage

I am troubleshooting why my M3 will not start:
I am not sure what the input voltage to the starter relay needs to be.
I located the Starter Relay, pulled it out and tested it to confirm that when given 12 volts, the output contact toggles states. However, when I put the relay back into its socket, I didn't hear or feel it clicking at all. Tried turning and off the key. No change. Next I measured the voltage in the socket at terminals 85 and 86. They never changed no matter what the ignition key position, but also never went over 10.8 volts. I am not super familiar with this circuit, but I expected a higher voltage, and one that would drop to zero when the key was in the off position. I am completely new to this forum, and am really trying to figure out how to avoid spending money I don't have getting my favorite car back on the road.

Background:
Over the last few years, I have suspected that I had a vampire load because when I would stop driving my car for a bit, it wouldn't start. I replaced the battery about once every 8 months and that kept me from figuring out what was happening. Finally, I went to get another battery, and the sharp guy at O Reilly's insisted my battery was fine. When I swapped the M3 battery into my Wagon, it started it no problem. I became a believer. This same guy had suggested that I inspect my after market stereo installation. When I pulled it apart, it was obvious that who ever did it was not too careful. I disconnected it, and immediately, the car was able to start. I left the car stereo disconnected, and have yet to redo it. At this point, I paid the registration on it, and got ready to have it smogged. After a couple more weeks... it wouldn't start again. The only way I can start it is dropping the clutch.

Today I took out the glove compartment, and found the starter relay. The testing I did on it is above.

what is the battery voltage?? 10v is not going to start the car. get that up to spec first, then start chasing down the rest of the symptoms....



df

Had the car hooked up to charger during the testing. I tested the relay by connecting leads to the positive post in the engine compartment and some ground. It was just under 13 volts there at the time.

Since I was able to measure over 12 volts in the engine compartment, I am assuming that the battery was charged enough while I was measuring the voltage at the starter relay. Sounds like my next stop in trouble shooting is the ignition. Do you concur?

i would check the starter solenoid with a test light. yes, it's tight, but if you get no power to the solenoid when cranking, then you need to follow back from there.

did you happen to try jumping out the relay directly to see if that engaged the starter??




df

I really liked the idea of jumpering the starter solenoid. I did and the results were negative. The engine did not crank with the ignition key in any position. This was done while the voltage was over 12.5 volts on the ignition starter control circuit.

I haven't tried measuring the voltage at the starter solenoid yet. I have to get familiar with that bit of topography.

Is it possible that a clutch pedal interlock is a factor here?

possible, but iirc that's one of those thigns where bmw (apparently) didn't design it in that manner to be a safety switch. mine, as well as many others with manuals, will start without the clutch pedal being depressed....

as for ckecking voltage with a dvom, when checking a power circuit like a starter, just use a test light. if it lights you have power, it should work. plus it's a little bit easier to use in a tight spot like that than trying to wiggle in leads of the dvom.

however, feel free to jump the clutch switch.





df