Starter spins w/out engaging or key in ignition (Electrical Buffs where you at)

[6SPD]

Greetings Interwebs.

I've had a recent and very odd electrical issue going on.

When I start the car (usually on the start after sitting for a night or most of a day) the car starts up fine and runs, except the starter will disengage like it's supposed to but continue to spin (sounds like a high spinning electrical whine coming from the rear of the block).

I'll remove the key from the ignition entirely and the starter will continue to spin and I can also turn on the fans inside the cabin without the key being used.

I then will pull the battery lead and reset it, starting the car normally without an issue afterwards...



Anyone got any ideas?

I've heard something about the unloader relay being a possible issue...

[StereoInstaller1]

You may have the unloader and the stater wires reversed, or the starter itself may have failed internally.

Have you done any major work that may have caused the two to be reversed?

[6SPD]

You may have the unloader and the stater wires reversed, or the starter itself may have failed internally.

Have you done any major work that may have caused the two to be reversed?

About 2000 miles ago a stroke m20 was swapped in (E to I swap).

The starter is a rebuilt Bosche unit.

There has been zero issue with anything electrical until this past weekend when this issue originated.

[StereoInstaller1]

About 2000 miles ago a stroke m20 was swapped in (E to I swap).

The starter is a rebuilt Bosche unit.

There has been zero issue with anything electrical until this past weekend when this issue originated.

OK, cool. My first thought was the nuts that hold the terminals may have come loose, so you may want to check them first.

[Gordo0208]

Get a multimeter, put your negative on a good ground with an alligator clip, pull the signal wire and have someone crank the car while you measure the signal voltage. Since the car does start you should see 12v, what you want to see is if the starter is still getting a signal after you've stopped sending the signal. If the signal stays at a constant 12v after you let the key go then you might have a short to power (should've blown a fuse). If the signal disappears as it should, bad starter.

[jlevie]

While the starter continuing to turn could be sticking solenoid, the fact that this is a new problem says that it isn't mis-wiring of the starter. Since this was an E car, it doesn't use an unloader switch to disable the HVAC, windows, and mirrors when the starter is running. The fact that those functions work with the key off or out says that there is a major electrical problem somewhere and the fact that disconnecting the battery causes normal operation suggests that a relay is latching and powering up things that should be only controlled by the ignition switch.

[6SPD]

While the starter continuing to turn could be sticking solenoid, the fact that this is a new problem says that it isn't mis-wiring of the starter. Since this was an E car, it doesn't use an unloader switch to disable the HVAC, windows, and mirrors when the starter is running. The fact that those functions work with the key off or out says that there is a major electrical problem somewhere and the fact that disconnecting the battery causes normal operation suggests that a relay is latching and powering up things that should be only controlled by the ignition switch.

Great insight. Any idea which relay it could be? Thanks!

[StereoInstaller1]

While the starter continuing to turn could be sticking solenoid, the fact that this is a new problem says that it isn't mis-wiring of the starter. Since this was an E car, it doesn't use an unloader switch to disable the HVAC, windows, and mirrors when the starter is running. The fact that those functions work with the key off or out says that there is a major electrical problem somewhere and the fact that disconnecting the battery causes normal operation suggests that a relay is latching and powering up things that should be only controlled by the ignition switch.

ETAs had unloader relays just exactly the same as a B25 car. This ETM is for an 85:

http://www.wedophones.com/Manuals/BMW/1985%20BMW%20318i%20-%20325e%20%20Electrical%20Troubleshooting%20Manual.pdf

Page 105 clearly shows K5 and K7.

[jlevie]

Great insight. Any idea which relay it could be? Thanks!

I can't think of any stock relay that could do this if the car's wiring is in the stock configuration.

[jlevie]

ETAs had unloader relays just exactly the same as a B25 car. This ETM is for an 85:

As does a 325i/is produced from 9/86-8/87. But the wire that goes to the unloader switch on later production cars is tied to ground so that the relays close with ACC circuit hot.