Starter motor/circuit question on E34 520i manual

[ktteoh]

folks, my e34 520i manual is probably the entry level in the e34 series - a no frills model, no alarm, no EWS/auto starter interlock etc. is a 2 litre m50 engine.

here's the symptom: when i turn the key, dashboard light dims slightly - but no other sound observed - starter motor doesn't crank at all.

oh yeah - sometimes if i give it a good stiff shock via a long screwdriver and hammer, the starter cranks up the engine ok - however chances of this "trick" working is less and less.

battery is good enough to light up all the headlights etc - so i'm ruling out weak battery.

when i used multimeter to check, it seem like the ignition key circuit directly activates a relay/solenoid mechanism on the starter motor itself - at least that's how it looks to be wired.

so questions:
1. what part of the starter motor is at fault?
2. how easy to remove the starter motor without removing the intake manifold?

[ktteoh]

shogun, thanks for the pointer. however after reading it, i don't think it's the same with what i have. my starter is not turning/making any sound while his starter is at least turning.

i'm looking for suggestions of what could go wrong from my symptoms and whether replacing one is an easy DIY task.

Starter motor R&R
just a good timing
http://www.bimmerboard.com/forums/posts/484290

[shogun]

Starter motor R&R
just a good timing
http://www.bimmerboard.com/forums/posts/484290

[shogun]

you have to disassmeble it anyway and then you will see, this motor was also not engaging
http://www.bimmerboard.com/forums/posts/480821/

If it does not move at all, maybe the solenoid is stuck
http://www.lrfaq.org/Series/FAQ.S.dieselstarter.html

quote
The most common failure is the deathly click, where the starter solenoid clicks but the motor doesn't turn. This can be due to 2 common fault scenarios - 1. the solenoid isn't being drawn back enough to close the high current switch and send power to the motor (usually due to a wet or dirty switch, low power due to bad earthing, or a crudded sticking solenoid piston) or 2. the motor is stuck with the bendix gear engaged in the flywheel, and has not the momentum to turn the flywheel (usually due to dried grease on the bendix/armature spindle or bad earthing.) How the bendix gear gets stuck defies my imagination, although I have seen this on many lighter-duty starters.
unquote

[Morgenster]

folks, my e34 520i manual is probably the entry level in the e34 series - a no frills model, no alarm, no EWS/auto starter interlock etc. is a 2 litre m50 engine.

Not really. The 518i was entry-level back then, but yeah, you could consider ours the very basic models.

[Dave M]

folks, my e34 520i manual is probably the entry level in the e34 series - a no frills model, no alarm, no EWS/auto starter interlock etc. is a 2 litre m50 engine.

here's the symptom: when i turn the key, dashboard light dims slightly - but no other sound observed - starter motor doesn't crank at all.

oh yeah - sometimes if i give it a good stiff shock via a long screwdriver and hammer, the starter cranks up the engine ok - however chances of this "trick" working is less and less.

battery is good enough to light up all the headlights etc - so i'm ruling out weak battery.

when i used multimeter to check, it seem like the ignition key circuit directly activates a relay/solenoid mechanism on the starter motor itself - at least that's how it looks to be wired.

so questions:
1. what part of the starter motor is at fault?
2. how easy to remove the starter motor without removing the intake manifold?

1) If you're able to 'jump' the solenoid, then quite likely your solenoid is or will soon be toast. Have you checked to see if you have 12v at the smaller wire to the starter solenoid? If you have power here with the key in the start position, then your ignition system is working up to the solenoid. If not, you need to check the ignition switch and neutral start switch. Do we have a neural start switch on the autos? I'm not sure, you'll have to check. This is the only other item I know of that can also fail and prevent power from getting to the 'small' terminal on he solenoid. Once you find these items, it will be easy (relatively) to find the culprit.

2) I've been told its possible to remove the starter without removing the intake, but I would be hard pressed to do it myself. The job is made a breeze be first removing the intake. If its you first time removing the intake, it will take a while (fuel rail clips, little bots under the throttle body, many hoses etc.), but definitely worth it. As recently discussed here, with the intake removed, you can also inpect/replace the multitude of bits that hide below (coolant hoses, sensor wires, ICV, intake gaskets etc.)

Good luck,

DAve M