2002 E53 X5 Starter issues
 

OK-think I know the answer to this one but I've saved so much time and money by using this forum-I gotta ask: The starter doesn't catch every time, not the clicking associated with an electrical issue, sometimes starts right up-others may take 3-4 repetitions off turn off/turn key. I can here something spinning ,am I missing teeth here, bad solenoid? New starter time? I understand it's a PIA but if I can do door handles/carriers I'm up to it I think. Thanks in advance!

Starter is spinning the bendix that engage the starter to the flywheel is not pushing the gear forward. The solenoid is good or else the starter wouldn't be spinning. Just replace the starter.

https://www.youtube.com/watch?v=RhdSq4WOaDM

I can't figure out from OP's description what the actual problem is, but ...

interesting video, but that design is not what I found in the starter on my 2001 3.0i when I took it apart (nothing wrong, mostly for fun, and to tune it up and replace brushes when I had easy access to it). My Bosch starter looks and works more like this:

https://www.youtube.com/watch?v=Sf6LqYBLljs

which may help in understanding how it is supposed to work, and also what might be wrong.

To be clear, the main difference between the two is that on the Bosch starter, the solenoid - in addition to of course closing the electrical contacts, acting as a relay - actuates a yoke that pushes the gear toward the flywheel. Very different vs. the interesting use of rotational inertia and left handed threads on the shaft by that other one.

OP stated that he can hear (not here) something spinning when he turn the key so I'm assuming it's the starter and not the fuel pump. If the starter i spinning but the engine is not cranking over then it's the Bendix. Whether it's an inertia bendix or one that is actuated with the solenoid it the bendix that is not allowing the starter to crank over the engine. Sometime a solenoid actuated bendix can also go bad.

I still don't know exactly what he means, so would rather not guess.

I just wanted to provide an accurate schematic / video of how my Bosch starter (and likely how all E53 starters) works, since it's different than the one in the other video.

Really interesting how the non-Bosch one relies on the rotational inertia and threads for actuation. The guy said it came out of a Honda, not sure who made it. Very different from how the Bosch works.

Having played with British import in the 70's, 80's and 90's and owned and raced a Formula Ford I can tell you that they all use inertia starters to cranks the engines over.

Could be a worn out ring gear, and that would match your symptoms. And that's a bad time. Remove your starter, spin the engine with a bar on the crank pulley and inspect the flywheel teeth. If they're good, replace the starter.

Thanks for the replys-sorry I can't describe it better-I'm gonna replace the starter. Thanks!

I don't know what kind of car the OP has. But at least on my 2001 3.0i, inspecting the ring gear through the inspection port on the AT is about 100x easier than removing the starter. Even easier if your inspection port cover is missing, as mine was.

Also note my rust-preventive oil layer in the photo. :rofl:

If it were my car, with a general problem with the starter not spinning, I would do more electrical troubleshooting first - e.g., bypassing things that could be causing the failure without it actually being the starter that is at fault.

When I "rebuilt" (not much really needed) my starter when I had easy access to it, I really did not do much. Cleaned out some debris from brushes, renewed grease, replaced brushes (although existing ones had 70% left at about 186k miles), and cleaned up some electrical contact surfaces. No signs at all of anything deteriorating.

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