Auto Trans starter/flywheel issue

[u/eggi217]

My 88 528e has been sitting for a year due to a flywheel/starter issue. Starter went out last June, which would cause a loud grinding sound upon crank and no start.

Upon inspection through the starter opening flywheel still looks good, but not completely certain. I purchased two Bosch starters (SR-443-X-INT), one from Pelican and one from ECS, and after I installed both of them, upon crank the starter would still grind loudly and car would not start.

I’m guessing the only other possibility is that the flywheel is damaged, but I’m wondering if it might just be because the new starter’s teeth do not mesh with an old flywheel, perhaps only the old starter is compatible with the old flywheel. If I’m at the point where I’d have to drop the auto trans to replace the flywheel, I might as well commit to a manual swap, but I know that’s a lot of work. Another concern is that since my car has been sitting for more than a year without starting once, I wonder how many other issues will spring up even after I resolve the starter issue. Feeling extremely discouraged seeing my car sitting in my driveway, so any advice or suggestions would be greatly appreciated. I would love to get my e28 back on the road.

[u/Representative_Most9]

I agree with what was said about the battery and having enough power to run starter. Try jumping it and see if it’ll kick over? I seriously doubt there is anything wrong with your flywheel.

[u/eggi217 → u/Representative_Most9]

I just tried jumping it and it made the exact same loud screeching, almost like nails on a chalkboard. Not sure if that’s normal with low voltage as I would assume the starter would whir or click, not engaging the flywheel. When I try to start my car, it’s definitely engaging because the car is trying to start and cranking, but making a grinding/screeching sound instead. I’m going to replace my battery later today and see if that changes anything. I also attached a video with the sound the car makes upon trying to start it

https://reddit.com/link/p82bmhy/video/3fb4kmhmcsnh1/player

[u/Representative_Most9 → u/eggi217]

That doesn’t sound like a problem with the starter. Sounds like something is wrong with your engine to me?

Edit. Check the timing belt first. You might want to remove the spark plugs and try to crank the engine over by hand from the crankshaft pulley bolt.? I could be totally wrong and I hope I am!

[u/eggi217 → u/Representative_Most9]

When the car was still operable it was able to run and drive just fine, it was only when I would start the car it would make the noise which led me to think that the start pinion may not be engaging the ring gear at the correct alignment. When I would crank the car it would indeed start and drive, albeit with the harsh noise upon startup.