If I turn the key quickly when I start my car there is a very loud, high pitched screeching, grinding noise that ensues and the car does not start. If I then turn the key slowly, it starts and runs fine. It happens alot when the engine is cold if I am not careful/lucky in how I turn the key. What is the problem? thanks!
Obvious problem. The ring gear has missing teeth and has to be changed, with the transmission removed.
I cannot connect the fast or slow turn of the key to your problem, anyone care to take a stab at it? If the “ring gear” is missing teeth it should not matter how fast you turned the key.
What year 535 and how many miles and auto or manual trans.
“I cannot connect the fast or slow turn of the key to your problem” Just put that one up to luck.
In addition to what the others said (ring gear), you may have a weak starter solenoid that caused the poor starter engagement to begin with. Now it’s ground away some of the teeth, causing the problem. But please let us know year and miles.
The “slow key turn” is a major parameter of the OP’s post, are you implying the OP is imagining the connection? I am.
I agree with texases, that it is a weak starter solenoid. When turning the key slowly, the solenoid has enough time to engage the starter gear with the flywheel before the starter motor kicks in. Turning the key fast causes the starter motor to engage before the gears have meshed, causing the horrible noise. Better replace the starter ASAP. This condition is slowly but surely destroying the teeth on the flywheel gear.
The key thing is a function of “luck” and “cold”. But at the starter - not the key. Go to shop. Mechanic will find the problem quickly and explain what’s going on. You will most likely need a new starter. Usually the gear on the starter is worn down. He’s the guy that dances with the ring gear. On cars with very high mileage, it can be the ring gear that’s worn out. That will be bad news and expensive. But again, you’re probably due for a new starter - that’s routine and not that expensive. But take care of this now. If you keep going on luck, you risk damage to the ring gear.
So, does this BMW have separate ignition switch contacts for the solenoid and for the starter? That would seem very strange.