Mechanics

MY CAR WONT CRANK OVER WHEN I GO TO TURN THE KEY, BUT ALL ELECTRICAL STUFF WORKS FINE.

1994 BMW 740 • 240,000 miles

When I got in my car today to go to work, I went to turn the key and it would not crank, it spun over just fine and all the lights and radio, etc came on on the dash like normal. There were no new warning lights, and no warning for this at all. I checked the battery and its good, and made sure it was connected good, clean, and tight. I've heard there is a lot of corrosion that goes on with bmw wirings, so I thought maybe that could be it somewhere? I'm lost, and desperately need this car back up and running so I can get back and forth to work! I love this car and this is the first problem I've had with it in 7 months! Please help if you can! Oh, and when you turn the key over the last position to crank it, there is a very faint humming under the hood, and it stops when you let go of the key. Not sure if that's any help.

1994 740I v8
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94bmw740i
August 2, 2012.



Basics first, compression test, fuel pressure and spark test. One of these will be missing. Then we can proceed.

Roy

If I'm understanding you correctly it doesn't turn over at all? Check all ignition fuses and relays, if all check good check for power to the smaller wire on the solenoid with key in on position. If there is power have the starter checked if not check ignition switch.

Tiny
Mikederouin88
Aug 2, 2012.
Sounds like the starter is turning but not starting

Roy

I believe that's what its doing Roy, could it be something simple like a break in a wire, or corrosion?

Tiny
94bmw740i
Aug 2, 2012.
And that's correct, it doesn't turn over at all. When you turn the key to position 1 everything lights up like normal, then when you go to crank it over it doesn't do anything. But if you hold the key in the crank position you can slightly hear a humming from under the hood, when you let the key turn back it stops. Is this the starter trying? Or?

Tiny
94bmw740i
Aug 2, 2012.
Possibly, clean the battery cables and have the battery checked for load. If it is ok, you may have a failed starter motor.

Roy