My car wont crank over when i go to turn the key, but all electrical stuff works fine.

1994 BMW 740
240,000 MILES
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94BMW740I
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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
Aug 2, 2012 at 7:03 AM
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ASEMASTER6371
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basics first, compression test, fuel pressure and spark test. one of these will be missing. then we can proceed.

Roy
Aug 2, 2012 at 10:11 AM
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MIKEDEROUIN88
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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.
Aug 2, 2012 at 10:49 AM
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ASEMASTER6371
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sounds like the starter is turning but not starting

Roy
Aug 2, 2012 at 12:49 PM
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94BMW740I
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I believe that's what its doing Roy, could it be something simple like a break in a wire, or corrosion?
Aug 2, 2012 at 2:51 PM
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94BMW740I
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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?
Aug 2, 2012 at 2:53 PM
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ASEMASTER6371
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possibly, clean the battery cables and have the battery checked for load. if it is ok, you may have a failed starter motor.

Roy
Aug 2, 2012 at 4:47 PM