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Hit pothole-car died


My '87 BMW 325e just died after hitting a pretty big bump. Engine turns over but won’t crank. Where do I start? Right now I just want to get it home. Any ideas or past experiences?

Since “turning over” and “cranking” mean the same thing, I am assuming that you are telling us that the starter turns/cranks the engine, but that the engine does not start and run on its own.

If the problems began right after the car hit a big pothole, I would suggest that you check the ignition system for a disconnected wire. If a wire was poorly connected already, hitting a large pothole could have dislodged it.

You may have tripped what’s known as the collision or inertia switch. It’s designed to sense a collision and shut off power to the fuel pump. This stops the fuel from leaking after an accident in case fuel lines were damaged. The good news is you just have to press a button on the switch to reset it. The bad news is I don’t know where it is on this car. Check your manual, the dealer, or maybe someone here knows.

Yes, the inertia switch is another good possibility as the source of the problem.

Yes, the car “turns over” but won’t start.
Inertia switch?
I can hear the fuel pump spinning when the ignition is turned on.
doesn’t this rule out this possibility?
Thanx for the replies. Any ideas are helpful.

VDC - those year Bimmers don’t have an inertia switch (surprisingly), later years do.

Immediate check points for that year BMW:

Fuse 1.
Motronic main relay - may have been dislodged. This should click on with the ignition.
Check the TDC sensor - if this is the front engine clip mounted sensor it may have been dislodged.
Check the main fuel pump is running during cranking.
Check the ECM plug has not been dislodged - the ‘D’ connector should have a retaining screw but you never know with a car of this age.

If all these check out then there is a more serious system problem.

Okay - If the fuel pump is running then the ECM, master relay and fuse #1 are generally good.

Check your TDC sensor. If it’s front mounted it could be the problem. It’s about the size of an AA battery and is mounted on a clip on the front engine housing.

Thanx for the help.
I don’t have a manual, just bought the car last week.
Does anyone know where I can find engine diagrams online so I can locate all these plugs and sensors?

Try one of the many bimmer forums. I have a 1988 E28 with the same engine as your car so I can answer any specific questions. If you just got the car you really want to get hold of a Bentley workshop manual - worth its weight in gold (or perhaps not at today’s prices).

The front TDC sensor I mentioned earlier is on a spring clip at the front of the engine, the clip can rot over time a good jar could shake the sensor free or allow it to contact the front pulley (that’ll kill it).

One other thing I’ll mention - unlike the big 6 engines the 2.7L engine has a timing belt. If you have no evidence of its last changeout you should think about getting a new belt, water pump and tensioner assembly. While you’re checking stuff you might want to pull the dizzy cap off and verify the rotor is turning.

Wiggled all that stuff around and she started right up! Running a bit rough but running. Thanx again for all the advice.

Great stuff !

I’d persevere though and determine why it’s running rough if it wasn’t doing that before ~ otherwise she might just quit on you again.