1994 BMW 525i (E34) won't crank

[Datamacjoe]

I bought my car used. The previous owner said he had $4k worth of work performed on the car a couple of years before I purchased it. He also said that he had a new timing belt installed. The car ran very good and tight as if brand new. I had a starting issue at first that seemed like the starter motor wasn't fully engaging the fly wheel. Had a new starter install by a good shop which solved the starter motor issue.The radiator blew a hole in the plastic part of the tank which made the car run hot. I had it towed home. In the process of figuring out why it continued to run hot after getting new radiator I discovered the cap was bad. Once I got everything replaced the car stopped cranking. The battery is fully charged but when I turn the key I get absolutely nothing. All dash lights come along with all electrical components seem to be fine with the car in the on position. I am mostly certain that something of an electrical presence is causing the starter not to crank. I have checked fuses in the fuse box on the left side of the engine compartment.

I would like advice as to how to search the cranking process in somewhat of an in-line trouble-shooting method.

[theBMWbeast]

when I turn the key I get absolutely nothing.

Had this exact same problem with my 89’ 525i. I resolved it by removing the neutral safety switch (car is an automatic) disassembling the switch, and cleaning all contacts with rubbing alcohol. Heavy corrosion on those little strips, and afterwards the car starts IMMEDIATELY, every time.

If if you want to troubleshoot this, try banging the car into park a few times, then trying to start it. That used to work for me, so if that cures it definitely take a look at the neutral safety switch. (All of this assuming the car is an automatic, if not then it’s a moot point). (Also I just remembered that the car won’t crank with a bad Crank Position Sensor, but I am speaking from experience with an M62)

Goodluck

[Datamacjoe]

Thanks will try that. And yes, the car is an automatic.

[Datamacjoe]

Have another question idea. Is there a way to by-pass everything, as in "hot wire" start the car so that I can work backwards to the fault?

[theBMWbeast]

Have another question idea. Is there a way to by-pass everything, as in "hot wire" start the car so that I can work backwards to the fault?

You can jump the starter relay, and I think you can toggle on the starter independently via the diagnostic port. I recommend searching for these two things to get a more detailed set of instructions.

[Datamacjoe]

You can jump the starter relay, and I think you can toggle on the starter independently via the diagnostic port. I recommend searching for these two things to get a more detailed set of instructions.

I
I just tried jumping the starter from under the hood. I believe that the connection to make the starter run and engage the flywheel is the bottom screw connector. When trying that, using a metal rod, I can see a small spark indicating that I am making contact. However, I still get no reaction from the starter. Realizing that the larger screw connector is directly connected to the battery I should have a strong charge going to the starter. Since the spark is small, I think something else must be limiting the amount of electricity coming from the battery. I will be looking to do the same from the diagnostic port.

[e34.Dom]

+1 on the neutral safety switch, happened to me about 3 months ago. Do yourself a favor and dont order the non OE replacement. My did dad did that and it doesnt work correctly.

[bimmernub]

May be crank position sensor. I know it cuts the fuel pump off, don t remember but may stop it from cranking too.

[drewusmaximus]

Does your car have the security with the chip in the key? I had a 2001 325i and the car would not start because the security chip in the key was toast. No crank at all. I had to bypass the security in order for the car to start. In my car there was a white box under the steering console. I had to cut the blue and black wires and bind them together and voila! The car started.. It would have cost 140.00 to get a new key with a new chip and it had to be programmed with the ECU. I went the ghetto route and cut the wires.