ECM sensor question

[Teddennis]

I have a 1994 525i I bought for my son. The car wouldn't start one day after school, but started immediately for me the next day when I checked it. About 2 days later, I drove it, parked, and when I came back out it would not start (I also did not hear the fuel pump charge).

I pulled the fuel pump out & it tests fine. The fuel pump relay appeared to be faulty, as I could jump the connection & power up the pump & power was present on the the relay control (also verified the ECM relay was functioning as well). The new fuel pump relay would not engage. The wiring diagram indicates the fp relay ground comes directly from the ECM.

I researched a few forums and determined there is at least one sensor problem that can tell the ECM not to start the car (the crankshaft position sensor - apparently if it fails, no fuel or ignition). Is this the only sensor that could prevent the ECM from signaling for start? Will the code reader (from Peake Research perhaps) identify a faulty crankshaft position sensor?

I am trying to find the shortest (and least expensive) route to determine if the ECM is defective or an external sensor. Any help would be appreciated.

Second issue: The ignition key cannot be removed from the column. Anyone have any experience with this? Is it a mechanical issue with the switch itself or could something else be locking it?

Thanks!

Ted

[Jeron]

The ignition key cylinder could be the root cause. See if it is functioning. If so then the crank position sensor is the most likely culprit.