How to remove/install m42 crank position sensor

[monty23psk]

So after 29 years, my original BMW crank sensor decided to go belly up. I wanted to share this for anyone searching because I couldn't find any info online. I recently developed a hard start issue about 2 weeks ago. Once in a while, the car would die just pulling out of driveway and what had me really look into it, was last weekend, driving over wet road, and going over a large puddle on the highway, the engine would loose power and buckle. Read about this scenario and stating CPS could be it. I did the stomp test and used my foxwell computer when I got home and stated camshaft sensor. I was going to plan on test both sensor and decided to move car out of garage to get more room, and boom, car does not start. Tested cam, came back at ~1300 ohms, so that is good, and crank, a whopping 212000 ohms. A little over the ~560 ohm reading.

Got me Bosch unit from FCP Euro (lifetime guarantee) for under $100 as BMW part is over $230 and only 2 yr warranty. I considered this wear and tear item so can see it being replaced and lifetime warranty surely helps.

Now to the removal and installation. The AC compressor bracket needs to be removed or loosen to get the wiring out. Yes, you can cut the old one but there is no way to install the new one, and follow the factory path using the plastic looms without removing the bracket. You will have to remove the 4 bolts, 13mm, holding compressor to bracket and then go over the  bracket. I remove the 2 front bolts and removed 3 for the bracket. I loose the 4th enough to swing the bracket out enough to slide the wiring in. I used this method to also remove it. Luckily the AC can be supported with car jack to prevent any tubing/wiring issues.

Everything reinstalled in the opposite fashion. Now car has no issue and revs smoothly. Hope this helps someone in the future. You can probably get the wiring ran in a different way but you can run the risk of damaging the wiring or it not be long enough to reach connector under the intake.

[DesktopDave]

+1, great write-up. Dumb choice on BMWs part. The A/C bracket absolutely needs to come out, there's no other way to pull the E30 crank sensor.

[bmwman91]

Ha, well I guess this is one upside to the fact that I removed the AC 15 years ago and never out it back!

[monty23psk]

Ha, well I guess this is one upside to the fact that I removed the AC 15 years ago and never out it back!

Lucky but sure enjoy the cold AC here in humid and sunny Miami, FL. AC is a must here or you only drive 4-5 months out of the year. Now the heater, that is useless around these parts, lol.