DIY: R&R crankshaft position sensor
 

I first reviewed my BMW TIS which simply said to remove upper intake manifold and disconnect/remove sensor. No way could I get my arm around the lower intake manifold, down past the dipstick to reach the "pulse sensor", in front of the transmission mounting flange.

I decided to remove the lower intake manifold from the engine, leaving most of the wiring harness connected...or just enough to drop the lower intake manifold to reach around it to access the ALLEN HEAD fillister bolt holding the crankshaft pos. sensor in place.

http://images2e.snapfish.com/2323232...3A882344nu0mrj

In the above photo, I fit my arm around the lowered intake and followed the dipstick down to where it enters the engine base, sensor is to the LEFT of the dipstick, facing rear.

http://images2e.snapfish.com/2323232...%3B84253ot1lsi

Crankshaft position sensor, located between starter and dipstick opening in engine. Photos shows the side of the starter on the left.

http://images2e.snapfish.com/2323232...36%3A344nu0mrj

The hex head bolt takes a 5MM allen wrench to unscrew. I had to place the long end of the allen wrench in the bolt to get enough clearance to put a stubby box end wrench on the short end of the allen wrench to break the nut loose. It not very tight (thankfully) and had blue Loctite on the threads..assuming from BMW as it was the original BMW crankshaft position sensor.

Disconnect the crank. position sensor plug from the wiring harness connector "box" located in the center of the lower intake manifold.

Pull the sensor out of its mounting hole. There is an o-ring on the sensor, I did not order one... "assuming" it was included with the replacement pulse sensor (NOT).

http://images2e.snapfish.com/2323232...87%3B344nu0mrj
Old OEM sensor on left, replacement VEMO sensor on right, O-ring lower center .
Re-install sensor with o-ring, install allen head bolt (with blue Loctite) and tighten (no torque value ...snug it up to re-compress o-ring).

Thread the wire from sensor up into center of lower intake manifold and reconnect crank. sensor plug to wiring harness wiring "block".
Reinstall lower intake manifold (M7 nuts take ~15NM IIRC) , fuel injector rail, upper intake manifold with wiring, vacuum hoses, accelerator and cruise control cables. (REFER to Cooling System Rebuild for details :wink: )

FWIW: I did not have a sensor failure, just did the replacement for "peace of mind". With >120K miles on the ti and a long trip down to Alabama this Winter, I would rather not have any problems.

This is also a good time to replace the cabin air filters as it makes the upper intake manifold removal easier when you move the rear wiring harness and cabin air filter housing which juts into the center engine bay.

Nice write up.

It can be done without removal of the intake. It's painful, but it can be done. I also made my own allen socket with a old allen key and a 5mm 1/4" socket.

I'm thinking you could access it from below too....IF the car was on a lift. You still have to unplug the connector which would mean removing the upper intake manifold.

I have my parts now, want to help put mine in on Sunday?

I would...but...have Nat.Guard this weekend..SRY
My intake mani. gaskets and O-rings finally shipped today, won't be able to put mine back together until next week. Like you said, thank God for two cars.