540i Won't Start

[MBXB]

I get in my car yesterday and fire it up...cranks hard but won't catch. Battery reads 12.5 V; Half a tank of 93.

I grab the Peake reader and it reads a 1A: Control Unit Supply

Control Unit = DME?

I'm off to check fuses and relay contacts.

Thanks

Ramon

[Jr ///M5]

Check fuse #23 it's a 15amp blue fuse in the box on the driver's side under the hood. It's the fuse to the fuel pump. Mine did the same thing day before yesterday. Replaced the fuse, all is good so far. I do hope it's not the pump on it's way out. It was however, the original fuse, so after 14 years maybe it just gave up.

It's worth a quick check anyway. Hope it's something simple like that.

JR

[Tiger]

If not the fuse, then CPS.

[MBXB]

Pulled all the fuses and relays, checked with a good continuity tester, NO bad ones, cleaned and sprayed them with contact cleaner.

Checking the CPS next.

[632 Regal]

after CPS next stop is fuel pressure

[MBXB]

Going to borrow up a fuel pressure gauge tonight.
I can access the fuel line on the return (driver's) side easily. Will that show a good reading of the pressure?

[MBXB]

Anyone know the manufacturer of the OEM BMW Crank Position Sensor?

[shogun]

do NOT buy after market in this case, read much about probs especially with the M60 engine, such as FACET or other after market brands
http://www.7er.com/forum/4/engine-st...lem-98274.html

[MBXB]

Thanks for the heads up, Erich.
I found another reference with pics too:
http://www.bimmerboard.com/forums/posts/477424

[MBXB]

CPS replaced and all is well.

The only aftermarket I found was from Carquest ($68), as suggested by e34jef on bimmerboard.
It was a Delphi unit. It did not look like the OEM unit, but it was the only thing I could get on short notice other than paying thru the nose at the stealer.

I suspect that the newer sensors use a neo magnet, while the OEM sensors use ferrite or alnico.

For the M60, remove the ductwork from the ICV and throttle body through to the air filter. (3 clamps, 4 air filter clips); then you can reach in and guide the hex wrench with an 18 inch extension to remove the sensor.

Wiring was no problem; No dissection of the wiring harness needed. One lead winds up along the dipstick and plugs in on top of the wiring harness on the passenger side.

The engine started right up. Idle is good; no codes.