325i engine stalls at idle then won't start

[tommygoldy]

My new E30 has had a slightly iffy idle since I bought it a week ago. Today it's been particularly annoying.

First up it took a while to start this morning. Nothing, then it went as if nothing was wrong. When I pulled up at my destination as the revs dropped from parking the car it stalled and then failed to start again.

After a while it started as if nothing was wrong. Got me home and did the same thing. Last turn of the key it wouldn't start - see the video below. The MPG meter (and to a lesser extent the temp guage) all move erratically before the car dies :



I'm hoping that above will be some clues to those more knowledgeable than myself - I hope someone can point me in the right direction!

[tommygoldy]

Just pulled a plug. No spark.

[Speedtouch]

Check the crank position sensor is securely positioned, and that the wiring to it is OK.

Also check distributor cap and rotor arm.

[tommygoldy]

Check the crank position sensor is securely positioned, and that the wiring to it is OK.

Also check distributor cap and rotor arm.

There's no fuel either so I'm guessing CPS. I've had a quick look to see if I can work out where it is and I noticed that there's a bunch of sensor wires which are loosely routed around the front of the block where they're able to rub against belts, pulleys etc. This can't be right, surely? I'm now suspecting damage to these wires.

How should they be routed?





Haynes manual's in the post

[Speedtouch]

You're right, they should be secured so that they don't rub against pulleys, etc.

Check them all carefully for any signs of chafing. If your CPS cable is chafed through, that would almost certainly kill it!

[tommygoldy]

OK, I've traced the wire from the CPS back to its connector. I'm a bit confused here because its terminated with a 3-pin connector. Am I going mad?

Either way, when checked with a multimeter no combination of the pins gives a 540 ohm reading - they're all open circuit as far as I can tell.

It's this thing, right? Actually looking at the picture the wire looks damaged where it joins...

[Speedtouch]

Yes, and you're right, it looks damaged, as if it has been forced over at a sharp angle, which may well have torn the thin cables inside. Try a new connecting lead to it.

You could try pushing cable back into the connector, and holding it there while someone cranks the engine over, to see if it will start.

[Billwill]

I believe the one pin may be for the shield and Black, Yellow are the outputs of the sensor but I am not sure what motor you are showing here

[tommygoldy]

From the digging I've done it looks like 3 connectors is standard, although strangely at odds with what I've found on the wiki etc...I wonder if I can get one tomorrow.

GSF are quoting £60 on the phone but have this online for considerably less:

http://www.ebay.co.uk/itm/Crankshaft-Se ... 41699319d4

Ones for later cars also look very similar...I wonder.

http://www.ebay.co.uk/itm/BMW-3-SERIES- ... 3cca9c779e

This listing gives a part number of 1214 1 720 852 (12141720852)

http://cgi.ebay.co.uk/ws/eBayISAPI.dll? ... ink:top:en

[Speedtouch]

You may not need the actual CPS itself, just the connector and lead.

If you're handy with a soldering iron, it may be possible to repair the lead you have.

[tommygoldy]

You may not need the actual CPS itself, just the connector and lead.

If you're handy with a soldering iron, it may be possible to repair the lead you have.

I'll have a look tomorrow. Looks like the lead may be moulded at the sensor end though.

[tommygoldy]

Fixed it! (I hope)

Secondhand CPS fitted and all seems good. Thanks for all your help!

[Speedtouch]

Congratulations, must be a relief.