Intermittent Cutting Out London Mechanic Needed

[Mitchen]

Hi guys

Got an issue with my E30, when the car warms up, it cuts out. Has anyone else had this issue before? Or better still are there any E30 experts around the South West London area who can have a look? Any help would be appreciated!

Cheers

[Brianmoooore]

Yes, many have had this fault before, but since you haven't told us what model, we can't help further at the moment.

[Mitchen]

Lol sorry.. It's a BMW E30 320i SE Auto. Engine starts again once cold

[Brianmoooore]

Right! Next question is " what does the rev.counter do when it starts to cut out?" Drop like a stone, or just track the falling engine revs?
This will determine whether it's an electrical or fuel related fault.

[Mitchen]

The rev counter just drops flat.

[Brianmoooore]

Chances are that the crank position sensor is starting to fail. This is essentially a coil of very fine copper wire wrapped around a magnet, and eventually the copper wire breaks. The ends touch when the sensor is cold, and it works as it should, but as it warms up with heat from the engine and radiator, expansion opens the break and the car cuts.
Other, more rare, possibilities are the DME relay and even more rarely, the engine ECU itself.
The DME relay can be checked (in the absence of a replacement), by pulling it out, identifying pins 30 and both 87 of its socket, and linking all three together with short pieces of wire while you drive.
DME is the five pin one, usually white, under the cover on the inner wing next to the air filter assembly.

[Mitchen]

Ok appreciate the help. I'll give it a look tomorrow. Could turn out rather pricey if I can't fathom it. Fingers crossed!