E30 Not Starting

[olmsteade]

I own an '89 325i. It will run when it wants to. When it does run it may decide to just randomly shut off at any time, in gear, driving down the highway, it doesn't matter. There is always power at the coil. It just doesn't get to the spark plugs. The master relay has been replaced and meters out with in specs. The reference/pulse sensor tests out ok. I have replaced the Motronic EMC and that didn't do anything. One thing I have noticed is that when the car is going to start you can tell because when you turn the key the Check Engine light will come on with everything else. When it's not going to start, no check engine light. The plug wires or distributor have not been touched, but when the car starts it runs and idles fine. Any ideas would be much appriciated. I have been trying to nail this ghost for awhile now, and being stranded is getting old.

[Boston e30]

Pull the distributor and examine the contacts on the cap and rotor. Make sure they arn't caked with burned residue.

[bad man working]

When you say the motronic EMC I take it you mean the motronic control unit (DME ECU) if so:
I think you’re loosing a main feed or earth to the to the DME ECU or the crank sensor signal.
I’m a Brit so I don’t know how the engine management light works on an E30 but it sounds like the DME ECU isn’t turn on. Volt drop test the main feeds and earth at the DME ECU. I can give you pin numbers etc but BMW use DIN standard wiring so the Feeds will be heavy wires main red ands the earths will mainly brown. To test the crank sensor you should get a 2-5voltage AC approx from the sensor at cranking speed, with out that AC voltage the DME ECU won’t turn on

[olmsteade]

Than you very much. I wasn't aware of this but the DME relay has it's own feed coming right off the battery and it was only getting about 2 volts do to a frayed wire and the connector to the terminal. Problem solved.