85 735i - No spark on plugs

The car was running then died while idling on the freeway. It started again and then died while idling again a couple minutes later.

Upon examination there was no ignition spark. We replaced the cap, the coil, the rotor, a small relay that turns on and off the ECM, pulled the ECM and put it in another BMW of the same model and verified it was working but the car still did not have a spark.

We then unplugged and cleaned every connector we could find in the engine compartment. After this the car started. It was idling for 20 minutes and then died but restarted again. We turned it off and it would not restart. We unplugged and replugged in all the connectors again and it still would not start.

*A previous electrical problem was that the starter would not activate through the ignition switch so we installed a starter button directly to starter solenoid.

Can anyone give advice on what to try next? Thanks!

could it be the crankshaft sensor

it was the crank shaft sensor
problem fixed

just saw the post and was going to say crank sensor, but it looks like you have got it sorted.


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Where is the crankshaft position sensor on the M30?

Crankshaft sensor