BMW E30 no spark - ignition troubleshooting
E30 will not start - how do I check whether there is a spark?
Remove a spark plug, hold the plug lead attached to it and rest the plug body against metal. While someone cranks the engine, the spark is visible. At the same time you can smell the plugs to tell whether fuel has arrived.
What usually causes a missing spark on an E30?
Typical causes are a burnt ignition control box, a fault in the coil or the distributor sensor, and a damp distributor cap. The coil's positive wire must have power both with the ignition key on and while cranking.
Can the crankshaft sensor prevent starting?
Yes. Without the crankshaft signal, the control unit gives no spark and no fuel, so the engine does not start or runs very poorly. The sensor should be cleaned and measured. Crossed sensor wires can also prevent a spark.
The car does not run properly even though parts have been replaced - what else should I check?
Remove the distributor cap and rotor and dry them. Even one small drop of water can disturb the ignition. Also check that the plugs have not got wet; cleaning the plugs and charging the battery has fixed starting faults.