BMW 2Series Not Starting – Crankshaft Problem
This BMW 218i was brought into GP Motor Works because the owner could not start the car at all.
We started our work procedure by conducting a diagnostic test. This highlighted an issue with the crankshaft. We attached our scope to the crankshaft sensor to pick up the pattern when the crankshaft was moving. The incorrect pattern showed us there was too much end-float (end play) on the crankshaft. There is an increment wheel built into the rear main oil seal which the crankshaft sensor picks up in order to send a signal to the ECU (basically tells the the ECU what position the engine is in).
The rear main oil seal is situated on the crankshaft. Now if there is excessive end-float when the crankshaft moves in the block, the sensor can’t pick up the signal. This essentially means there is no pulse initiated to the coil to ignite the spark plugs.
We replaced the crankshaft bearing and re-assembled the motor. The vehicle was tested to ensure the engine was operational.
Please don’t hesitate to get in touch with us if your BMW is not running smoothly.
The moral of this story is “early diagnosis of abnormal engine behaviour can end up saving you a lot of hard-earned money”.