The pulse sensor on the #6 cylinder is used to sequence the injectors on the motor, it tells the DME which bank of injectors to fire as the M30 is a batch fire injection system (fires 3 injectors at a time).

It should take the DME no more than 2 full revolutions to find out where the motor is, the first to find TDC on the crank, at which point it will start sending spark, the second to find out which cycle it is in via the pulse sensor on the #6 piston. Now the motor may start sooner than that as the injectors will start firing once TDC is found on the crank. I've had the M30 in my '90 535i start in less than 1 revolution (very rare) where TDC on the crank was very close to the CPS. When it does that, it starts on the 3rd compression stroke (I hear the starter push over 2 compression strokes and fire on the third).

'90 535i - 9/89 production

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  • Re: m30 ( and Other Engines ) - how many cranks does it take to start yer car? - Paparon 2008-01-29 02:48:05 (120 views)
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