Testing crank & cam sensors

[Priit Varik <Priit.Varik@xxxxxxx>]

Hello,

My E34 530i with a M60B30 engine has eveloped a nasty intermittent engine
cut-out problem. Also the idle tends to drop low when idling warm. The tach
needle goes down to 500rpm and all lights dim somewhat at idle.
Various mailing lists suggest that the problem may lie within the Motronic
unit or with the bad rpm sensor.
Before trying to replace the expensive ECU, i'd like to test the cheaper
sensors first.
I've found some reference resistance values for both the cam and rpm sensors,
but I'm sure this static test won't reveal all possible problems.
So I intend to check their dynamic response with an oscilloscope.
What I do not know is what should I look for on these oscillograms?
What should the picture look like for a good-condition rpm and cam sensor?
What level should the signal be for ECU to correctly read it?

Any insight is very much appreciated.

Priit

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