Inductive cam sensor ?

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jeffmarsh750
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Inductive cam sensor ?

Post by jeffmarsh750 »

Anyone ever try or have any ideas for an inductive cam sensor ? MSD has one but the output is fiber optic. Was thinking of putting one on the last plug wire in firing order. These older motorcycle engines are a pain to install a cam sensor on.
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grom_e30
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Re: Inductive cam sensor ?

Post by grom_e30 »

I had thought about this before as my car had a sensor like this on the no6 plug lead and the idea was that the cam pulse would change with ignition advance
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racingmini_mtl
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Re: Inductive cam sensor ?

Post by racingmini_mtl »

Unless you're certain that the sensor will not be triggered by the wasted spark, it will not work. What you basically have is that you're using the output you want to control as the input which tells you when to activate the output. As you can see this is a rather circular set of events.

But if the wasted spark events are never picked up by the sensor, it would work since the engine is started in wasted spark and you would then have a valid reference point.

As for the changing position with the change of ignition advance, if you position the missing tooth on the crank sensor such that there is never a chance that the cam pulse comes close to the missing tooth, or worse goes across it, then you have a valid reference point. You only need the cam pulse to happen between 2 successive missing tooth events for it to work. Of course, that assumes you're using a dual wheel with missing tooth setup; other setups won't be as forgiving.

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billr
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Re: Inductive cam sensor ?

Post by billr »

It can work, as long as the plug wire is "dedicated" to that one cylinder's firing, just as Jean was saying. I did this many years ago before crank/cam wheels were common. As I recall, capacitive coupling was more practical than inductive, just a bit of metal foil around the plug wire instead of having to build/buy a bulky inductive pickup. Also, Saturn S-series create a "cam signal", somehow, within the wasted-spark ICM.
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