Most old injection systems dont have cam sensors i.e. 3.5 and 3.9 Rover V8s, early, L-jetronic, most SPi setups....
As for the wasted spark, here is some more info for the melting pot.
You have two spark plugs firing at the same time but, they will not have an equal voltage across them......but why...
Well again its simple, the voltage required to create a spark across a given gap (i.e. a spark plug) is related to a number of factors and one of the important ones is pressure....
So, if you were to measure the voltage across the sapr plug you would find about 40KV across the one on the compression stroke and around 4KV across the one on the exhaust stroke.......and as some of you may ahev noticed this i a close correlation to the compression ratio and is indeed due to the fact that teh cylidner pressure at the top of the compression stroke is 10 times that of teh cylinder pressure on the exhaust stroke.
This works in your favour as you now only need a coil that is insulated slightly better thn a standard one rather than what some expect would need to be twice that of a standard one.
As for the type of sensor used for cam and crank.....it does vary from system to system with reluctance being a common one but, hall sensors not being un-heard of.
The cam sensor on the 4 pot is actualy unusual as it has a sine wave of some few hundred KHz applied to it!
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Topic: Camshaft and Crankshaft Sensors (Read 2557 times)