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My tach is not working and I understand the system a little. I have found the wires coming from the crank sensor and have tested them but I'm not sure what it is suppose to read? There is a brown, a black, and a white wire.
Can someone tell me on my 99 model 996 what the wires are suppose to read. I assume that one is positive one is grnd or low ref. and the other is
the signal. Just not sure what the voltage is suppose to be on them.
Thanks in advance,
John
The signal (ac) varies with the rpm from 0. Something volt to about 50v. I only tried with a scope so not sure if a dmm can measure that. Most likely it should be able to.
Really needing the voltage on the wires that are not the signal. Just not sure what the positive is
supposed to be? I know the grnd or low reference won't read anything but there should be a certain amount when you read between the positive and low reference/grnd wires.
Thanks!
John
The brown wire is just a shield that connects to the ground (chassis). The white and black wires don't need external power at all. When the engine is at rest, they don't generate any voltage. When the engine is spinning, they produce an ac signal that is proportional to the rpm.
Does your engine run at all? If your engine runs, your crank sensor is fine.
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