I have a 98 F-150 4.6. Reconnected engine after about a year disconnected. Replaced timing set and oil pump. I have no voltage to the crankshaft position sensor. Where could i find a wiring schematic or diagram so that i could trace back to see where i am losing the power. Any help would be appreciated. Thanks, Felixbot.
The crank sensor on your engine is a variable reluctance sensor, therefore it does not have voltage applied to it.
When the steel teeth pass the sensor element, the magnetic field of the sensor is disturbed and the sensor produces an output signal from that changing magnetic field.
Steve
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Think about it: Ignorance can be addressed through education but you can't fix stupid! ...apologies to Ron White
it says in my haynes manual to remove harness from sensor and check for voltage at plug with key on. it cannot produce a signal without some kind of input signal.
With the ignition in RUN, you should see 1.0 - 2.0 VDC at both terminals of the CKP sensor. This is a bias voltage.
If the voltage is not present, either a short-to-ground in the CKP circuit exists, an open in the CKP circuit exists, the PCM is missing an input voltage (does the CEL come on during bulb proveout?), or the PCM has a defect.
Start with checking the CEL lamp, you might be troubleshooting the wrong end of the circuit.
Steve
__________________
Think about it: Ignorance can be addressed through education but you can't fix stupid! ...apologies to Ron White
The cel comes on but goes off after a few seconds. There are no stored trouble codes in the system. When trying to start for the first time, I plugged in the Engine harness but did not tighten the bolt that pulls it together. in my initial frustration, I tightened the bolt while the key was on. Could I have blown the computer? The engine was out for about a year so its possible the terminals in the main connector could be dirty or corroded. I will check that next.
I found the problem. The engine builder did not install the crankshaft sensor tooth wheel when reassembing the engine. I removed the front cover and installed the missing wheel and when reassembled it started right up. Thanks to everyone for their help.
Felixbot
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98 4.6 no voltage to cpk
