I've been getting code 0336, crankshaft position sensor, lately so I changed the sensor tonight. Still the same problem. Under heavy acceleration the tach bounces around and the comes on. When I'm towing a heavy load the tach will stay at zero long enough that the engine defuels some. To me it seems to be related to the extra vibration caused by the increased power. Any ideas what I should look for next?

Well its fixable... That's all that matters...

It stops as soon as I let off on the throttle.

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Where can I find a wiring diagram for this? I looked in the downloads but couldn't find what I needed.

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Ok I tested the voltage at the sensor. 4.73 volts when grounding through the connector but 4.97 volts when ground the volt meter right to the ground on the battery. Could I be getting a poor ground to/through the ECM? If so how and where does it get its ground?

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Is there nobody reading on here today? I could sure use some input if someone has some.

My truck has been doing this same thing for the pass couple years. Mine will do it with my box and without and is off and on issue. Took it to cummins NW because dealership where i live well to be nice is retarded. I know more about the cummins then there tech does. Long story short my truck is defueling under heavy load aka foot on the floor. Computer is reading no more boost so it cuts the fuel. I had to get a boost fuller and little elbow. That what solved my issue.