2002 GMC dmax Allison 33k no mods

I have a question to those who know:

What are the symptoms of a failing or failed crank position sensor?

My truck when I stomp on it bogs down and even slows down considerably when I approach 2800-3100 rpm at 55-70mph or from a takeoff position.

Any assistance is appreciated.

Dale

when was the last time you changed your fuel filter?

Admittedly I am a non-diesel-know-it-all, but why do you need a crank position sensor in a diesel engine? I thought a crank sensor was for spark timing :confused:
JP

Admittedly I am a non-diesel-know-it-all, but why do you need a crank position sensor in a diesel engine? I thought a crank sensor was for spark timing :confused:
JP
Without some method for getting engine timing, how would the computer know when to electronically inject the fuel? I am also guessing, but they probably are getting engine RPM off the crank signal, too.

If you think your crank sensor is becoming intermittent, it will probably set SES light.

It gets more complicated than that. I believe the computer uses the signal not only for knowing the crank position, but instantaneous velocity of the crank. Every time a piston comes up on compression, the speed of the crank slows down. Every power stroke, it speeds up. The computer measures this change in speed, and compares results from cylinder to cylinder. If one cylinder doesn't slow down and speed up the crank as much as the others, the computer adjusts the balance rate on the injector for more fuel, thinking that that cylinder isn't contributing enough on its power cycle.