What the heck is defueling?

[JohnCollins]

And does my stock 04 do it and why? Just trying to understand. I keep seeing this term and have found no explanation of what it is and why it occurs? Thanks

 

[PSchwering]

Defueling is a general term for when the engine governor restricts fuel delivery for engine preservation. IE: If you mash the accelerator to the floor, the engine should rev to a preset RPM, then Defuel. The restriction in fueling keeps the engine from overspeeding & destroying it self.



Does your 04 do it? It depends on how you drive. If you never exceed 3kRPM's, then no, you are not going to notice it.



Defuel is not important to the everyday driver, but to racers & sledpullers, it is very important indeed. P.

 

[B.G. Smith]

"Defuel is not important to the everyday driver, but to racers & sledpullers, it is very important indeed. P. " I would beg to disagree, I think it is probably more important to the everyday driver than the hot rodder. For instance if you are hooked up to a 5th wheel or any load for that matter and have the automatic transmission and you are getting up to road speed in a hurry, I think if the computer didn't defuel when the transmission shifts the Cummins would mangle the drive train in short order. I'm sure the experts will let us know more about de-fueling. bg

 

[sanfordJ]

Is this why the 48RE transmission seems to shift slowly at wide open throttle?

Is my engine being defueled before the shift actually takes place which makes it seem like the transmission is shifting slowly?

 

[DieselFiend]

engine isn't defueling when the RE shifts. You'd know it for sure if it was and it would be annoying as heck. but, defueling is good when you're bombed, whether you'd be a daily driver or a sledpuller.

to really feel the engine defueling, turn all your mods off, hit the freeway onramp and put it to the floor. You'll notice that the engine isn't giving you everything all at once. It's a gradual, steady power. Turn your mods back on and hit the freeway on ramp again. you'll notice that the power isn't so gradual or steady anymore. Defueling is limiting the amount of fuel or the amount of time the injectors stay open. Your boxes up the ante a little bit on your engine.