Hey I need some help. My 2002 cummins will lose boost sometimes when I let off the accelerator and/or when I am coasting down a hill or into a turn. I have had one person tell me it is the throttle positioning sensor. Has anyone had this trouble before ?
THANKS!!

 

Tell that "one person" to step away from the crack pipe!!! Normal tolose boost when coasting... I bet, if ya watch the tach the rpms go down as well.

 

olegoofynut,

Welcome to the forum. Is this your first diesel truck?

I'm not gonna bash you, as I don't understand the circumstances that you are raising the question. The condition is completely normal. Boost is built by heat and pressure. Both of these come from stepping on the accelerator, which burns fuel, which causes heat and pressure and, in turn, spins the turbine wheel. As soon as you let up on the pedal, boost falls off.

No pushy the pedal, no makey the boost.

A good indication that you actually have a problem will be if you are making excessive black smoke (Uhhhhh, on a stock truck [:-]). This would indicate that you have some kind of air flow issue or a stuck injector.
What I suggest is this.......DON'T EVER LETTHAT ONE FRIENDGO NEAR YOUR TRUCK UNTIL HE[sm=icon_rtfm.gif]

 

Trouble with friends that don't understand diesels all the time. Once your big heavy truck stomps their pride and joy they back off