Locked in High Boost

[Jetmek319]

Folks…

I have come across a perplexing problem with my late 04 model F250. About two weeks ago my truck started running “different.” Shift point were much higher in the RPM band, turbo farts happened continuously (not just after sudden decel, but while gradual decel too) I have an SCT Livewire and took readings before (when the truck was running “normal”) and after when it started misbehaving. The reading were on the same stretch of road under very similar weather conditions (i.e. flat-straight road, no wind, 80 degrees, cruise set, no A/C)

The before numbers were: idle [-2 to -2.2 psi boost], 75 mph, [9-10 psi boost, 190-192 coolant temp.]

The after numbers were: idle [-1.7 to -1.8 psi boost] 75 mph, [21-23 psi boost, 202-204 coolant temp.]

Boost on a normal accel (exit ramp to highway) went from 18-19 psi to 25-26 psi.

It’s like I’m stuck in a high-boost-high-demand condition. If it were a gasser I would say the choke plate was stuck closed. I replaced the EBP sensor 500-700 miles ago, air filter is clean, no trouble codes (other than a P0000). I am in the process of updating my AutoEnginuity so that hasn’t been run yet. Any ideas??? Coked up turbo ??? whacked sensor??

[RRonning1984]

It sounds like you are running a "hotter" tune but if thats not it then I have no idea!?

[psd_va]

Originally Posted by Jetmek319

Folks…

I have come across a perplexing problem with my late 04 model F250. About two weeks ago my truck started running “different.” Shift point were much higher in the RPM band, turbo farts happened continuously (not just after sudden decel, but while gradual decel too) I have an SCT Livewire and took readings before (when the truck was running “normal”) and after when it started misbehaving. The reading were on the same stretch of road under very similar weather conditions (i.e. flat-straight road, no wind, 80 degrees, cruise set, no A/C)

The before numbers were: idle [-2 to -2.2 psi boost], 75 mph, [9-10 psi boost, 190-192 coolant temp.]

The after numbers were: idle [-1.7 to -1.8 psi boost] 75 mph, [21-23 psi boost, 202-204 coolant temp.]

Boost on a normal accel (exit ramp to highway) went from 18-19 psi to 25-26 psi.

It’s like I’m stuck in a high-boost-high-demand condition. If it were a gasser I would say the choke plate was stuck closed. I replaced the EBP sensor 500-700 miles ago, air filter is clean, no trouble codes (other than a P0000). I am in the process of updating my AutoEnginuity so that hasn’t been run yet. Any ideas??? Coked up turbo ??? whacked sensor??

21-23 psi at 75 seems kinda high without a load. good possibilty turbo vanes are stuck. one way i have heard to maybe check is from a stop go straight from brake to full throttle from a stop and see if the truck takes a little bit to get up and go if so then good chance vanes are stuck open.

[Jetmek319]

Thanks for the replies. I should have mentioned that the truck is running stock right now, no tunes applied and the numbers you see are without any load on the truck other than my sorry butt. It sounds like it is time to open up the turbo and clean out the burnt up gremlins.

[bondsman]

When mine were sticking, I could get on it and it would all go fine, let off and get right back in the throttle and I would have no boost and tons of black smoke with no power. I cleaned the vanes and deleted the EGR sys and it is perfect now

[VeeDubTDI]

Stuck turbo vanes... take it apart and clean it. Be careful applying full throttle, as it will want to overboost.

[jesilvas]

the trucks are set so that if it overboosts it either defuels or dumps the extra boost off