08 250 running like crappola... Ideas???

[vr6dub]

Sooo, I have a strange issue. When I'm on the freeway doing 65 and I floor it, it never downshifts and stays in 5tc and slowly accelerates while kicking out a smoky trail, never cleans up. Will only downshift when I slow to 50-55 then it seems fine, I guess. Boost never gets over 44 no matter how I roll into the throttle, slowly or fast, up hill or on level surface. Defuel for boost is set for 50.Things I know is no boost leaks, boots are good, no turbo issues, VGT works as it should, intercooler is not full of oil, no codes, dealership has gone through it mechanically and cant find anything, and the last repair being a bedplate seal replacement.

Truck has the normal deletes, No Limit Intake + CAC with egr deletes, mini-max with custom tunes. Never noticed it with the stock HD tunes but also never really experimented with the stock tunes either. Is it possible its a tuning issue and if so who all is tuning for the H&S? I know not to go with KEM, so that's outta the question. Any thoughts about it being mechanical with the truck I might not know about or Ford might have missed?

So what do you guys think? Any help is greatly appreciated.

 

[ckrueg]

What rpms are you running at 65?

Sent from my XT907 using Tapatalk

 

[vr6dub]

It's under 2000, maybe like around 1700 or so. I have 3.73 gearing with 35" Nitto MT's and the H&S RPM is set for 35.75 revolutions to get my speedo correct.

 

[Dzchey21]

whos custom tunes are you running?

I would update your minimax and then try some canned h&s tunes and see what happens

Its not super uncommon to only run 44 psi just depends on the tuning

 

[vr6dub]

I'm on Gearheads tunes now, H&S has been updated, SD card reformatted and everything reloaded a couple times now. Been having this issue for a while now. Was going to load the canned tunes and see if there's a difference. The main reason for dumping the canned tunes was how smoky they were during normal everyday driving.

 

[Dzchey21]

ok good to know.

Have you checked to make sure that your back pressure sensor isnt plugged or even the map sensor being good? Matts tunes are usually pretty good. It might be time to inspect the chargers

 

[vr6dub]

ok, thanks for the place to start, I'll check those out this week. The turbos have been checked out and nothing found to be wrong, bellows check good as well. Thus the wtf because it seems like all the hard parts I would assume to be bad aren't.

But again, would one of those two parts cause the issues I'm seeing with the trans not downshifting? It just doesn't **** and get like my old 04 did with Vivian's Looney tunes. On her tunes I could be cruising @ highway speeds, step on it and it would downshift and go. This truck just sits in the 5th with TC locked and gradually picks up speed while smoking its butt off the whole time. Both truck had the 3.73 gearing but the main difference is the 04 was lifted 8" and had 37's on it and the 08 is on the 35's and lifted 4's.

Starting to make me regret getting an 6.4 instead of going back to the 6.0.

 

[Stroked777]

Possibly a trans issue. I know with my gear head tunes if you punch it it will down shift into 4th tc locked and pull hard, and the most I get is a light haze during acceleration. check and see if there is any codes. Some times they pop up and don't throw a light