2002 ..5.9 ...3500 dually....has clean and new fuel filter, clean K&N air filter, no OBD codes but I have no turbo boost...it starts fine runs fine, but no launch when you floor it , like it had before....275K miles but only modest problems like VP44 replacement but since Raptor install it has been bullet proof....any help is appreciated. Doc

 

Could be several different things. Do you have lots of black smoke when you give it throttle? That might indicate an intercooler boot has split or come off. If it's just gutless with no other obvious symptoms then I'd guess it's running in limp mode for some reason.

Limp mode is basically the computer defuelling trying to save the engine because it thinks something's wrong--like it can't sense any boost, for example. If that's the case then there will be codes that you can see by doing the key on, key off (three times) check.

Mike

 

I have had a lot of problems with a intercooler boot blowing off, not really blowing off but blowing by which makes it tough to see. Lower right hand boot.

Rick

 

No codes, no black smoke..not defueling because it accelerates normally but I've lost the turbo launch...all hoses are tight..I'll check the waste gait this weekend, maybe it's stuck open?

 

The wastegate is a good thing to check. Also look for exhaust leaks between the head and manifold, and also between the manifold and the turbo.

It used to be not uncommon for 24v engines to lose exhaust manifold bolts, but I rarely read about it here in the forums anymore.

 

My boot clamps were tight but it was still leaking past one boot. Have you pulled the intake hose off to make sure the air filter did not fall apart and get jammed in the turbo?

 

The lower driver's side boot off the intercooler can rub against the inner fender and end up cutting itself open where the metal seams together.

On mine I took a pair of metal pliers and bent the edge out away from the boot so the sharp side wouldn't touch it. The factory boots will puff when you floor it.

Something to check..