At work we have a 1999 F350 dually w/ the 7.3 L diesel. It seems to run OK until it hits 2200 RPM (2500 RPM when the engine is cold), then it has a high pitch whistle and completely stops accelerating. If you lift of the the accelerator, the trany shifts and it accelerates again until it hits 2200 RPM. If you're driving and hit the gas, it downshifts and doesn't accelerate. Top speed right now is about 65 MPH, and drops like a rock going up hill.

The truck only has about 55,000 mi and has recently had the fuel filter changed. We just got this truck transferred from another office that has all but closed, so I can't get any history of the vehicle.

Does anyone have any ideas what the problem could be? It isn't throwing a code, and no idiot lights are on.

 

You are experiencing problems as the turbo is trying to kicking in.

Either they never let the turbo cool off and it is cooked or somewhere in the pressurized intake you are loosing your boost.

i hope this helps.....

 

Check the intercooler hoses going to and from the Turbo.....been known to blow off due to defective clamps.

 

My first thought was the turbo had gone out, but wouldn't it kick in way before 2200 RPM?

 

It's spinning but not creating boost until about 2000-2200rpm.

 

I'm not a diesel guy, but make sure the air filter is clean. Pull the intake tube to the turbo off and peer inside; I've heard that people who let the air filters go in the 7.3s eventually wind up with trashed turbos.

 

You don't have a turbo problem, you ahve delivery problem somwhere. That truck should not have come with an intercooler. The turbo should start making boost around 1300-1500, as there is not much usable rpm for the 7.3L. It is hard to say what the high pitch noise you are hearing is, but it does sound like you are not making boost. I would check all you plumbing for the turbo, oil lines for the turbo, and all your exhaust manifold bolts. Hopefully nothing major.

 

Midnight,

From 1999 on the PSD has an intercooler.....and it is a common area for concern since the hoses sometimes blow off under pressure/boost. Ford addressed the issue with revised hose clamps and repaired it under warranty. The PSD routes it's crankcase gases into the turbo intake side just after the airbox. This introduces a fine coating of oil inside the intercooler and it's hoses and this contributes to the previous clamp failures

Check out this site for all Ford Diesel related topics:

http://forums.thedieselstop.com/ubbthreads/

 

i dont know much about diesel either....but i would look into the catalytic convert if diesels even have those.....that would choke the motor pretty bad if its defective

 

quick and simple check for the turbo is to pull the intake tube off and look at the fins. make sure there isnt excessive oil there, broken or damaged fins. like was already posted check out your air filter to make sure its clean.

do you get anykind of smoke at the tail pipe? if so what color?

 

will do when I get a chance...
the best I can tell (from looking out the mirrors) is their isn't any smoke coming out of the exhaust.

 

Diesels do not have catalytic converters, just a resonator and a muffler.

 

What type of waste gate does this motor have, could it be the problem?

 

I'm betting on a leak in the plumbing. After cleaning all the boots, one trick is to use a little hairspray to help the clamp hold the hoses.

Sorry, all superduty trucks have a factory intercooler. You can see it below the jack stuff in this pic.



Again sorry but it depended on the year and what tranny you got. Usually the autos didn't have a cat, and usually the manuals did.

Adrianspeeder