Hello all. I have a 2002 F-250 CrewCab Lariat PSD. Besides a lift, Ranch Hand bumpers, aftermarket intake and a Magnaflow exhaust I have no mods.

On my way to work today the truck had problems during hard acceleration right at/before redline. Whenever I stomped on the skinny pedal, the truck would accelerate just fine, then hit redline and surge, sounding like it was getting fuel, then cutting it off, then getting it again. Also, a large puff of smoke that looked black shot out the tailpipe. I also got an SES light, but it would turn off whenever I turned the truck off. Repeating the event caused it to come back on. On another note, mileage was lower at 13.4 mpg when it was 14.3 just yesterday. It has consistently been 14.3/14.4 since I have owned the truck.

I went to Autozone to get the code pulled, but the SES light would turn off whenever I stopped the engine, so we were not able to pull a code, much to my chagrin. The code reader was an Actron OBDII AutoScanner. Maybe this is not a good scanner?

I am going to find a way to pull this code, that would make diagnosing this problem much easier.

Other than the problem at hard acceleration, the truck runs fine. I have recently replaced a bad black CPS with a grey CPS when the truck wasn't starting. Doing so fixed the problem.

 

Subscribing to hear what the codes end up being.
In the meantime, I would check the filters to make sure they are good.
No boost leaks, etc.

 

Just a thought, but does anybody know, do these engines de-fuel at redline?

Edit: I'm not willing to find out with mine,LOL.

 

When the truck surges near redline on a hard acceleration, the turbo makes noises like it is releasing boost, building it, then releasing it...almost like someone hyperventilating into a bag.

Yeah, I know. It's a bad description. LOL

 

You're defueling because of overboost.
The cure:
Overboost Annihilator

 

Ok, but would cause the engine to make more boost than normal?

Would it be the colder air? We just had an arctic cold front come through, maybe that is it?

 

Colder air is more dense and could add a little boost. At aproximately 22+ PSI the PCM will start defueling. 1 PSI increase can be enough to defuel. You can also get more boost at a lower elevation.

 

When mine defuels from overboost it don't surge,just shuts down for about 30 seconds

 

I live at sea level. However, the truck hasn't had defueling problems in the past. I'm certain that I won't be able to get Autozone to pull a code as I have read on here that their Actron scanners won't work on our F-250's. I am about to head out on town, so we'll see how she runs.

On another note, my truck doesn't give these symptoms for a 30 seconds, it just happens for a second until I let off the gas pedal.

 

Will a stock truck make that much boost? When I'm empty, I can only get about 18".

 

I think if the wastegate is malfunctioning (stuck closed) you stand a very good chance of getting over 22 psi at redline, full throttle.

 

I will research this wastegate malfunction.

I noticed that after the event my MPG went down real low, like at 12 mpg, but since I've put about 100 more miles on it the MPG has come up to 15.6 mpg.

 

Yeah, MPG is still fluctuating. Only started doing this when it got real cold. However, there has been no loss of power, though the truck will continue to do the above-mentioned symptoms on a hard acceleration.

 

I drove through a whole tank of diesel. I have consistently lower mileage. I'm guessing Exhaust Back Pressure Valve (EBPV)?

Any thoughts or consensus on this?

I'd take the defueling explanation as the reason why, but it doesn't make sense as to why the turbo would be making more boost suddenly without any mods.

 

What your describing sounds like the motor is defueling due to overboost. If your wastegate isnt working properly it could be causing you to have higher boost psi. The fuel economy is most likely the fuel your running. On winter fuel I drop a good amount of mile per gallon.Are you running diesel kleen or any additives?