Hey guys, this is actually my brothers truck. He doesn't think anything is wrong and says the truck has run this way since he has had it. It feels like its running fine as far as stumbles/misfiring goes, it only has an EGR delete, no tuner or anything. It has 37" tires and thats it.

the problem:

when we tow his boat (#5500 empty) we cannot get over 60-65mph.

truck tops out at 80mph unloaded



This does not seem normal to me, even with the extra gearing from the tires, I do not see any reason these trucks shouldnt be able to pull that weight. Am I just over estimating the capabilities of this truck? He told me he recently had a tune up about 3-4 months ago, which included a new fuel filter, but this was an issue prior to that as well. no CEL. unknown if there is stored codes.

 

Something is wrong for sure. I can tow my 5th 8000lb 5th wheel up hill at 80mph easily. What kind of filters? These truck are picky and you should only use motor craft filters. I really dont know why it would top out unless they have some rev limiter or something. But as far as I know they dont. You should find out if it has any CEl codes or if theres smoke on start up are any other time. Any other mods done to truck? How about the air filter? hows that look? Im sure more will chime in soon and we can then help you pin point the problem.

 

I havent gotten to take a look at it, I am going to be heading over there in the morning and was hoping to have a few places to start and check simple stuff. I was hoping maybe it was just a charge pipe that blew off and was just losing boost but he said he hadnt heard any abnormally loud spooling or wooshing.

are they OBD2? or is there some other type of scanner i need for the diesels? i know people seem to like the sct but if he is keeping it stock, there really isnt much of a point to drop that sort of cash.

and no other mods other than the EGR delete.

do they have issues with the turbo and the variable pitch?

 

Yes they use the OBD2 scanners. Could be a hole in turbo pipes? If you have an AMMCO near you go there. Just say your CEL light keeps coming on and off. They will check for free.
The turbos do have issues if the truck doesnt get driven much. The vanes can stick which would cause low boost and or low MPH. I didnt even think of that before. There should be a sticky above for turbo cleaning also. And the normal boost at WOT (wide open throttle) should get to about 24 to 28.

 

What year truck is it? Does it blow any smoke at all? Something is definitely wrong with that.

My buddy ran 37's on his with stock gearing, with just a tune it would roast the 37's off like stockers. Granted, stock tuning will be much slower, but it should still turn them with ease.

Need more info about the truck. How long has he owned it? How many miles on it? What kind of fuel filters are you using? How about oil and oil filter? What type/make?

Is there a boost gauge in the truck? (this would be 05+ trucks only) and what's it reading?