Hey everyone been going through the motions trying t0 diagnose the issue on our one ton dually. It all started about two weeks ago the truck is getting harder to start, and going down the highway anything above 45mph the truck starts bucking/ surging hard enough i thought for sure we were going to break the drive shaft has the same issue with the cruise set also coming to a stop I push in the clutch and the motor revs up and wont return to an idle unless i put it in gear and dump the clutch, we put new glow plugs and injectors in and the issue is still there any suggestions?

 

Going to need to know year, more info like recent service history, miles, etc would be handy to.

 

1994 225k miles new injection pump about 1.5 years ago we have 2 gas pedals with the sensors did it with both we tried driving it with the drivers side injectors replaced that's when the issue was still there however we haven't got it back together with passenger side together 3 of the 4 on the passenger side were stuck open so hopefully that may be the problem? do you know how I can test if the pmd is bad as well? Also the turbo had a lot of sludge in it.

 

i would be curious how much of its own oil it is consuming, might have a bad depression regulator causing it to free flow blow by gasses and oil into the intake. i am not aware of any way to test the pmd unfortunitly, maybe someone else can point you in the right direction. They are kind of the box of a 1000 mysteries and they seem to more often than not cause funky drivability issues.

 

my other question would be have you opened the bleed on the fuel filter while its idling? does it die? or does fuel fly out?

 

The fuel flys out.... I'm curious to see if all the new injectors fix the bucking/ jerking when it gets over 45 it rolls coal all the time I need to get the injection pump dynamically timed might make it a little more fuel efficient when it gets to running right I've ran it a little longer than I should without changing the oil I will inform you of how it runs when its all back together with an oil change the turbo has been stuck and not spinning freely lately is that due to the sludge I found?

 

the turbo is fubar if it wont spin freely. it is bucking because it cant get exhaust past the turbo or air in past it. that answers all your problems right there. take off the oil feed and drain and run solvent down through it and pray. i would also take off the compressor housing and clean it out to if there is sludge in it. until the turbo is addressed you are pissing into the wind.

 

with the air filter off and engine idling the compressor wheel should be hauling *** around in there, they have to spin very free to be able to do the kinds of rpm required to make boost efficiently.

 

After cleaning the turbo spin's freely by hand. Have to hook exhaust back up but I do believe the compressor should be hauling a**. I can turn it with my finger. Thank for all the help

 

awesome! sorry i dont have a more accurate number than "hauling ***" but i dont have a tach on mine. a guess would be 1000 rpm at idle? i believe they run 10-15k when producing boost. all guesses but i think you get the idea. another thing you might want to check while there is they came with soot traps that get plugged up.