6.5 liter turbo diesel major issues
 

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?

:td: 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. :td:

with the air filter off and engine idling the compressor wheel should be hauling ass 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 ass" lol 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.

Thanks Josh for all your help learning more every day. Where would the soot trap be located?:humm:

It looks like the catalytic convertor off of a gas engine and its basically between the transmission and frame on the passenger side. They don't all have it and if it did hopefully someone cut it out already.:hellox:

His being a 94 Dually with F engine should not have the 'soot trap" but if it was a CA Smog truck it may have one, the one on my K1500 "fell off" years ago :)

:tu: yup, just one of those things that should be looked for. my 95 1 ton dually had one on it when i got it. Also had 4.56 gears which people thought was strange too.

I "found" mine a while back when it "fell off" it landed in my shop on a shelf, just in case I ever found a need for it again :)

its funny how stuff just falls off huh? :w2:

Alright guys, the truck is all back together new glows plugs and injectors hardly fixed the bucking. I ordered a new accelerator sensor it helped a little bit. Put a new lift pump in fuel shoots out of top of filter as before it just barely ran out that helped a little ordered a new pmd..... Plugged it in starts engines revs sky high???? plugged old one in engines run fine but acts like it has a miss..... started taking a gander at the injection pump since people may think my 2 YEAR OLD injection pump is bad i started playing with some wires plugged new pmd in and truck runs fine WTF? What i unplugged was the optical sensor code thingy on the top of the pump ran her down the highway a little hesitation but nothing like it was..... no more bucking no more rpms going sky high when you arent pushing the gas pedal down when you have the clutch in no more sounding like shit it sounds good i came home plugged that back in took it for a cruise and once again it sounds great and drove better than it has in a long time the little bit of hesitation is what gets me what can i do to try to get my problem all gone?

If you unplugged a sensor and it improved i would suspect there is corrosion in that plug, if it was me i would spray it out with electrical cleaner, dry it, then reassemble making sure it is fully seated. Could also inspect the wires around that area and see if you disturbed something else on accident that is having poor contact or a wire that is damaged.