95 6.5 DUALLY. Started about a month ago. would be driving down the highway and would feel a miss/jerk occasionally @ a steady 55 mph. changed oil and filter, changed oil pressure switch and fuel filter. bled air and drained t valve. No help! Then things started going down hill. It would run great 30 min all the way to work then at lunch it would stall seemed to be starving for fuel. I would wait about 5 min and it would run like a champ.
went ahead and put another ops in and a new lift pump. seemed great for two days then started stalling at misl. times. going down hwy it would want to die and i could pump pedal and it would clear up. I jumped the ops (leaving it plugged in) and ran a wire to the fuse block so that the lift pump would run as soon as the key was turned on. worked great for two more days. i left work today went about 50 foot and it died. turn key on and opened bleeder on fuel filter and fuel ran right out opened the t valve and fuel runs right out also.
finially got it to fire up and had to pump the pedal to keep it running. if it dropped to 1000 rpm it would want to die it would not rev up over 2500 rpm. engine was fighting to run.
it only ran for about 1 minute and died. the waste gate was very hot to the touch and smoking lightly. when it was running for that 1 minute it was BLOWING black smoke.
This is a jasper engine with 30,000 miles
ready to go buy a old chevy truck with carb and points!! please help .

 

Sounds like you might be getting air in the sytem get some clear fuel grade hose run it from the fuel filter to IP look for air bubbles this would be the first thing I would do

 

thanks,
i will check into that this weekend. Is there any chance its the pmd, injectors or waste gate. small block nut, diesel greenhorn

 

PMD failure usually results in a runaway type symptom like it will rev up to 3000+ rpm's without touching the pedal where is you're PMD now located? does the waste gate move freely???

 

pmd is relocated and mounted on a heatsink with a ground to the body and the frame.
the waste gate slid one way easily but would not move back. I do not know how it works so i did not force it.

 

PMD relocated where ????? and waste gate is supposed to move freely when not running

 

pmd is located under battery box

 

That is better than on top of the engine for sure I would still get a piece of clear fuel line and run it between the fuel filter and IP worst case senario you will be out a couple bucks

 

My 6.2L had a problem bucking, surging and stalling a few years ago. Someone at the time suggested the clear hose, the same as you suggest. It worked great; we could see the air bubbles. My problem turned out to be where a body screw had rubbed into the rubber fuel hose above the fuel tank. It would allow air to leak in, but fuel would not leak out, so there was no other indication. The problem was initiated a year earlier when I had a crack in the fuel tank fixed and when they reinstalled the tank, they pushed the hose up against the body screw. It was really disheartening pulling the fuel tank down just to look for a possible leak there. Good luck! Hang in there!

BTW the 6.2L has a lift pump which pulls suction on the fuel line. If you have a pressureized fuel line from the tank, that would probably eliminate the above scenario as a possibility.

 

Runaway can be PMD but not the usual failure mode of a PMD, that said I don't suspect at this point PMD is suspect either.