Engine runs rough
 

'94 2500 6.5L 230k miles manual trans. Replaced engine from '98 with 40k miles '98 truck ran great lots of power. Installed intercooler with engine replacement. Runs rough when first started about 2 minutes. After warming up step on accelerator and get lots of white smoke then quickly turns clear. Runs good down the road occasional bucking. Throttle up while driving lots of black smoke for few seconds when turbo spools up very little smoke. Engine bucks bad while accelerator is pressed and stops bucking when accelerator returned to normal driving position. Installed new injectors. Remote PMD. Took truck to standyne dealer worked on it for a week could not figure out whats going on. He pulled all injectors on driver side and they all tested good. I do have concerns that the shop that changed the engine did not get all ground straps back on.

well there only 2 ground strap and that at back on right side right below the A/C dryer one goes from firewall to back of right head and the other from firewall to the frame right behane the front right wheel

the white smoke from cold start maybe bad glow plugs

for the black smoke maybe from turbo trying to keep up with inner cooler these GM turbo are small how much boost are you running

6.5 runs rough additional info
 

The white smoke occurs after the truck has warmed up and been driven awhile. Today I changed the fuel filter and was not able to get much fuel out the top of the new filter. The truck was hard to start and keep running for about 2 minutes. Opening the top of the fuel filter with the truck running there is no fuel and after about 10 seconds the engine quits. If you hold you finger over the bleed there is suction present. Hard starting again with the filter bleed closed and then runs so so. If you open the drain valve on the thermostat housing no fuel there either and dies after 10 seconds. Suspect the frame rail pump. Checked voltage to pump 0 volts with key on voltage comes up to about 9 volts while cranking and goes to 12 volts when key is released and after about 3 seconds falls to 10 volts. Hooked a battery straight to pump runs good plenty of flow. Good flow to filter bleed and thermostat drain valve. Truck still runs rough did not run more than 30 seconds. Might have air in system because of frame rail pump issues. Thanks for the quick reply!!!!

sound like bad OPS put 12v right to LP see what happens

You are correct. OPS was bad. Replaced OPS all is well. Asked shop why he missed the bad OPS he stated that no code so it was not checked. Now I'm having oil pressure problems. Engine ran 55-60 and idle press was 45. Now oil press is 30 driving and 8-10 at idle. Will replace oil filter tomorrow and see if that corrects the problem. Thanks for feedback!!

did you replace it with AC Delco

No I replaced with the one on the engine we pulled out of the truck. This morning that switch also failed. Purchased switch at NAPA but have not installed it as of yet. Question on this oil pressure problem. We installed an after cooler on the truck and my mechanic said there was no room for the oil cooler and thought that removing the heat load of the turbo, the oil temp would be ok. He plugged the taps in the block and I'm not sure how the oil flows through this engine, Maybe this has something to do with my oil pressure problem.

all the 6.5 have oil coolers

If you replace OPS you want to go with AC delco

No oil temps would not be ok if you plug the ports 6.5 need that oil cooler