Hey all, this is my second 6.5. I love the truck but its been acting weird. It runs rough after it warms up, the idle drops and sounds like its going to stall when stopped in gear, small puffs of white smoke and possibly a miss fire if i step on it lightly, clears when I gun it. Already moved/replaced the PMD and put in a new fuel filter. The inline pump is also working properly. Any idea what it could be? I'm thinking maybe the injection pump or the injectors.

 

Sounds to me like the IP timing is off.

 

Theres a scan tool and special procedure to adjust it right? Never screwed around with timing, probably wont attempt it either

 

Yes. Scan tool needed

 

Tech 1,Tech II with OBD1 expansion module or GMTD ScanTech(laptop program and cable) are what must be use to to a TDCO relearn on 94/5.

I would start with replacing the IP fuel return line with a piece of clear diesel rated hose and with the truck safely parked and idling-watch that new line for bubbles.

Bubbles in the return line indicate air infiltration in the fuel supply.

With a properly working LP the air enters between the fuel level in the tank and the LP,if the LP is running but not pumping the air can get in anywhere.

To test the LP idle the engine and open the water in fuel Tee-valve,if the engine stalls the LP is not adequate or not working.

 

Well its not the lp, just went out and cracked the t valve with it running, didnt stall and shot a good amount of fuel. Where should i look next?

 

What about the IP return?

Injector age?-after 100,000 miles injectors should be rebuilt/replaced with Bosch nozzles ONLY.

Timing might need addressed?

Is the optical sensor electronic noise filter still installed?They become defective and can be completely removed as long as you encase each OS wire with ferrite core from radio shack ect.

 

Going to try the return next, as far as i know the injectors havent been touched, truck has 195k on it. Which line is the return, the one under my thumb or pointer? http://s12.postimg.org/eoc6y59ct/20131012_180712.jpg

 

Return is under your thumb-frt fitting on IP.

 

OS electronic noise filter,unplug and remove filter plugging the main harness back into the OS when time permits put ferrite core over each wire for OS: