I recently acquired an 83 C20 with a 6.2l that had been sitting for about 8 years. I put a new fuel filter on it and got it fired up without much effort. It produced a lot of smoke but i expected that from the old diesel in the tank, but overall, it ran pretty good.

Not wanting to run it much on the old diesel, I drained the tank, and put in 5 gal of fresh fuel. I fired it up and it wasn't long before it seemed to run better yet and i decided to let it idle for a while and get good and warm.

After about 1/2 hour, it shut off. I started it again, but the idle was really low and the throttle response was weak. After coming back to it the next day, I started it up, and the throttle response was even worse, and after 5 minutes of running, it would only do about 2000 rpms with my foot to the floor and would die immediately when letting off the throttle. I changed the fuel filter again, no change, and now I can crank it with my foot to the floor, it will start for a second and then die.

Seems like a fuel, or lack there of problem. I pulled the fuel line off the filter from the pump, and it seems to be putting out a solid steam of fuel when cranking.

Added info - after reading some other posts in here, i realized i left out a couple things, the engine has no mods, and I did advance the injection timing slightly a week ago, after reading that this could help with smoke issues. I moved it maybe 1- 1.5 mm to the drivers side.

Any help would be greatly appreciated.
Thanks,
Sam

 

Check all your fuel return lines on the injectors, they are just small rubber hoses and after that long of sitting could be cracked and allowing air to enter the fuel system causing the problem

 

Thanks, i will check on those return lines. I was looking at them the other night and there are signs of deterioration.

One other note, i decided to take the cover off the injection pump just to inspect (it was full of fuel) and i moved things around to make sure they moved freely. I put the cover back on and it fired right up and ran with good throttle response for about 5 sec and then back to no fuel. I repeated this three time with the same reaction, run good for 5 sec then die.

Maybe playing with something allowed more fuel to get into the pump for a short moment?