Ok first i am working on a 1995 2500 5 spd cummins. When the tank is below 1/2 full it doesn't want to start and you must prime it and push the primer 35-40 times and then it will fire, but when the tank is full it will fire right up no problems. Also when in 1st or 2nd and you mash it fast it pops and misses at high rpms but not in any other gear. Very confusing to me. Just need some help. he also has a #100 plate, 3GSK, and an HX-40.

Thanks
Cody

 

pops and misses b/c of low timing...need to bump the timing....its pretty much always the reason

when the tank is half full u mentioned that u had to prime it to get it started but it runs fine after that??? or it just won't run when its below 1/2 tank?

 

No after you prime it, it will run fine and full of power everything like normal.

Cody

 

dunno the answer to the 1/2 tank question but timing will resolve smoke...im sure someone knows the other issue

good luck

 

If I had to guess about the half tank thing I would be looking for a pin hole in the sending unit that is letting the fuel line loose its prime. Ya know covered with fuel when the tank is full but not when it is empty.

 

Robert Chilton is real close. What happens on these rigs is the hose on the fuel pick-up develops a crack about a third of the way up. Just pull the sender unit out of the fuel tank and replace that in-tank hose and your problem will go away. Total cost about $3 from NAPA for the replacement chunk of fuel line needed to do the job.

 

A leak in one of the metal lines on top of the bell housing will also cause the half tank syndrome. It can leak enough to cause problems without dripping to the ground. Crawl under the truck and feel around on top of the bell housing, if it's wet there's your problem.
Forget replacing the metal lines and just run diesel rated hose from the engine all the way to the tank