I need help on trouble shooting my fuel issue
It have been having to prime since I bought truck
about 2 years ago.
I was having to do it only after sittin a few days (3 or more)
Now I am having to prime daily.
There are no visible leaks accept for the oil
How can I check or trouble shoot from tank to the pump?
what are some of the common problems with these trucks that are causing my issues?

 

Fuel lines and sending unit.

 

I would start by replacing any and all rubber lines. They are probably dry cracked and leaking air. The fuel will make them swell and they could be sealing up when the truck is running. Also try tightening your fuel fittings. Some of the washers could be dry cracked also if it sits for a long time.

 

^^ What he said ^^ You wont necessarily have fuel leaking but there can be very small holes that let air in causing you to lose prime.

Heres what my return line looked like:

 

Ditto on the fuel lines

 

Fuel lines. Could be sucking air

 

i had the same problem, it ended up being the return line off the injection pump the fuel line looked just like the one it the pic in the earlyer post.

 

thanks guys for the info
what is the best type of fuel line to use?
where is the best place to get it?

 

Any diesel rated fuel line. 3/8" and 5/16" I think.

 

Could be the square edged o-ring in the fuel heater bowl that can cause a loss of prime. And you have to buy the part at cummins