I seem to have a starting problem that I need a second opinion on. When I first put the cummins in my truck it would start instantly hot or cold when you hit the key but it slowly stopped firing up instantly and now I need to touch the pedal to get it to catch, once it's going it runs really strong and pulls like crazy. I drove it yesterday but since it seemed to be getting worst so I decided to park it nose down over night and try today after installing a fresh filter. when I removed the old filter it was only 2/3 full which seemed strange so I prefilled a new filter and tryed starting a couple of times and it didn't seem to want to fire at all so I pulled the lift pump and it has lots of suction at the intake side when pumped and I can't blow backwards thru it. I reinstalled and pumped it but the pump lever is very slow to return to top and seems like the diaphram is sticking (It worked great when it was out). any way it started but I had to hold the pedal half down to get it to catch. Took it for a spin and it runs and idles great. Sorry for the long post, Any ideas?

Grant

 

Sounds like you may be getting air in the lines, even if you don't see fuel leaking. I'm still only limited to experience with one pump, but most pump problems I've heard about involve fuel leaking. By the time you eliminate the fuel lines, the pump ghuru's should be waking up

 

I replaced all the lines with new from the sender fwd, but am begining to wonder if maybe there is some sort of problem with using the Gas sender and tank. It sounds like other guys have done it without any probs though. I will double check my connections tonight anyway thanks.
Grant

 

Today I took both lines off at the engine and stuck them in a bucket of diesel after pumping it for a bit until I saw minimal bubbles coming out the return line, it fired right up. I let it sit for awhile and it still fires up instantly, sooo I hook up the fuel line back up to the truck and start it and I am getting tons of air coming out the return line so I think that I have a cracked metal line inside the tank on the fuel sender assy. Going to pull tank and sender to verify.
Grant

 

I don't think that the problem is in your tank, because it would have to be drawing air up through the return line from the tank into the lines on the engine. I would look for a leak in the lines up on the engine -- maybe the line to the top of the pump and the fuel filter?

Please let us (me) know what you find!

Alec

 

I pulled my tank last night and discovered the problem. I am using the gas fuel tank and about halfway down the pickup tube is a piece of plastic line that it looks like sombody has tried to fix in the past and overheated it trying to push it back onto the metal line, Anyway it had it tiny little split in it so that when my tank got around the halfway mark I started to suck a litlle bit of air. I replaced the sender and it fires up instantly once again. Redleg hit it on the nose when he said I was sucking air. Thanks

Grant