12 valve lift pump issue HELP
 

i have a 95 12 valve cummins and have jus replaced my lift pump. The truck run fine at idle but when given fuel shuts off. At idle though iv noticed fuel coming from in between the pump and block also ckecked both lines they do not leak, i know jus from that it'll shut off cause its sucking air. Anyonoe know if fuel pump is bad or what my problem might be??

anyone ......help?? please????

If its leaking somewhere - that will be the first thing to fix. Then see what happens.

What rpm is it idleing at? (in gear)...

well its idleing jus like its always done i have had it tore apart since june cause of the kdp before i replaced the lift pump it would idle jus fine but when hitting high rpm it would act like it was getting no fuel. i went to local part store bought new lift pump and when cranked itd idle jus fun in gear and out but as soon as i go to speed up it gets no fuel and i would have to re prime my lines. fuel was coming from in between block and pump not from no where else. is there maybe a gasket in between the block and pump cause the old one didnt

:humm: Well I would buy a new seal for in between the pump and block first. The way it sound's is that it has enough fuel supply at idle but when you put throttle is it starts sucking in air instead of fuel that's why you have to prime the lines. That my best guess. But like i said try fixing theleak first. I hope that help's some. good luck :tu:

If there's fuel coming from in between the block and liftpump the pump is junk. If anything were to leak there it should be motor oil, but before you go for another pump be sure it's not the heater bowl or a line thats leakin, and yes there should be 2 gaskets, one between the heater and block and one between heater and pump. :c:

yes, there are a lot of places where it could be leaking (or letting air in) which causes you to lose prime in your fuel system

on my 94 at 250k i replaced pump because i thought it was leaking and after, found out it was a bad fuel line.

Its very common for the return line to leak fuel

where might i be able to get a new or used cheap line that goes from the pump to the filter since my line stripped on me?