So today I helped a buddy change the lift pump on his wrecker, pump was only putting out 2-4 PSI, and the truck was down on power. First off what a pain in the ass to get to the pump and filter on the damn thing(I'm used to my IDI) After some good cuss words, I got the pump chaged. Bled the system, and got it fired up.
Now, for problem..

After running a for a minute or so, the truck runs out of fuel, however, when it dies, one can keep it going by pressing the primer button..
When I crack the bleeder on the filter head, a good amount of fuel comes out with the primer button, however, little to any comes out when the engine is running.

So basicly, that leaves me with the new lift pump, is not pumping??
Is it possible to install it wrong? looking at it tells me no.. but I really don't know?
Anyone have any suggestions?

it's pretty difficult to install wrong but there is a rubber o-ring that sometimes does not seat completely which would cause a loss in pressure. Only other easy mistake would be not engaging the pump machanism. Other than that it might be a bad pump.

-ben

is the filter pimed? alot of times you drain off all the fuel in the system when you cahnge those. crack the line at the P7100, and crack the line going up to the lift pump pressurize the fuel tank with some air when fuel comes out at the lift pump tighten the line and start pressing the primer, you should have to pump 30-40 times to get fuel to start coming out at the back side of the P7100.


you other option crank and crank and crank the bastard over until it fires and coughs then pump the throttle and keep the rpms up. most likely you have air bubbles int eh system and in the fuel filter causing it to die after a minute of running

not un-common yes they are a pain

Only other easy mistake would be not engaging the pump machanism. Other than that it might be a bad pump.

-ben

how does one pull that off? I'm assuming the rod that runs off the cam? It was allready installed in the new pump, so I wouldn't think so.. but I guess who knows.

either way, hopefully I'll figure it out today, but my money is on a bad, new, lift pump, being tha it will run indefinately if I just keep priming it.

well, found the problem... the push rod for the lift pump snapped off.. wtf.. Everything seemed to go together fine, but obviously not..

Anyways the new pump will be here on saturday..