Cummins Driver
06-12-2009, 02:56 PM
Hey guys. Dad has an old 4320. We have had it for a little while. It ran fine when we got it aside from a little blowby, but now, you can start it, and it will hardly idle. It sputters, misses, and puffs black smoke, and will normally die after running it a little. Im pretty sure the lift pump is just shot. We changed the fuel filter, and primed it the best we could and it started and ran good for a minute, and then went back to having no power and barely running.
So today, I took my fuel pressure gauge, and pulled the bleed screw out of the fuel filter housing, and threaded the line to my gauge into it. I fired it up, and its only showing between 0 and 10psi no matter what RPM, and it is very erratic. The needle bounces up and down the whole time. I need a needle valve to stick on it to calm down the pulses, but I still think the lift pump is probably shot.
Im not sure what the factory specs are on fuel pressure. If anyone can help me out with the factory specs, I would appreciate it. Thanks
Eric
So today, I took my fuel pressure gauge, and pulled the bleed screw out of the fuel filter housing, and threaded the line to my gauge into it. I fired it up, and its only showing between 0 and 10psi no matter what RPM, and it is very erratic. The needle bounces up and down the whole time. I need a needle valve to stick on it to calm down the pulses, but I still think the lift pump is probably shot.
Im not sure what the factory specs are on fuel pressure. If anyone can help me out with the factory specs, I would appreciate it. Thanks
Eric