Do P-Pumps Knock When Going Out
 

I have been having problems with fuel delivery on my truck. I haven't been able to figure out what it is, but tonight when I was in the driveway it died. When I started it it started to knock on the pump side. I couldn't tell if it was the p-pump or the lift pump.

After it was knocking it died after about 15 seconds of running. I primed the lift pump and it stoped knocking but it was still very hard to start.

1994 12 valve

any help before I take it in would be great

soundls like your getting air in the lines

I had the same problem just a few days ago.. Iagree sounds like air.. You can get a piece of clear hose and splice into the fuel line and start it up and see if there are any air bubbles in it to make sure..

just replace all the rubber fuel lines i know there are 4 for sure to on the pump and two by the tank

I did splice a clear fuel line in and it didn't have any air. I also checked the pressure and it was fine

They go out? lol

This is bs mine started knockn for a short second yesterdat it was breif couldnt tell if it was valves or pump:argh: im adjustin lash regardless did ur pump go out yet?

I have a 12 valve also and mine you will be on interstate and interstate only and it will loose power start with a peck on the injection pump and will try to die out having seem like air is in the line. It only does on interstate but idk if its supply or plunger sticking also throttle seems to lock while it is pecking

Deff. Air in lines

Thread is 2 years old :w2::s: