I got my truck about a year ago, it's a 97 12-valve, and each time I drive it a couple hours after I turn it off it loses its prime. Whenever I want to drive it, I'll start the engine, it runs for 30 seconds then dies, and then I have to manually prime it to get it going. I've already bypassed the fuel pre-heater, replaced the overflow valve, replaced the lift pump, and replaced the rubber return fuel hose. I can't see or feel fuel leaking anywhere....Any suggestions? Thanks!

 

When you replaced your fuel lines, did you do all of them or just return line? If you haven't done all of them, I would suggest doing that. Also, take a look at your fuel filter and see whether it is leaking. The way they are constructed, they sometimes leak around the top lip.

Another thing that I didn't see you mention was the sending unit in the tank. They can rust out and introduce air as well. Since your truck starts and runs for a while before dying, it sounds like you are getting air bubbles somewhere slightly farther away than the engine. Most people with air troubles can't get their truck started in the first place.

 

Yes Yes Yes the sending unit in the tank I have done mine and a buddies www.RockAuto.com
Brandon

 

Did you replace the lines from the pump to the tank, or just the rubber short lines? The metal lines also develop cracks that will leak air in, but not fuel out.

 

Yeah I run 5/8" Not Stock Ha Ha.
But good point I would re-run them all rubber IMO.
Brandon

 

thanks everyone for the advice