i keep losing prime

[Brianedwardss]

Yeah. The check valve being stuck open allows air from the return system to enter the supply side of the fuel system, and prime is lost. It doesn't take much air to stop the IP from pumping. Air in the return system isn't a huge deal on a 7.3L, because they have that check valve. But if the valve is not working, then theres problems.

 

[junior20762003]

a man thanks alot i really do appriciate the help i was about to buy a injection pump later today but can you point out the left pump for me thanks tho alot

 

[Brianedwardss]

No prob.

The lift pump is directly under the vacuum pump on the passenger side of the engine.

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Center of the picture, this is looking at it from the fan/grille area:

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Close-up, two bolts hold it in. When putting the new one in, the arm needs to be under the cam. Only way to get to it is laying on the ground near the passenger front tire.

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[burt]

My last hard to find air in fuel/loss of prime problem was the check valve in the lift pump. Not sure if its always like this but would only lose prime with vehicle pointed up hill. Flat or nose down would always stay primed

 

[junior20762003]

well guys i went to my local ford dealer and the guy who worked in parts department didnt wanna order me the part instead he insisted on me just jb welding them damn thing to plug it off so i forced a allen key thru the hole to seal it and still the same issue it`ll get air in the system and fall flat on its ass anymore info before i get a damn injection pump

 

[junior20762003]

ok so injector pump is my next choice

 

[smokin90]

what is the normal fuel pressure that they should have sometimes i have to crank alot to start i was thinking about putting an electric pump on any suggestions

 

[Clydesdale]

Check for air everywhere in your fuel system. I dropped my tank and worked out from there. the root culprit (I had issues in tank as well, after that tank surgery it would hold prime if I didn't run it), was a lack of teflon tape on the inlet side of my e-pump.

Teflon taped that, and lost all my prime issues, hard to start vapor lock type issues, the whole ball of wax. Became a brand new truck, so to speak.

 

[Brianedwardss]

Replacing my check valve with a new one from ford made my truck seem like a new truck. No more start-then-stall ever again

 

[smokin90]

ok thanks alot for the help but just to know for the future what should the the fuel pressure be at the filter housing and i also have another problem you take the engine to about 1000 rpms and the engine sacks bad but any other rpm its ok below or above 1000 rpm

 

[junior20762003]

Hey guys I found my issue its the fuel line does anybody have a part number for it. Its the one that runs in the frame from the fuel selector to the lift pump.

 

[rhkcommander]

Not to hijack but are there check valves in 87 and older trucks? I'm losing prime with a new return line kit and electric pump. The filters get air in them . Everything except the e-pump an rubber hose to and from it and the napa fuel water seperator I've added.

Thx

 

[Brianedwardss]

^ My 87 doesn't have a check valve, but the 88 does.

Something I'd try with your 87 is install a clear line from the filter head to the return cap. O'Reiley's sells the clear line on the shelf for just a few bucks, it's in a slim red box towards the back center iirc. That way you could watch and see what directions the bubbles come from, supply or return side.