Fuel losing pressure / bleed off

[BHerring]

Greetings all,
I have a 1993, and I recently had the VE pump re-build and installed re-built injectors (upgraded injectors to 5 x .012) OK, so once I get her started she runs like a champ, no loss of power, just normal, runs like a champ! I seem to be losing fuel pressure, if sitting over night on an incline, (driveway) it takes a bit to get her running. What I have done.

1. replaced the fuel lift pump
2. removed the input fuel quick dis-connect and installed hose with clamps.
3. I removed the return line quick dis-connect and put some compressed air (about 10 psi) into the return line going to the injectors, heard no air escaping from the return line.
4. I removed the input quick dis-connect and the fuel lift is hold the fuel, there is no fuel leaking back to the tank.
5. Replaced the fuel heater gasket, and the fuel filter is nice and snug.
6. I have primed her many times, no air coming out of the bleed screw, and no air coming out of the return line (i removed the return line disconnect and primed her) nice flow of fuel.

There are no leaks of fuel anywhere! this is really getting to me, almost forgot, when I have her level and she sits over night, much easier to start, but can still tell I lost pressure.

How can I troubleshoot this?? How would air be getting into the fuel system?? Very confused. I am thinking I might remove the fuel pre-heater for test, (I live in San Diego, dont need to worry about freezing climate)

Any and all information will be greatly appreciated.

BH

 

[petersonj]

I don't know all the details of the VE pump fuel system, but I can assure you that you are on the right track. When the truck is on an incline (assuming the front is higher than the rear) fuel will always try to drain back to the tank. If there is even a minor leak on either the supply line or return line, a symptom that will most likely show is a hard to start engine. You will not see a fuel leak because fuel is not leaking out - air is leaking in, slowly replacing the fuel that is draining back to the tank.

Someone else will probably respond shortly with more details on how to troubleshoot your fuel system.

- John

 

[BHerring]

Thank you, Yes when parking on an incline, the Front is higher than the rear. I need more troubleshooting tips...I am waiting for the pre-heater delete nipple to arrive, I am thinking that is my next step, I dont trust that new gasket and that pre-heater is plastic and might have a hairline crack or something. Hopefully that will take care of the problem.

 

[DVolk]

Did you replace the quick connects at the tank ? Also even though you replaced the lift pump could be a bad one oil ring culd of went bad were they installed wet or dry

 

[BHerring]

Hello, I removed the pre-heater and still having issues, today will the day I replace the lift pump (got a good one from Geno's) and if that doesn't fix it then I will be replacing the quick connects on the tank. Question do I have to drop the tank to replace those quick connects?

 

[DVolk]

You have to take the straps loose ,if your hand is small enough you might be able to get under the bed ,or you could loosen the bed and block it up if the crossmember isnt in the way . Did you double clamp the fuel line thats what i did on mine

 

[BHerring]

No, I did not double clamp, but I will, that's a good idea, no time today to install new lift pump, first lift pump the I am going to losen those damn fuel tank straps!

 

[DVolk]

Id pre soak those strap bolts with a mixture of ATF and Acetone so they wont break off , although if there is a kid around with a small arm they might be able toget up there and do it . Also did you also remove the return line quick connect ?

 

[BHerring]

No I have not, I busted open my middle finger tip with a drill bit, so I must now wait a few days for my finger tip to heal, but no I did not remove the return line quick connect, that is on my list, speaking of those, cant I just buy they replacement connectors and re-install them?? What is your take on this? Also what about the the fuel return check valve? Could this be bad? your take on this? Want to leave the gas tank alone until I have done EVERYTHING forward of the tank. Then I will tackle the tank, because if I am going to mess with the tank, I might as well take out the sending unit and replace all those "O" rings also, do you agree??

BH
San Diego
[h=1][/h]

 

[DVolk]

If you did not touch the return do that i bet thats it . i see those quick but there not easy to put on id steer clear of those

 

[BHerring]

Ok, I think I should be able to take the return off quick connector and replace it with hose and clamps, and you suggested to put two clamps on each end, and I will do that too! I think my finger will be ok to do that today!

 

[DVolk]

Tape up your finger it should be fine

 

[BHerring]

Taped up my finger, still hurts, downed a fifth of JD so I am ready to work, removed the lift pump and guess what I found, a crack on the input side, on the bottom of the input. Could not see this when installed, removed it, ****** on it, installed new one, and my problem has been fixed. What I a pain, but now I know that fuel system inside and out.!! Thank y'all for all the suggestions and ideas, was sucking in air...with no leaks....so I am one happy redneck now!!!! WOO HOO!!!!

 

[DVolk]

Glad to help