huh ... that is truly odd ....

is your pick up tube and feed line the same size I.D. ?

Yup

I must admit ... im at a loss :ouch:

Me as well. Im going to change fuel filter one more time to make sure I didn't pinch the o-ring and of thats not the problem im going to install a electronic pump in line to see If that will keep the prime

almost sounds like it could be a dying LP maybe ???

Im getting 25psi at idle

but if its to blame for the bleed back ... not good maybe the check valve should be in line between tank and the LP ?? :humm:.. might just work ... :c:

I would smoke test the fuel line that was just installed. Or pressurize the tank and entire fuel system and watch for leaks.

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that's what I was thinking but I don't know how bad it would restrict flow

Got a plan. Tommorrow going to put a new filter on if nothing going to try a lift pump inline. If still nothing ill be at a loss

Have you tried putting clear hose on the return side to see if there is air in the fuel system?

not yet. it runs perfectly fine it only does it on startup its hard starting.

I have good fuel pressure tight connections no leaks.

I noticed its harder to start the lower the fuel level is. starting to think fuel is draining back into tank. don't believe its the pick up tube because its brand new. OFV is new. all fuel lines are new.

losing my mind. going to try a new filter tomorrow.

what does it idle at?

800, but it always did

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I put my foot on it and it starts right up let it idle and almost every time I let me foot off after 10 secs of idling it sputtered for a second and idles fine and doesnt do it again until I shut it off

it sounds like air is getting introduced from somewhere

That is why I suggested to hook up a clear hose on the return line and verify for sure there is no air in the fuel system

now let me ask you guys a question. If I set up a fuel pressure gauge and I am getting 25 psi and it's solely drops after I shut the truck off is this a normal thing or should it stay pressurized

It may not bleed back off but the pressure will drop.

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Im leaning towards the check valve being bad in the lift pump

This thread has gone round and round when all that changed was a big line kit. Wouldn't that mean that the cause most likely be in the big line kit? If I was having this much trouble I'd find someone who knew what they were doing and let them fix the truck!

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Im leaning towards the check valve being bad in the lift pump

your silly, your building adiquite pressure. dont ya think if something like that was going onn you wouldnt have diddly for pressure. LOL cap and pressurize the lines and find the air leak.

Missing something somewhere in the mix here .....

Do you have or have you seen a fuel leak anywhere on your engine ?

No leaks anywhere

How did you plumb your big line kit? I don't think it's your check valve because you said once you shut your truck off then fire it up again it takes awhile to get it fired up. I can't see how fuel from your p pump to your lift pump drain back within few sec...and also pressure may seem good but what about flow? is it restricted? Lift pump might be shot. Or you got air in the system. Hope this make sense

This is such a mess. Pressurize the tank or use a smoke machine. If not leaks on suction side outside of tank then most likely the pickup is cracked. What about the elbow at the fuel pump is it good?

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The pick up is brand new. And yes the elbow is good.

Even new pars have faults occasionally.... Just sayin ...

ya but its been veiwed a million times. its nearly viral. LOL

take the sending unit out of the tank. keep ALL the lines connected. cap the line at the pick-up to lift pump connection and put a few PSI of compressed air to it. this is where you will get air into the system that will F$$$ with you. (the suction side of the system.) you will see no visable signs of a leak while operating the truck. all other sections of fuel line will pysically leak fuel because they are under some kind of pressure. if you have no leak after the test. take your injection pump off because something is going on.

fuel and air is all a diesel needs. if your getting air to the cylinders and unmolested fuel to the pump than its the fuel delivery piece by default.

Good call :tu:

I've actually seen guys chase something like this and it end up being the shutoff solenoid binding after they've worked around it.

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or a faulty shutoff solenoid relay

Well after a long battle, found out what happened.

First I figured I would change the fuel filter one more time to be sure, still the same issue.

Dropped the tank, checked the draw straw and gaskets/ return lines etc around the tank. Still having an issue.

Checked all the lines to make sure they were all tight, which they all were. Checked all the fittings in and out. Still having an issue.

Double checked ofv and all my DV and injectors, all tight.

I had already installed a check valve on the return line.

After a bunch of f bombs and mental breakdowns I figured screw it.

Found an old Holley pump laying in my garage and figured hey why not try to plumb this up. Got all the fittings and things I would need.

Hooked it up today,wired it into a key on circuit.
bam, fires right up without hesitation.

Im guessing that the mechanical lift pump didn't have the sack to fire over with the big lines connected, but either way now its like a dream.

Yes both pumps are hooked up.

I would like to thank all of you for your help through this.

yeah dual feeds are nice ... when i get to that point it will happen too .. so ..

lift pump feeding IP, electric pump feeding IP, check valve allowing flo to IP from both LP, and elec pump ... so they dont over push one another that way ..... this is my understanding anyways ..

Exactly and its only a 13 or 14 psi pump so it doesnt pump through the mechanical one

Good deal... Glad all is well in the universe now !!! LOL ... ��

Lol runs like a beaut now. Even better when I put tranny fluid in up to the range

I had issues with my stock lift pump doing the same thing and it was all stock then one day at -30 wouldn't start so I put a elec pup in to get it into shop after that I disconnected the lift pump and run a elec lift pump this was the 3rd and final lift pump

things I like about the elec lit pump when i change filters I open the bleeder and turn key on no more pumping by hand

and it starts so much better

glad you have it fixed

yeah its nice to have the dual feed ... if the electric dies .. the LP will get ya home in a pinch ... hence the check valves after both pumps