Help diagnosing possible fueling issue SOLVED

Sidewinded_idi

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Problem solved. It’s sucking my new line flat. I checked it while running and in the loop even at idle it’s about half round. Rev it up and it goes almost flat. I used injection line so I’ll have to locate something stiffer
 

towcat

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Problem solved. It’s sucking my new line flat. I checked it while running and in the loop even at idle it’s about half round. Rev it up and it goes almost flat. I used injection line so I’ll have to locate something stiffer
you might have blocakage upstream too. if the showerheads are gone, FSV might have stuff blocking it internally.
 

franklin2

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Problem solved. It’s sucking my new line flat. I checked it while running and in the loop even at idle it’s about half round. Rev it up and it goes almost flat. I used injection line so I’ll have to locate something stiffer

I have been having a problem with that lately when I go to the parts store. It seems when they make the hose they wind it so tight on the roll that it's oval instead of round. You can't buy anything these days without something being wrong with it.
 

Sidewinded_idi

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Yes thanks guys, when I did the lift pump I removed both gas caps and blew back the lines. Both felt clear but I do need to drop the tanks and redo the shower heads. The line had a loop the problem was I used fuel line, it’s tough but still soft and I noticed today after removing it when ou do the loop it’s so soft it collapses in on itself. I went and picked up 3/8 fuel injection line and it’s hard as a rock. Made the new loop and going to drive it now. With the other new line I held it at idle and it was pulsing open/shut with the cam lobe. Rev it up by hand and it went almost flat. This new stuff is hard like the stock line so should be ok now
 

Macrobb

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Yes thanks guys, when I did the lift pump I removed both gas caps and blew back the lines. Both felt clear but I do need to drop the tanks and redo the shower heads. The line had a loop the problem was I used fuel line, it’s tough but still soft and I noticed today after removing it when ou do the loop it’s so soft it collapses in on itself. I went and picked up 3/8 fuel injection line and it’s hard as a rock. Made the new loop and going to drive it now. With the other new line I held it at idle and it was pulsing open/shut with the cam lobe. Rev it up by hand and it went almost flat. This new stuff is hard like the stock line so should be ok now
I still think you have a problem. On flat ground, fuel should siphon out out of the line from the tank, no pump required. So if your pump is drawing enough of a vacuum(against the tank) to crush even weak fuel line... you have a blockage somewhere.
 

Sidewinded_idi

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I still think you have a problem. On flat ground, fuel should siphon out out of the line from the tank, no pump required. So if your pump is drawing enough of a vacuum(against the tank) to crush even weak fuel line... you have a blockage somewhere.
Idk about that one, the lift pump is going to pull a vacuume regardless of blockage or not. A soft line especially warmed up has no chance of staying open. Ever seen a lower radiator hose with no spring? It’ll suck shut at high rpm, doesn’t mean it’s backed up
 

Thewespaul

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Idk about that one, the lift pump is going to pull a vacuume regardless of blockage or not. A soft line especially warmed up has no chance of staying open. Ever seen a lower radiator hose with no spring? It’ll suck shut at high rpm, doesn’t mean it’s backed up
Well when you pull that line off the lift pump it should be like a faucet of fuel since that is the lowest point in the fuel system. I would at least try to blow some air back to the tank
 

Sidewinded_idi

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Well when you pull that line off the lift pump it should be like a faucet of fuel since that is the lowest point in the fuel system. I would at least try to blow some air back to the tank

Yes I posted earlier that I did blow both lines back when I did the lift pump
 

frankenwrench

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Fuel tank vent.

Might be worth checking out.
Mine was blocked after my rebuild and so was fuel cap. Would run a bit loose power fall on its face and then die. Took the fuel cap off and ran great so I knew then I had some blocked vent and/or cap so just replaced cap and removed vent and ran a pipe cleaner through it. Replaced the hose on vent cause it looked pretty rough anyway. Made filling up faster too without the spray back leaving me greasy to go to a wedding in. Lol
 

gfemling

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Problem solved. It’s sucking my new line flat. I checked it while running and in the loop even at idle it’s about half round. Rev it up and it goes almost flat. I used injection line so I’ll have to locate something stiffer
I last time I replaced the mech lift pump I noticed the hose, even new hose, tended to collapse in the loop. I found a spring with an OD slightly less than the 3/8” hose ID- think was a “spring door” spring. Stretched the spring coils out a little so it will configure around a small loop better than as originally wound. Then thru trial & error figured correct length to shorten spring to and pulled it thru hose so about an inch shorter than hose run to allow room to slip over pipes where clamped. Found a 5/16” UNC thread fit nicely into end of spring which allowed “grabbing” end of spring with a short “pulling mandrel” to attach a wire to pull thru hose- just thread spring onto it a thread or so as longer attachment makes unthreading inside hose more difficult. This inner spring won’t allow hose to collapse, won’t rust due to diesel and doesn’t significantly reduce flow. Had considered an external coil similar to those on hydraulic lines of heavy equipment but couldn’t find small coil and stumbled on this idea- works well for me ;-) Just an idea to consider.
 

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