Fuel system
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Senior User
Joined: Jul 2015
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Fuel system
Hey guys got a fuel system problem from back tank. It will run fine off a jug but won't run off the tank. It's a brand new tank. And lift pump and injection pump. Any ideas? 1984 F250 idi
Methanoholic
Joined: Mar 2009
Posts: 6,442
Likes: 8
From: Maine (NorCal Native)
Will it run off a jug at the back? ie using the complete system except tank and pickup.
What shape was the pickup tubes in?
Do they reach the bottom of the tank?
How much fuel is in the tank?
-Enjoy
fh : )_~
What shape was the pickup tubes in?
Do they reach the bottom of the tank?
How much fuel is in the tank?
-Enjoy
fh : )_~
Tuned
Joined: Aug 2002
Posts: 476
Likes: 1
From: Greatest state on earth
This makes no sense. Either it was hooked up where the rear tank connects or at the lift pump. If you have 3 gal in tank or its hooked up to a fuel jug at lift pump???????
You need to confirm the fuel selector valve is getting voltage both directions when switched and then confirming the selector valve is actually switching tanks.
Then you need to confirm the lines are clean and pick up is below fuel level in tank.
If you have fuel in rear tank and truck runs off front tank, then flip the switch truck should keep running with a little hickup or one restart if fuel is being pulled from rear tank. If dies and will not restart then rear tank is not in the loop. Check fuel switch, fuel selector valve and blockage in fuel lines or pick up tube in tank.
Methanoholic
Joined: Mar 2009
Posts: 6,442
Likes: 8
From: Maine (NorCal Native)
-Enjoy
fh : )_~
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Methanoholic
Joined: Mar 2009
Posts: 6,442
Likes: 8
From: Maine (NorCal Native)
And my next question would be ... After more fuel has been added.
Do you have dual tanks and a FSV? (Fuel Selector Valve)
-Enjoy
fh : )_~
Do you have dual tanks and a FSV? (Fuel Selector Valve)
-Enjoy
fh : )_~
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Postmaster
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One easy way to test things... get a primer bulb. You can then use that for testing, running the output into a bucket. You'll see really quickly if you are only getting air(doesn't prime), is clogged(bulb stays "sucked in" and doesn't pull fuel, or is getting fuel just fine at a particular test spot.
BTW, I want to point out - On one of my trucks, I have the FSV, and it makes noise when you flip the tank switch. But while it pulls from the correct tank, it's returning to the front tank. Period.
So you could have a case with the opposite, I think? Where it only pulls from one tank, even if it "sounds" like it's working.
BTW, I want to point out - On one of my trucks, I have the FSV, and it makes noise when you flip the tank switch. But while it pulls from the correct tank, it's returning to the front tank. Period.
So you could have a case with the opposite, I think? Where it only pulls from one tank, even if it "sounds" like it's working.
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Senior User
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Well guys I hear the fsl working but I can't tell if it is the gauge goes from completely full to empty. Trying to get rear tank to work. Front is full of crudd. New ip, read tank, lift pump, oring kit, so the last thing I guess would be that wouldn't it...?
Methanoholic
Joined: Mar 2009
Posts: 6,442
Likes: 8
From: Maine (NorCal Native)
Take a piece of 5/16 and 3/8 tubing cut with a tubing cutter to roll the ends in a bit and use them to bypass the FSV without hacking off the Quick Disconnects.
Heck, Copper would work for temp ...
Be sure to deburr and polish so as not to tear up the seals.
-Enjoy
fh : )_~
Heck, Copper would work for temp ...
Be sure to deburr and polish so as not to tear up the seals.
-Enjoy
fh : )_~