Fuel tank filler tube mod to convert 15 gallon tank to 19 gallon

TJ4Jim said:
The 15 and 19 gallon tanks and accessories are exactly the same size and dimensions,the only difference is the length of the blow molded vent tube that extends into the tank, otherwise Everything is the same including the filler tube.
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An earlier poster on this thread provided photos (of a 15 gal & 19 gal) that showed BOTH the filler tube and vent tube are longer in a 15-gallon when compared to a 19-gallon tank (realizing that both tanks are identical with different part #s). So the question is, will shortening the vent tube to about 1 inch in length and keeping the filler tube the same length work out? If so, what considerations (safety or otherwise) should be taken into consideration?
 
BlueDemon98 said:
As part of the 15 to 19 mod, does it matter if the longer fuel filler tube in the 15-gallon remains the same length? I'm assuming only the vent tube needs to be trimmed down. Thanks for the great comparison.
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I only trimmed the vent tube. I don't think you want to mess with the filler tube.
 
BlueDemon98 said:
Did you replace the pump, and if so, did you install a 19-gallon fuel pump? If that is the case, how is the gauge behaving after the mod? Thanks
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I know you didn't ask me, but FWIW I did not replace the pump, and now my gauge just stays at full for the first four gallons, and then behaves like normal.
 
BlueDemon98 said:
As part of the 15 to 19 mod, does it matter if the longer fuel filler tube in the 15-gallon remains the same length? I'm assuming only the vent tube needs to be trimmed down. Thanks for the great comparison.
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Yes, only the vent tube needs to be trimmed down. The longer fuel filler tube remaining the same length makes no difference. It is now well over four years since I made this modification. Everything is working fine. I can get well over 15 gallons in the tank (I never let it run out of gas to see exactly how many gallons). Also, the sending unit on the (then) new Delphi fuel pump makes the gauge on the dash read correctly, as far as when the tank is full, etc.
 
BlueDemon98 said:
As part of the 15 to 19 mod, does it matter if the longer fuel filler tube in the 15-gallon remains the same length? I'm assuming only the vent tube needs to be trimmed down. Thanks for the great comparison.
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Only the vent is modified, filler is untouched.
 
TJ4Jim said:
It behaves no different from any 4.0 jeep since the pump and tank are now the same.
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TJ4Jim said:
It behaves no different from any 4.0 jeep since the pump and tank are now the same.
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Thanks. All re-assembled with the hardest step being getting the locking ring to thread/sit properly. With the mod, marks full with about 18.5 gals in it, and the rail fuel pressure is at 54 psi. Cranks right up and will see how things work out with the Delphi FG1353 hoping I don't have to do this again for a while.
 
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BlueDemon98 said:
An earlier poster on this thread provided photos (of a 15 gal & 19 gal) that showed BOTH the filler tube and vent tube are longer in a 15-gallon when compared to a 19-gallon tank (realizing that both tanks are identical with different part #s). So the question is, will shortening the vent tube to about 1 inch in length and keeping the filler tube the same length work out? If so, what considerations (safety or otherwise) should be taken into consideration?
Click to expand...

The filler tubes are identical on each tank, the vent tube needs to be trimmed a few inches so about an 1-1/2" or so remains as part of the tank. Filler has nothing to do with the amount of fuel it takes, it's the backpressure when the vent is covered that shuts off the fuel nozzle.
 
I just wondering why the extended vent tube to begin with. I wonder if there is a safety concern no one is thinking about.
 
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TonyArms said:
I just wondering why the extended vent tube to begin with. I wonder if there is a safety concern no one is thinking about.
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All very simple and nothing more than Jeep creating an option for the SE to upgrade to the 19 gallon tank. Cutting the extended tube is just matching the tube length in the 19 gallon version. Otherwise both tanks are identical...
 
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Just be sure it's not already a 19 gallon tank, only the most stripped down TJs came with a 15 gallon tank. The gas gauge is notorious for being overly pessimistic and saying you're almost empty when there's still 4-5 gallons remaining. Even when the Low Fuel light is on.
 
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