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

Thank you so much, KC. I was led astray by the photos and videos of the modification for a YJ. From what I found today I thought it had to be done from the inside on a TJ. Thanks again. Jeff
 
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This is a mod I will be doing on my 02 tj sahara. I've only run it down to the "fill it soon" indicator twice. Went and filled up within 10 more miles. Both times I could only stuff in approximately 12gal. All info I can find says fill indicator comes on with approximately 3gal left. All info I can find on specs for 02 saharas say it comes with a 19gal tank. I'm confident I will find an extended vent pipe inside. I'm in the process of running my tank empty to drop it for my bumper install and will take care of the mod then.
 
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4 wheelin
I would check the part number on the tank. They are different. By 2002, I can’t imagine the part number is wrong. I can imagine an old tank slipped into production, but it will be clearly marked as such. Just below the frame on the drivers side on the side of the tank. See other posts for part numbers. I do think it is more likely a gauge issue by 02, but the part number will tell u. I am pretty sure the last 6 digits on the 15 gal are 8687AB.
 
JLANEF said:
4 wheelin
I would check the part number on the tank. They are different. By 2002, I can’t imagine the part number is wrong. I can imagine an old tank slipped into production, but it will be clearly marked as such. Just below the frame on the drivers side on the side of the tank. See other posts for part numbers. I do think it is more likely a gauge issue by 02, but the part number will tell u. I am pretty sure the last 6 digits on the 15 gal are 8687AB.
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I plan on checking the sn today but I have read quite a few different threads on this issue. Also a true 15gal tank would be visually smaller than a 19gal with an extended vent tube. As to the gauge/ sending unit issue, according to another thread that I read, the pump sending unit is the same for all three types of tank. Just for clarification, there is the old model true 15gal tank, and there is the 19gal in two styles, long vet tube and short vent tube. All three are the same depth. A true 15gal and a 19gal(long tube) will show the same action on the gauge. A true 19gal (short tube) will register full for about 60 miles longer before the needle starts to move. That is assuming approximately 20 mpg. I am confident that I will find a long tube in my tank. When I do this I will post pics.
 
Which is why I said a TRUE 15gal tank would be visually smaller. What we are really talking about here is whether a particular tj has a long vent tube or a short vent tube in its 19 gal capacity tank.
 
OK, So I don't know why ya'll think cutting the vent tube to give you 4 gals more capacity is safe. The ball tube is the cut off when full. The 19 gal tank has the shorter one in it. If you cut the vent tube, in my opinion you are asking for trouble in a roll over situation or a full tank sloshing around. I'm not sure why cutting the vent will allow you to put more gas in, but its purpose is to, well vent the tank. The balls purpose is to keep you from putting in more than your suppose to. I don't know if there is a glue that will hold up to gas, but that is the one that would need to be shorten and ball kept in place as well as the vent, which dumps back into the fill neck I believe.
IDK, but there is NO way I would cut the vent for more fuel capacity. Just my Opinion. Yea I know, we all got em :)
 
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oldtimer said:
OK, So I don't know why ya'll think cutting the vent tube to give you 4 gals more capacity is safe. The ball tube is the cut off when full. The 19 gal tank has the shorter one in it. If you cut the vent tube, in my opinion you are asking for trouble in a roll over situation or a full tank sloshing around. I'm not sure why cutting the vent will allow you to put more gas in, but its purpose is to, well vent the tank. The balls purpose is to keep you from putting in more than your suppose to. I don't know if there is a glue that will hold up to gas, but that is the one that would need to be shorten and ball kept in place as well as the vent, which dumps back into the fill neck I believe.
IDK, but there is NO way I would cut the vent for more fuel capacity. Just my Opinion. Yea I know, we all got em :)
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That vent is for venting the tank while filling only. It does not function to vent the tank once the filler cap is replaced.
 
oldtimer said:
OK, So I don't know why ya'll think cutting the vent tube to give you 4 gals more capacity is safe. The ball tube is the cut off when full. The 19 gal tank has the shorter one in it. If you cut the vent tube, in my opinion you are asking for trouble in a roll over situation or a full tank sloshing around. I'm not sure why cutting the vent will allow you to put more gas in, but its purpose is to, well vent the tank. The balls purpose is to keep you from putting in more than your suppose to. I don't know if there is a glue that will hold up to gas, but that is the one that would need to be shorten and ball kept in place as well as the vent, which dumps back into the fill neck I believe.
IDK, but there is NO way I would cut the vent for more fuel capacity. Just my Opinion. Yea I know, we all got em :)
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The tube is long on a 15 gallon tank and creates a trapped air space when the gas level reaches the tube end. The tank will not accept any more gas as the air now has no where to escape. The stock 19 gallon tank has a short vent tube direct from MOPAR which allows 4 more gallons to be put in the tank. That is the only difference between a stock 15 gallon and 19 gallon tank. It was MOPAR's way to get an extra $100 for the 19 gallon tank while not having to actually manufacture a different 19 gallon tank. The vent tube is shortened, (same as what has been proposed by the cut), by the factory. Also as stated, the vent tube actually vents into the filler tube, which is where the safety issues of a rollover and the ball are contained. There are pictures on the forum of the actual OEM 15 and 19 gallon tanks showing the short tube on the 19 gallon and how the tanks are identical in size, shape and everything. They only have a different part number stamped on the side.
 
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oldtimer said:
OK, So I don't know why ya'll think cutting the vent tube to give you 4 gals more capacity is safe. The ball tube is the cut off when full. The 19 gal tank has the shorter one in it. If you cut the vent tube, in my opinion you are asking for trouble in a roll over situation or a full tank sloshing around. I'm not sure why cutting the vent will allow you to put more gas in, but its purpose is to, well vent the tank. The balls purpose is to keep you from putting in more than your suppose to. I don't know if there is a glue that will hold up to gas, but that is the one that would need to be shorten and ball kept in place as well as the vent, which dumps back into the fill neck I believe.
IDK, but there is NO way I would cut the vent for more fuel capacity. Just my Opinion. Yea I know, we all got em :)
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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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Jerry Bransford said:
Not necessarily, the fuel gauge sender's accuracy is way too variable to assume anything about how much gas is left. I go mostly by my odometer and use the fuel gauge only as a rough estimate.

X2 to the above comments saying that the 15 gallon take is extremely rare. Most of those who think they have a 15 gallon tank are doing so due to the gauge being so inaccurate which is common. I thought the same thing on my TJ too when I first got it. Only the most stripped down models came with the 15 gallon tank, the rest of them came with a 19 gallon tank.

And even when the build sheet says 15 gallon tank, it will usually include the 19 gallon tank elsewhere in one of the upgrades like A/C or other upgrades. My '97 TJ's window sticker said 15 gallon tank which shocked me until I read further and found the upgrade to the 19 gallon tank mentioned inside a package further down the list items.
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Hey Jerry,
do you know where i can finde "further down the list items" for my jeep

Best greetings Lennart
 
DER52 said:
Questions about the fuel pumps in the two tanks have also arisen. As far as I know, they are identical except for the gas gauge float mechanism that tells the gas gauge that the tank is full at something under 15 gallons or something under 19 gallons. Those who have kept their 15-gallon fuel pump after making the modification to 19-gallon tank capacity report that it just shows full a lot longer.

The fuel pumps themselves are identical in size. I measured the height of my old 15-gallon fuel pump and the new Delphi FG1353 19-gallon one that I bought. The photo below is a bit misleading, because of the filter on the bottom of the new one and the electrical cord wrapped around the top of the new one, and the new one being a little closer to the camera, but they are the same height.

View attachment 97890

The close-up photo of the old one shows TJ15 on the gas gauge float mechanism.

View attachment 97887

A new Delphi 15-gallon fuel pump costs $60 more than a Delphi 19-gallon one from RockAuto. There is no need to buy the 15-gallon one.

The RockAuto website says that the Delphi fuel pumps are made in the U.S.A., but when you get it, the box says made in China. Yes, even Delphi now.

By the way, my old 15-gallon original equipment fuel pump was still working fine. I only replaced it because I had the tank off the Jeep and the Jeep has 157,000 miles on it.
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Hey DER52,
i am currently considering a new fuel pump. I think that i have the 15 gallon Tank. Are there any downsides to order the 19 Gallon fuel Pump.

Best greetings from Austria not Australia
 
LennartfromAustria said:
Hey Jerry,
do you know where i can finde "further down the list items" for my jeep

Best greetings Lennart
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I have a late build 1999 TJ and the build sheet says it is a 15 gallon tank. No 19 anywhere on the build sheet. But most importantly, the 15 and 19 have different part numbers and mine is clearly stamped, (part number is easy to see on the tank), a 15 gallon tank. I also agree with the writer that the gauge is very inaccurate At all levels. Especially under 1/4 tank. It can go to empty and past empty in less than10 miles, or just sitting turned off overnight!
 
JLANEF said:
The tube is long on a 15 gallon tank and creates a trapped air space when the gas level reaches the tube end. The tank will not accept any more gas as the air now has no where to escape. The stock 19 gallon tank has a short vent tube direct from MOPAR which allows 4 more gallons to be put in the tank. That is the only difference between a stock 15 gallon and 19 gallon tank. It was MOPAR's way to get an extra $100 for the 19 gallon tank while not having to actually manufacture a different 19 gallon tank. The vent tube is shortened, (same as what has been proposed by the cut), by the factory. Also as stated, the vent tube actually vents into the filler tube, which is where the safety issues of a rollover and the ball are contained. There are pictures on the forum of the actual OEM 15 and 19 gallon tanks showing the short tube on the 19 gallon and how the tanks are identical in size, shape and everything. They only have a different part number stamped on the side.
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Exactly correct. I have verified mine and a buddies exhaustingly.
 
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JLANEF said:
I have a late build 1999 TJ and the build sheet says it is a 15 gallon tank. No 19 anywhere on the build sheet. But most importantly, the 15 and 19 have different part numbers and mine is clearly stamped, (part number is easy to see on the tank), a 15 gallon tank. I also agree with the writer that the gauge is very inaccurate At all levels. Especially under 1/4 tank. It can go to empty and past empty in less than10 miles, or just sitting turned off overnight!
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Do you happen to know those part numbers? Thanks!
 
I found this on the net. I’ll go check mine to see if it matches.

The 19 gal tank has a part # 52018768
The 15 gal tank is # 52018687

1618707675732.jpeg
1618707734029.jpeg


the numbers above are correct. Mine is a 52018687 AB.
 
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