[romanella]

While looking online to add some mpg's to the Jeep, I found this. Just wondering what your thoughts are, if its legit, if you've done it, etc. This would be done on my DD, so I don't want to make the Jeep FUBAR. Thanks!

By John Duenes

Now that my 93 YJ is coming along since it was last seen putting on the **** Cepek 3 1/2" lift. I put some 33x12.50 15 Dunlop Mud Rovers and with the 2.5l 4cyl my gas mileage was down a bit. It was said that the YJ's all had 20-gallon tanks but they modified them to only hold 15 gallons. That was unless you paid for the 20-gallon option. After hearing the rumors and doing some investigation I decided to give this simple modification a shot. There is a plastic vent tube that runs from the fill vent hose down into the tank. All you have to do is pull out that plastic tube which is 9½" long and cut about 7" off. This procedure only took roughly 25 minutes start to finish. You don't need to drain the fuel but the less in the tank the better. Plus if you wait until it is almost empty it is a pretty cool feeling to fill up with over 19 gallons.

1. First remove the negative terminal from the battery. This may sound menial but you are working near the taillights and don't want any sparks from some lose connection.
2. Remove the gas cap to release the pressure from the fuel system. Let it set for a few minutes to let the fumes dissipate.
3. Remove the filler neck shroud that is below the gas filler housing on the underside of the body. This is held in place by 4 push clips. To remove these, pry the head away from the body then after the head pulls away remove the whole clip. If your Jeep is like mine they were brittle so just yank away then head to your favorite parts store and get new ones.
4. Using a Torx bit, remove the license plate (watch your fingers) and the filler housing.
5. Looking up from the underside you see the 2 hoses. The fill vent hose is the upper one running to the rear connection in the fuel tank. The fuel filler hose connects at the front most location.
6. Remove both hoses from the fuel filler housing and set the housing aside.
7. The only hose you have to loosen and remove from the fuel tank is the fill vent hose. The one closest to the rear of the Jeep.
8. After removing the fill vent hose use your needle-nose pliers to remove the inner piece of plastic. You may need a thin screwdriver to make room for the pliers to grab the inner hose.
9. Pull the inner plastic hose out it will be just over 9 ½" long. All it needs to be is as long as the neck the fill vent hose connects to.

[Mark455SD]

http://www.4x4wire.com/jeep/tech/fuel/15to20gal/

[DownNDirty]

Yes I did this on the weekend added 5 gallons.
Here is the link with some pics.
http://www.jedi.com/obiwan/jeep/15to20gal.html

[romanella]

You're the man! Thanks Mark!!

[rustywrangler]

Very common mod

[70sElvis]

My suggestion is for everyone to check how much they currently hold before doing this mode. I was new to the jeep community and found this mode. I tore into the mode only to find out that one of the POs had already made it. Just a suggestion.

[1911pistola]

I did the mod love the extra 5 gallons

[sticksnstonesru]

Yes...more miles per tank....not per gallon.

[sebastian22]

this makes a huge difference specially on long road trips. i used to have to stop every couple hours. easiest mod ive ever done and the best part is that its free. if you use the right tools (extensions, swivel sockets, etc) you wont even need to lower your gas tank.

[NewhampshireYJ]

idc i get pretty good mileage.... 20$ will get me like 175miles

[trickle26]

I haven't done this mod but was looking at my 94 YJ factory build sheet and it says I have the 20 gallon tank.

NFAP - 20 gallon fuel tank

The weird thing is, I have only been able to fit roughly 14.5 gallons in my tank. Granted, I have never ran it completely empty but when my gauge gets right down to the 'red line' - 14.5 is the most I can get into the tank. It makes me think I don't actually have the 20 gallon.
Just wondering if any of you have checked your build sheets if it says 15 gallon or 20 gallon --- or if Jeep just listed 20 gallon on all build sheets because the actual tank is 20 gallons.

[shamrok911]

did it, love it, shoulda done it sooner.

[jay-h]

Note this does not affect all YJs.

[swedishdwarf]

Originally Posted by trickle26

I haven't done this mod but was looking at my 94 YJ factory build sheet and it says I have the 20 gallon tank.

NFAP - 20 gallon fuel tank

The weird thing is, I have only been able to fit roughly 14.5 gallons in my tank. Granted, I have never ran it completely empty but when my gauge gets right down to the 'red line' - 14.5 is the most I can get into the tank. It makes me think I don't actually have the 20 gallon.
Just wondering if any of you have checked your build sheets if it says 15 gallon or 20 gallon --- or if Jeep just listed 20 gallon on all build sheets because the actual tank is 20 gallons.

I don't know about the build sheet, but YJ gas gauges are notoriously inaccurate.

[sstaurus]

Originally Posted by jay-h

Note this does not affect all YJs.

Only 91+ as far as I know, 87-90 there were actually 2 different tanks.