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.