91 limited owner

Chrysler only holds the build sheet info for 20 years. So you better hurry if you what one from them. I got mine a couple of years ago.

Wonka1981

Interesting, I never knew there was an option for size of gas tank

F1Addict

I got the build sheet for my '89 in 2012 so if that's their policy, they're kind of lenient with it's enforcement.

Regarding the OPs gas tank size. This could be a combination of a bad sending unit for your gauge and a smaller 16 gallon fuel tank (which is actually a 20 gallon tank with a longer vent tube.)

Here's an awesome write-up on modifying the vent tube to increase the capacity of your tank with a few simple modifications. I mean if you're gonna go digging around in there to check the sending unit you might as well, right?

http://www.go.jeep-xj.info/HowtoFuelTank.htm

XJ?2010

My 2000 has done this ever sense i've owned it. I've ran the thing till the gauge says empty and it just keeps going i've never ran it out of fuel but when my gas light comes on i can get 13 gallons into the tank i've ran it down to being able to get 19 gallons in it so I think the floats are just jacked up in XJ's.

Basslicks

^^^ yup, I've done this too. Except for a while, my guage was broken so I actually DID run out of gas... but the light was on for like a week before it would run out.

Fsher21

The bottom of my tank has a few good dents near the edges. My light comes on 180 miles in, and I can only fit 12.5-13.5 gallons in every time. I'm so tempted to throw a gas can in the back and run the poor thing up to like 250 miles and see if i make it

My haynes does say standard fuel capacity is 13.5 gal. while the 20 gal is optional. Not sure how accurate that is, but i have receipts where I put just a drop over 13.5 in and didn't run with the light on more than 10 miles.

F1Addict

Virtually ALL XJs have a 20 gallon tank. My understanding is that the 16s are extremely rare... I've never even heard of a 13.5 gallon tank.

I've discovered that after the pump automatically shuts off, if I go really slowly I can get another 2-3 gallons in there which typically puts me at between 18 and 19 gallons... that's good enough for me.

Unknown XJ

My build sheet says I have a 20 gallon tank......but I've never gotten that much in it though.

trans_am7935

all cherokee's came with a 20.2 gallon tank from the factory, BUT, some were LIMITED by a were the fuel actually goes into the tank to only 16 or 13.5 gallons for some reason. you can check this by getting under the Jeep (it has to be cleen) and looking for a number stamped on the gas tank. it will state the size in gallons of the capacity of the tank. you can look up your vin to see if yours is limited or not.

there was a write up on here on how to remove the limitation, some guy in a YJ did it, and got his tank all the way up to 23 gallons or so.

F1Addict

Here's the tank mod...

http://www.go.jeep-xj.info/HowtoFuelTank.htm

trans_am7935

thats the one, thanks!

wildmustard

I just installed a vent tube 'extension' on my '93. Using this as a guide.

http://www.go.jeep-xj.info/HowtoFuelTank.htm

Rather than gluing something to the vent, I used 1/2" copper pipe and a 1.5" piece of 1/2" ID rubber heater hose with hose clamps. About 3" of copper pipe soldered to a 90 degree elbow. A bit of o-ring dressing to lube the rubber and slide it onto the vent tube. A perfect fit. The top of the vent tube is now about 1" below the top of the tank (actually, about 1/2" below the rib / allowance for the frame rails. Quite an array of socket extensions to get to the hose clamp inside the tank. I could just get my hand into the tank and needed every bit of reach that I could get.

I plan to run it at half a tank and then 3/4 for a couple of fills and watch for leaks on the pump and vent and filler necks. Then put the gas to her and see how much it holds. I will post an update in a week or two. I am in Canada 'eh, so volumes will be in liters. I wonder if the 16 gal. vs. 20 gal. discussions are a result of Imperial (as in Canada and UK) vs US measurements?

A couple of suggestions:
- I removed the tank, and can't imagine how to do this with the tank on the vehicle. Removal isn't that bad, and it went back together in under 2 hours. Plenty of room to work under there without jack stands, etc.
- before unscrewing the rings that hold the pump in place, blast it with some compressed air to get the gritty bits out of the way. It won't help with disassembly, but you don't want all that crap falling into your tank.
- clean the rubber seal ring. I have a tube of molykote o-ring dressing. It gave the ring enough tackiness to stay in place while everything else is fit into place.

Update: After a few days I poured the gas to XJ until 'click'. No force feed. Gas gauge is now beyond 'F'. Took a drive out to Lake Louise for a ski day in a dastardly snow storm. AWD for at least half of the trip. Refill at 3/4 of a tank in Canmore on the way back was 46 litres (about 12 US gallons, 10 imperial). About 280 km (175 miles). Definately have significantly extended range. 280 km in these conditions and AWD would probably have left me at a 1/4 tank. Maybe less. The return trip included idling at a standstill for about 45 minutes while a truck was pulled out of the ditch somewhere up ahead.

Firehawk068

Your fuel pump always draws from the crud at the bottom................That's why the sock is on there........

watertrucker

Probably just your gauge. My 96 XJ does the same thing. Drops quickly to 1/4 tank and then fills up with 10 gallons.

Basslicks

I've been noticing with my fuel tank that when I'm at the pump, I have to use the practice of "topping off the tank". I hate putting it like this because normally the people who top off are annoying because the pump clicks off every half a second and you can feel it while you're trying to pump your gas.

Normally, the pump will cut off at about 16-17 gallons. I listen for gurgling (which is essentially gas coming up the filler neck). Once the gurgling stops, I put light pressure on the pump lever to let the gas come out slowly until it clicks off again. I usually end of having to repeat this about 4 or 5 times, but I end up getting closer to that 20 gal capacity from very close to empy this way. I don't know if it's the design of the tank or what, but I could see how people are reporting only 16 gal capacity if this is what's happening.

My wife's Chry T&C van also has a 20 gallon capacity... but at the pump, that tank will tell you exactly how much gas you had left in that tank. I tried topping it off once and ended up with gas going down the side of the van. When the pump clicks off on it, it's done. Wish the XJ worked like that.