XJ fuel venting issue solved

Hey all, I know I'm a NU-BE here, but just thought I'd share my experience with fuel a fuel venting issue. So awhile back I installed a larger gas tank ( 25gal vs 13gal) and I also installed new vent valves, seals, pump etc... After going out trail riding with the new tank, the engine stalled about an hour into the trip. Checked everything out and decided to pop open the gas cap. Fuel sprayed about 15 ft in the air! WTF! After this happened, I went and checked everything, well so I thought... Ended up being the "new vent valves"! At the time when I installed them, I had to go with Crown brand valves. Basically, the Crown valves had swelled and stuck closed, not allowing fuel vapors to escape to the charcoal canister. Yesterday I dropped the tank and swapped them out for Mopar ones, went trail riding and all is good! Hope this can help someone who may be going through the same issue!

XJs never came with a 13 gallon tank or a 25 gallon tank.

The stock vents usually don't plug, but I suppose it could happen Good job finding the issue.

Sorry for the typo (20 gal). But the after-market 20 gal tanks hold close to 25, I measured it. The Cherokees were available with two otional tanks in 1987 (may be other years also) , mine had the smaller one with the vent tube bent downwards, reducing capacity. The larger tanks had a straight vent tube. And if you shop around for gas tanks, you will find both options are available. Some tend to do the tank mod by cutting the vent tube and rotating it 180 degree's, to gain more capacity. Just trying to pass on useful info....

WB9YZU said:

XJs never came with a 13 gallon tank or a 25 gallon tank.

The stock vents usually don't plug, but I suppose it could happen Good job finding the issue.

Click to expand...

You might want to relook into that. At least the 13 gal part. Both my 89's had the 13 gallon tanks. I got the 20 gallon tanks that where an option from the parts store and they do tend to fill up more then 20 gallons if you fill them ALL the way to the fill hoses. That may be where he got his 25 gallon number from. But the 13 gallon tank was standard on most older XJ's and the 20 gallon tank was optional on the older ones.

Owned a 85' and a 86'. I could have sworn they were 15 gal capacity. I used to fill the filler hose, so maybe that's where I got that figure

No Matter; I did a search on 1986 Jeep Cherokee Fuel Tank.

Results were 13.5 gal and 20 gal up to 91'

The moral of the story of this thread appears to be two fold:

Memory is faulty among old folks
If your gas tank spews fuel when you open the cap you may just want to check the tank vents.

Thanks everyone! Thought I was loosing my mind there! :looney:

The really interesting part is that the "13 gallon" tanks and the "20 gallon" tanks are the same physical size. I have never understood why AMC (originally) artificially limited the fill to 13 gallons unless it was a marketing ploy. My '85 had the 20 gallon tank -- wow!

Go-Jeep has an article on modifying the tanks to increase the fill capacity:

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

Not that it really matters all that much, but just for clarification, Crown DOES NOT sell those, so you must have bought another brand. I don't know if Omix does, but searching online I only see Mopar as producing these.

This was copied from Team Cherokees web site about the vent valves .... I know Crown doesn't show a listing for them, but that's how they arrived! Crown label and part number. Now I wished I saved the packaging! Didn't realize it would cause such a ruckus ....

Featured Item: Fuel Tank Vent Valve & Grommet Set OEM GW 1980-1991
This Is A Set Of Direct Replacement OE Style Fuel Tank Vent Valves With Direct Replacement Vent Valve Grommets. Each Gasoline Tank Has 2-Vent Valves With Grommets On The Tank. These OE Fuel Tank Vent Valves Are Located At The Top Of Each Side Of The Fuel Tank & Helps Prevent The Fuel Tank From Buckling Inwards & Vapor Locking Causing Your Fuel Tank To Constrict & Not Allow You To Fill Up The Gas Tank All The Way Up Or Take Forever At The Gas Pump To Add Gasoline. If Your Fuel Tank Is Not Ventilated Properly-The Gasoline At The Pump Will Be Very Hard To Add & If These Fuel Vent Valves Are Clogged Or Dirty-These Will Cause This Problem. These Vent Valves Will Also Cause Higher HC Emission Levels If They Are Dirty Which Will Cause Gasoline Fumes To Enter Inside Your Jeep On Very Hot Days.The Rubber Grommets Tend To Dry Up & Crack Over Time Causing Either A Small Gasoline Leak Or Can Become Quite A Large Evaporation Leak Making Fumes Come Inside Your Full Size Jeep As Well. These Gas Tanks Commonly Will Buckle Inwards In Very Hot Climate Areas If These Vents Are Not Kept Up & Regularly Replaced. Also Check Your Fuel Filler & Vent Hoses As The Vent Hose Also Helps Aide In Venting The Fuel Tank. Overfilling The Fuel Tank Will Contribute To Getting These Vent Valves Prematurely Dirty & Making Them Require More Frequent Changes. We Recommend These Be Changed At Minimum Every 90,000 Miles In Normal Temperature Areas But More Often In Warmer Climates As Needed. This Part Would Be Considered The PCV Of Your Gas Tank & Treated Like A Filter That Requires Maintenance. These Direct Fit OE Style Fuel Tank Vent Valves With The Grommets To Keep Them Tightly Installed & Air Tight Will Fit All Jeep Grand Wagoneers & Full Size Wagoneers & Full Size Cherokees From 1980-1991 ONLY. WE ARE SELLING THESE DIRECT REPLACEMENT OE STYLE FUEL TANK VENT VALVES TOGETHER THE GROMMETS AT THE SAME TIME. YOU CAN PURCHASE 1-VENT & GROMMET SET OR 2-VENT & GROMMET SETS TO MAKE SURE YOUR FUEL TANK IS VENTILATING AS IT SHOULD. SAVE MONEY BY PURCHASING THESE VENT VALVES WITH THE GROMMETS VERSUS GETTING THE GROMMETS SEPARATELY & A BUNDLE OVER THE OE GROMMETS. IN FACT--THE DEALER LIST PRICE ON THESE PARTS WOULD SELL AT MORE THAN DOUBLE THE PRICE OF WHAT WE ARE SELLING THESE SAME QUALITY VALVES & GROMMETS FOR WITH THE SAME 12-MONTH WARRANTY. WE HAD THESE SPECIFICALLY MADE SO THAT WE COULD SAVE OUR CUSTOMERS MONEY. GROMMET PART#52018823 VENT VALVE#J5360058

Featured Price: $11.95

Quantity :

No problem or ruckus, they most likely were Crown seals, but definitely not the valves. They (TeamCherokee) probably combine them to make the kit in house and just combine suppliers.

I wish Crown had them as I needed them before when I installed the XJ tank to my J20.