Gas cap for 85 CJ7

[jfmcj7]

Hi everybody. I need some info. Does a 85 CJ7 needs a vented or non vented gas cap?

Recently I experience some issues with my CJ. Drove it up to the mountains last week and it kept on "stalling" out on me. The fist time I opened the gas cap and it was like a fire hydrant. It spit out gas about 6' out. The other times I opened the gas cap slowly and it was blowing out air for a good 15 to 20 seconds. The Jeep started right up after I "vented" the tank every time.

I filled up the tank before I left and drove about 30 miles before the first incident. Did that at least 8 times before it stopped when I reached 4000' elevation. After that it was fine up in the mountains.

The carbon canister was replaced about 2 years ago and so was the gas cap. I know the vent tube from the tank go up the the filler hose but I am not sure the gas cap is vented. All the caps I found say "non vented"

Any help will be appreciated.

Thanks

 

[hole]

IIRC , non-vented is what you're supposed to be running. Mine will occasionally give a quick whoosh of air when opening the cap, but thats it.

 

[Posi]

The fuel cap has a 2 -way relief valve for pressure and vacuum. If the pressure is above 1 psi and vacuum above 1" it should activate the relief valve. Outside those specs the relief valve is closed and may give some folks the impression the cap is non-venting. A slight whoosh of air when removing the cap could be normal if the psi and " are within specs. A louder or longer whoosh could indicate a need for a new cap.

I recently installed a new cap for the CO trail ride and filled my tank everyday without hearing a whoosh sound. The old cap's rubber seal was toast so plenty of venting there.

 

[jfmcj7]

Thanks.

I will start with a new gas cap. It always had a little whoosh sound when opening the cap, but this time it was a lot and the first time it spit out gas about 6' far. That is nor good.

 

[jzak]

I've been using this gas cap for the past few years. Seems to do the job. I had a similar problem driving to the beach in my CJ5 . It wasn't a geyser, but the engine started dying on me after a couple of hours. The tank was still half full, so I wasn't out of gas. After adding a couple gallons, the CJ it healed itself. I replaced the gas cap, and I haven't had the problem since.

https://www.amazon.com/dp/B000FQ0BSA/ref=cm_sw_em_r_mt_dp_U_2vDADb2C88TPD

 

[jfmcj7]

Thanks. Just got it today. Will head up the hill tomorrow. Jeep is still at our cabin up in the mountains. Will put the new one on and see how it does.

 

[jzak]

Thanks. Just got it today. Will head up the hill tomorrow. Jeep is still at our cabin up in the mountains. Will put the new one on and see how it does.

Good luck buddy! I think the problem I had was the old gas cap was such a tight fit that I couldn't turn it all the way to the locked position. Since it wasn't seated right maybe that created some backpressure in the system.

 

[Belizean]

I've been using this gas cap for the past few years. Seems to do the job. I had a similar problem driving to the beach in my CJ5 . It wasn't a geyser, but the engine started dying on me after a couple of hours. The tank was still half full, so I wasn't out of gas. After adding a couple gallons, the CJ it healed itself. I replaced the gas cap, and I haven't had the problem since.

https://www.amazon.com/dp/B000FQ0BSA/ref=cm_sw_em_r_mt_dp_U_2vDADb2C88TPD

Looks like original-still have mine on

 

[Lumpy Grits]

Do NOT buy OMIX-ADA.
Go to NAPA, they will have what you need.
LG