adamk

I was at Uwharrie last weekend when I started to notice a very heavy smell of gasoline. The Jeep was idling and the exhaust dumps under the cab so I didnt think anything of it at the time. As the day progressed, it could be smelt not only in the cab but outside the cab and by the vechicle following me on the trails. First step was to look for a leak. There is no heavy flow leak meaning there is no obvious place where liquid gas is spilling. I then opened the gas cap and there was enough pressure built up in the tank that it actually sent gas flying out of the filler neck. Later on in the day, I parked at our camp and just layed under the rear of the jeep and could hear gas(vapor not liquid) venting out of the tank due to the pressure inside the tank.

So this leads me to my question...

Is there a vent for the gas tank? If so, where is it? If not, what are common places to start searching for where this leak is coming from?

I'm sure if I really dove into the fuel system back there I could figure this out but I havent had much time lately.

CCKen

The fuel tank should be under pressure - 1-2 psi. The fuel filler cap should release the pressure if it gets higher than this.

You may have a leaking hose or seal at the Fuel Vapor Valve on top of the fuel tank, or the vent hose between the fuel filler neck and the fuel tank is deteriorated or loose.

If you can hear the vapor (pressure) leaking out when laying under the rear of the Jeep, you should consider one of the above as the problem.

adamk

Thank you sir. I'll check into those and report back

Firestorm500

Don't drive this bomb until you fix it.

Also, exhaust must exit out the back. You don't know you're getting carbon monoxide poisoning until the Coroner verifies Cause Of Death.

adamk

It's currently parked. It only seems to leak fumes while off road. I drove it 2 hours home from Uwharrie and then to and from work for 2 days with no notice of any gas smells.

Another note, when boucing around on the trail and then heading to the gas station right after, when I open the gas cap, you can hear the pressure release from the tank. When driving on road, I have never had that issue

CCKen

You might want to install a new gas cap as soon as you can. Make sure it is suitable for your year XJ.

adamk

I'm picking one up after I leave work today. That was already on the to-do list seeing how its still the original cap from '92

Kingfisher

Bad! Bad!

Like firestorm said,
You can't smell carbon monoxide!

adamk

I'm aware. Just been lazy and haven't reinstalled the muffler and new tail pipe since they were last ripped off.

adamk

So after work today I started to try and locate the leak. I did find that the vent hose that runs to the canister has a hole worn in it from rubbing the back of the valve cover. I will get that replaced and hopefully it will cure this issue. I will continue to monitor it and probably replace all the soft line and vents at the tank just for safe measure.

adamk

I've replaced that hose and will drive it the next few days to see how it goes

Seebradgo

Yo. Did you ever find the culprit? Curious because I've replaced my purge solenoid, canister, and gas cap. Still having issues with pressure build up when I crack open the gas cap. It doesn't spew gas out, but it feels like it's under A LOT of pressure.

BlueRidgeMark

You are responding to a thread that is 4 years old. That's rarely useful, and never cool. Ya done good by searching for the answer, but now, the best way to get help is to start a new thread.

Seebradgo

BlueRidgeMark

They are called zombie threads for a reason. 4 years is way past its shelf life. They rarely produce anything useful.

A better course of action is to post a new thread and ask the question, and possibly reference (link to) the old thread, mentioning any relevant info.

PMing the OP is a great idea - it doesn't clutter up the forum with dead threads that someone dragged out of the grave.