Gas fumes in cab after pulling up or in heavy traffic

jpjeep26uk

jpjeep26uk

YJ Enthusiast
Joined
Nov 12, 2022
Messages
195
Location
UK
Hi folks, On my eternal journey to thwart the petrol fumes in my cab after coming to a stop, I rechecked and replaced as best I could all my vacuum hoses and even took the Evap apart and filled with new charcoal and filters etc.
Then noticed by accident that when I lower my fuel flap, solid petrol smell right there!

So I've ordered a new petrol cap and was thinking of ordering those two hoses that go to the tank and an overfill hose?

So the questions are: could it be anything else thats causing gas smell to leak out the filler area? And is it hard to swap out the filler and vent hose? Do I need to drop the tank? Is it safe to do or should I get a mech to do it?

Anything else I might need to change or check for gas fumes in the cab after stopping or waiting at junctions?. My gas consumption does appear to have gone up in recent weeks, is this because its escaping out the filler area/ hole? Thanks all. 1988 2.5l TBT. UK owner.
 
jpjeep26uk said:
Hi folks, On my eternal journey to thwart the petrol fumes in my cab after coming to a stop, I rechecked and replaced as best I could all my vacuum hoses and even took the Evap apart and filled with new charcoal and filters etc.
Then noticed by accident that when I lower my fuel flap, solid petrol smell right there!

So I've ordered a new petrol cap and was thinking of ordering those two hoses that go to the tank and an overfill hose?

So the questions are: could it be anything else thats causing gas smell to leak out the filler area? And is it hard to swap out the filler and vent hose? Do I need to drop the tank? Is it safe to do or should I get a mech to do it?

Anything else I might need to change or check for gas fumes in the cab after stopping or waiting at junctions?. My gas consumption does appear to have gone up in recent weeks, is this because its escaping out the filler area/ hole? Thanks all. 1988 2.5l TBT. UK owner.
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Replacing hoses without dropping the tank may be possible but if it is it’s going to be a bear. If you haven’t seen any evidence of gas leaking on the ground I doubt that they need to be replaced.
 
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Also, have you checked to see if the vent line from the tank to the canister is clear? That is remove it from the canister and blow air into the tank.
 
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ytradio said:
Replacing hoses without dropping the tank may be possible but if it is it’s going to be a bear. If you haven’t seen any evidence of gas leaking on the ground I doubt that they need to be replaced.
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That's a good point- nope, no leaks at all.
 
ytradio said:
Also, have you checked to see if the vent line from the tank to the canister is clear? That is remove it from the canister and blow air into the tank.
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Haha, never even thought about that, I'll go do it now as it's early evening over here and finally the sun is out. I'll report back.
 
ytradio said:
Replacing hoses without dropping the tank may be possible but if it is it’s going to be a bear. If you haven’t seen any evidence of gas leaking on the ground I doubt that they need to be replaced.
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OK, had a really good look, took off the gas flap, filler nozzle guard and took off the underjeep plastic guard to look up and around. No leaks, no perishing rubber, no corroded metal nothing really. All checked out.
I did notice fumes around the filler area so I'm really thinking it's the cap not fittin any more. The rubber element has been broken and glued back onto the cap so maybe there'd a split or gap even when the cap is on.
 
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ytradio said:
Also, have you checked to see if the vent line from the tank to the canister is clear? That is remove it from the canister and blow air into the tank.
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OK I blew down the tube off the evap and even though it was hard as heck, my gf confirmed she could hear a hissing sound from under or around the rear left side of the tank..ish. So I'm hoping that's a good thing and the tube is working. I did notice it's quite perished, no visible holes but definitely cracks etc so I'll replace it at the weekend but it does seem to be transmitting air/ vapours to / from the tank. Thanks!
 
jpjeep26uk said:
OK I blew down the tube off the evap and even though it was hard as heck, my gf confirmed she could hear a hissing sound from under or around the rear left side of the tank..ish. So I'm hoping that's a good thing and the tube is working. I did notice it's quite perished, no visible holes but definitely cracks etc so I'll replace it at the weekend but it does seem to be transmitting air/ vapours to / from the tank. Thanks!
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That is also a big job that will require getting to the top of the tank by either dropping the tank or cutting an access hole in the rear deck.
 
Hi, sorry i meant the rubber tube from the evap is a little perished and then it goes down to a metal hose under the cab. I may replace the rubber hose bit.
 
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I intermittently notice a mild petrol (we call it “gasoline” 🤣) smell from my yj when slowing to a stop or in slow traffic , but I don’t smell it when it’s been parked, even in an enclosed garage.

I wonder if an exhaust leak upstream of the catalytic converter could be the cause.

How’s your exhaust manifold/pipes?
 
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Oh man, I've spent almost 12 hrs chasing the lines, replacing vacuum hoses, tightening every nut in sight. I found a totally broken rubber hose from the evap cann to the fuel tank and figured that MUST be it. Replaced the rubber hose and fitted my new very tight metal locking gas cap too. Nope. Nada. I had the roof off today on a rare British hot day and it was so noticeable. Fumes galore. Nothing smells around the tank or flap. I'm totally flummoxed as to where that gas smell is coming from! Grrrrr!
 
TRevs said:
I intermittently notice a mild petrol (we call it “gasoline” 🤣) smell from my yj when slowing to a stop or in slow traffic , but I don’t smell it when it’s been parked, even in an enclosed garage.

I wonder if an exhaust leak upstream of the catalytic converter could be the cause.

How’s your exhaust manifold/pipes?
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Good question, I'll have a closer look and see what's what. It does seem to be emanating from up front as I can't explain how anything from the rear could find it's way up front against the wind when I'm driving?
 
there are three seals or gaskets on top of the tank . I just replaced all three of mine to Pass California Smog check because my tank wouldn't hold 5 PSI pressure.
1). The Big square Gasket around the Fuel Pump access panel
2), 2 gromet style seals around the roll over check valves

To check your Gas tank's ability to hold pressure, have your Girl Friend do the following. attach a thin rudder glove to the fill tube with a rubber band.
Take a tire valve stem and cut off the large bulbus part on the end , this will leave you a straight valve stem with a Schrader valve inside . poke a small hole in one finger of the glove and insert the valve stem, secure it with a rubber band . use your air compressor to put enough air pressure into the tank to expand the glove like a balloon , Very little pressure is needed to expand the Glove Balloon and be carful not to blow off the glove from the fill tube. watch the glove to see if it stays inflated, if not refill the glove with air and spray the top of your tank with soapy water and look for soap bubbles at the leak . hope this Helps.
It doesn't sound like a hose or you would see drips on the ground, the seals I mentioned would emit air only. If you do this repair shake your roll over valves when you have them out, if they rattle they are in working order
 
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I got the Gasket for the Fuel pump access panel from O'Rileys Auto parts and the roll over valve gromets from either Quadratrec or Morris 4x4
 
Well heck. I've had my YJ for about two years now and kept it parked in the shop or garage and never smelled gas fumes until today. For several reasons I have not taken it out for about three weeks but within minutes of starting it today I smelled gas fumes from the back end area, not the exhaust.

I checked the engine area by the injectors and fuel rail just to be sure and it's clean, dry, and no gas smell. I did a short drive and even after sitting I could still smell the gas when parked outside with a slight breeze. Again from the back end. No dripping which is good, I think.

I did drop the tank about a year ago to fix a fuel sender issue and replace the filler and vent hoses. All looked good. I don't mind dropping the tank again but of course it's full so I'd rather burn off some to make it lighter. (figuratively) . I don't need any fires.

I'll follow this thread and try what's been suggested and report back. I'm just surprised that it came about so quickly when there was no smell before I parked it.
 
My Smog Tech told me he smelled gas at the rear of my TJ when he pressurized the Gas Tank and I should check the rear area for leaks. Another way to pressurize your tank is to use your Rubber Vent Hose. Disconnect your vent hose where it connects to the Steel tube that runs down the frame by the rear Drivers side Tire. There are three rubber Hoses that connect there from the Tank the two bigger hoses are the Supply and return, the smaller one is the vent hose and the one you want, Connect your afore mentioned customized Tire Valve Stem to the vent hose by means of hose adapters. you only need to interduce 4 or 5 lbs. of pressure into the tank ( don't go crazy here) more is not better. spray soapy water on the top of the tank and watch for bubbles. Doing it this way will also test your Gas Cap. after 3 or 4 minuets remove your gas cap and listen for a Hiss of pressure leaving the tank, if no Hiss is heard keep pressurizing and spraying soapy water and looking for the leak. When you interduce air pressure into your Gas Tank you can see it bulge like a balloon. Try this at you own Risk, I accept no responsibility for that one SILLY GOOSE out there......
 
when I dropped my tank to replace the fuel pump I was shocked by the condition of all the rubber lines on top of the tank. all three were cracked, brittle and ready to fail. None of them were leaking, but I'm not sure why.
That is where I would look.
 
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