Gas fumes in cab after pulling up or in heavy traffic

Mine was covered with dry mud and all the lines were buried. They seemed OK but that's were I'll start.

I don't have a body lift so trying to get a glimpse of what's on top of the tank without dropping it is nearly impossible. I wish I had a snake cam.
 
mine has a 4' Body Lift and it makes it so simple to see in there, can you use your phone camera to record and look for soap Bubbles ? they sometimes bubble up 2 or 3 inches and are quit noticeable.
Mine was covered with dry mud and all the lines were buried. They seemed OK but that's were I'll start.

I don't have a body lift so trying to get a glimpse of what's on top of the tank without dropping it is nearly impossible. I wish I had a snake cam.
 
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No probable cause yet but I looked at the tank without dropping it and see stains when gas leaked from the top and blew back and down the sides while driving. There's no way to get a camera up to the top without lowering the tank.
 
@jpjeep26uk Any luck?

I pumped out the fuel tank yesterday and started loosening the bolts to drop the tank. I still think it's strange that after several years of no smell that this came about in one day but with the tell tale signs of fuel leaking from above it should be obvious once I drop it down.

I'm also going to cut the access panel above the fuel pump ONCE I GET THE TANK REMOVED and far away from any sparks. I hate to cut up a good piece of of the body but someone would hale to give a good reason not to do it.
 
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Ok I may have located the problem. As I was lowering the gas tank I found the right side vent hose had become disconnected with signs of fuel spilling out on top of the tank.

Several reasons come to mind, first being the gas tank was full when I parked it and possibly pressure in the lines seeped by and popped off the line. There are no hose clamps on the vent lines like there on the fuel pump supply and return lines. A second thought comes to mind is when I had the tank out two years ago I cut the tube for the 15 to 20 gallon capacity mod and this brings the fuel level much closer to, or right at, the top of the tank..

One side note about that 15-20 gallon mod is every time I fill the tank it overflows while filling where it never happened before and I'm not pleased about that. I like the extra mileage but not spilling a cup of gas on the ground. I never read that part in the reviews.

The vent check valves and grommets look ok but the hoses look old and one was pinched between the tank and floor brace above it. Even though the vent vales look good I have new parts on order and will pick up new hoses too, maybe add small pinch clamps.

As for the 15-20 mod I think I still have the piece of tube I cut off which is about 2/3 of the original length. Doesn't everyone save all their old junk?
If I can't find it I'll just jam a short length of 1/2' copper tube in and call it a day. Yes it does fit. That should give the tank a little more breathing room inside.

Cheers.

1.jpg
 
As for pressure testing the tank, once I had it out I reconnected the filler neck hoses and plumbed a tube onto the vent T fitting. Giving it a quick shot of 3 PSI air it it held pressure for several minutes until I removed the gas cap.

I found only one slight seep with soapy water where the vent hose connected to the left side vent and around that rubber grommet. A hose clamp might have stopped the hose leak.

Thanks for the help with this!

2.jpg
 
As for pressure testing the tank, once I had it out I reconnected the filler neck hoses and plumbed a tube onto the vent T fitting. Giving it a quick shot of 3 PSI air it it held pressure for several minutes until I removed the gas cap.

I found only one slight seep with soapy water where the vent hose connected to the left side vent and around that rubber grommet. A hose clamp might have stopped the hose leak.

Thanks for the help with this!

View attachment 121732
That’s the cleanest underside of an old Jeep that I have ever seen.
 
That’s the cleanest underside of an old Jeep that I have ever seen.
The only rust I've found was the drivers floor pan which I've replaced when the engine and transmission were out. I also pressure washed underneath and painted it then cheap undercoating.
 
Ok I may have located the problem. As I was lowering the gas tank I found the right side vent hose had become disconnected with signs of fuel spilling out on top of the tank.

Several reasons come to mind, first being the gas tank was full when I parked it and possibly pressure in the lines seeped by and popped off the line. There are no hose clamps on the vent lines like there on the fuel pump supply and return lines. A second thought comes to mind is when I had the tank out two years ago I cut the tube for the 15 to 20 gallon capacity mod and this brings the fuel level much closer to, or right at, the top of the tank..

One side note about that 15-20 gallon mod is every time I fill the tank it overflows while filling where it never happened before and I'm not pleased about that. I like the extra mileage but not spilling a cup of gas on the ground. I never read that part in the reviews.

The vent check valves and grommets look ok but the hoses look old and one was pinched between the tank and floor brace above it. Even though the vent vales look good I have new parts on order and will pick up new hoses too, maybe add small pinch clamps.

As for the 15-20 mod I think I still have the piece of tube I cut off which is about 2/3 of the original length. Doesn't everyone save all their old junk?
If I can't find it I'll just jam a short length of 1/2' copper tube in and call it a day. Yes it does fit. That should give the tank a little more breathing room inside.

Cheers.

View attachment 121731
I have a feeling there's a lot more of these Leaks out there than people might think !!!
 
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