gas fumes solution?

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brider

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My '66 Ford F250 has a gas tank right behind the seat with no charcoal canister lines, expansion tanks, or other such nonsense. When I fill it up, there are NO fumes in the cab, and only a little sloshes out the gas cap and down the quarter panel.

So why can't I drop my Pig tank, plug all my "accessory" venting lines, drill a small hole in the gas cap for venting, and call it a day and be DONE with the frickin' gas fumes?
 
There must be a problem somewhere if you're getting gas fumes all the time. I get NO fumes at all from my '55.
 
restore the emissions control canister plumbing to the way it was from the factory. Includes reconnecting hoses and replacing dry rotted hoses.

Way too many times PO's remove stuff without understanding what its effect will be, and end up with gas fumes. the trucks simply did not roll of the showroom floor smelling of gas. Cant imagine too many would have been sold.


there are 2 vapor recovery tanks in a '71 FJ55, and they are in the quarter panels. if they arent connected properly, there is a good chance they will vent fumes into the truck from behind the cargo area vinyl panels.
 
not being connected properly or being 30+ years old brittle/hard rubber. maybe replace all those lines??
 
I should note too that in my '55 when I did the engine swap I retained ALL the fuel tank venting and piping with the exception of the fuel return since that is not required with my engine choice.
 
Oh, I definitely rue the day I ripped out all the emissions stuff every time I fill it up, but it's all gone now, and I need to deal with it.

That's the point of my question: In my mind, given that this is NOT a "green" vehicle at all, if I go to the trouble of dropping the tank to replace all hoses, why can't I just duplicate the design of my '66 Ford and be done with all the plumbing and expansion tanks for good?

Here's the current condition:

Big tanks under the floor: Gone
Charcoal canister: Gone
Emissions "computer", speed marker, etc,: Gone

Remaining lines underneath the floor that used to run into the big tanks, or continue up to the firewall: I've T-ed them underneath the floor to (1) factory hard line that runs up to the firewall, and rubber-hosed this to a factory hose nipple on the underside of the air cleaner. I assumed the vapors would get sucked thru this line into the intake when the truck is running.

The fumes are bad when I fill it, and eminate from the driver's side cargo panel area, although I can detect no liquid leaking. The cargo panels are not installed.
The fumes go away after 30-40 miles.

So yes, there must be a small leak in the expansion tank area or somewhere underneath when the tank is full. So when the tank is down, I'm trying to reason out why the Toyota design requires all this plumbing IN THE ABSENCE OF ALL THE EMISSIONS STUFF I'VE REMOVED, as opposed to a simple vented design like my '66 Ford.

I realize this has been beaten to death before. Just looking for a different spin than the "restore it to stock" approach.
 
Do you no longer have the thing in the cargo panel area that had all the hoses going to it? The idea of some of that stuff is to vent the tank regardless of the angle the vehicle is at. Even my '67 FJ45LV has a vent thingy in the rear cargo area though it was not connected when I got the truck.
 
WHOA! Never thought of that!

Of COURSE, those clever Japanese designers! If the truck's wheels on one side are in a downhill-side rut going down the entire 10,000 ft mountain in BFE, the tank still needs to breathe!

OK, so now I see how/why my '66 Ford gets away with it.

Yes, my expansion tanks in the cargo wells are still there, what were those things under the floor for?

Is a charcoal canister necessary, or is my current method (vent line plumbed into the carb intake) a viable alternative?
 
brider said:
Yes, my expansion tanks in the cargo wells are still there, what were those things under the floor for?

Is a charcoal canister necessary, or is my current method (vent line plumbed into the carb intake) a viable alternative?
Click to expand...

Are the expansion thingy in the cargo area still connected? Things under the floor??? I'm not sure what you mean there. All that is on my truck are 5 lines from the tank to the cargo area thingy, the fill hose and the feed line (the return is blocked off).

I should think that you could get away without the charcoal canister (I doubt it had one in '71 anyways).
 
Does your Ford run a return line?

My guess is no and that would be a significant difference betweent the two vehicles... Your Pig is returning warm gasoline to your tank.

I think people confuse emissions control equip w/ being green and mistakenly assume they can remove with no effect. The reality is that the engineers designed these systems to improve the driveability of the vehicle - in your case being able to drive the vehicle free of fumes...
 
capping off gas tank vents.....bad idea!

:wrench:X2 with Pablo; PO of my 74 pig had capped the 4 vent lines to the air fuel separator + the fuel return line capped with a live 30 Cal round:eek:leaving only the filler neck and the feed line to the carb; creating a very dangerous situation.........when fuel/air expanded it would force the fuel out the filler neck onto the area of the tailpipe:eek: .........no; the tank was not overfilled.......this was after burning off 4-5 gal! and it happened several times:eek: Toyota mechanical engineers are a lot smarter than I am and have had to undo most of the POs mods going back to originality to get it running safely and reliably!:steer:.................well thought out mods are great BUT personally prefer to have a nicely running platform if possible before upgrading........just my 0.02:cheers:
Lou
IMG_2168 fuel spillage.webp
 
fuel air separator and fumes

:wrench:in my 74 pig the gas tank vents its 4 corners to the fuel air separator # 45; from there via check valve # 40 goes to the charcoal canister in the engine bay........might consider hooking up the line downstream from the check valve # 40 to a universal type of charcoal canister behind the rear 1/4 panel to reduce fumes........I vented the canister up into the "D" pillar......driving about 200 miles a week no more gas spillage or raw gas fumes; the PO had removed the charcoal canister + lines to the airfuel separator and installed a 32/36 weber.........:hhmm:thought about it a lot but did not see any advantage going back to an original charcoal canister setup as the pig runs well with the weber so took the easy:hillbilly: way out and vented it this way...HTH

Lou
fuel separator.webp
 
Good info - I'm following this thread closely as my tank overflows out the neck after I fill and drive a bit (especially in hot weather) and I have some fumes in the cab. The fumes did decrease though when I retarted the timing...might be a separate issue though....hijack off. :cheers:
 
Guess what we have to dwell on is that the air in the gas tank will expand as the day warms up pushing the gas down and out through the path of least resistance which in my case was the filler neck.....IMO, those little vent hoses conected to the airfuel separator.....check valve......charcoal canister were very well thought out and crucial to the vehicles safe operation unless you use a vented gas cap..........HTH;

Lou
 
n2666s, thanks for the systems diagram posting. In that diagram, there is an image of what looks like a second air/fuel separator (as you call t, is that what it is?) with a broken line running to the UNDERSIDE of the charcoal canister. Is that the A/F separator on the pass side of the truck? Mine has an A/F separator on both sides.

Also, your diagram completely omits the giant tanks that were mounted to the underside of my truck, right under the rear seat floor. I wonder if these were an early feature, discontinued by the '74 model year?

Looks like I better suck it up and study the Specter parts page for my truck to see what I need to replace.
 
brider said:
In that diagram, there is an image of what looks like a second air/fuel separator (as you call t, is that what it is?) with a broken line running to the UNDERSIDE of the charcoal canister.
Click to expand...

Are you talking about the thing that's obscured by the "ih8mud.com" logo?? If so that's simply the gasket piece where the lines pass through from the cargo panel area to under the truck.
 
Those big tanks under the rear seat were last seen in '71...there were something similar in some of the 45s, I think, under the front seats.
I've never owned a '71, but I've seen those tanks. And i've seen the dual tanks in both your rear quarters. I never bothered to figure out how they worked.
I'm thinking that if you got a modern (say, '74ish) vapor separator, you could plumb it the same way in your '71.
I still have the charcoal canister and stock plastic vapor gizmo...no problem with fumes or anything.
 
Trollhole-

That link is PRICELESS! For anyone interested, the link Trollhole posted shows clearly the big tanks under the floor I was talking about.

I'll make a bookmark out of that Toyodiy site.

I'll also be posting a "wanted" ad for a charcoal canister.
 
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