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Charcoal canister substitutes?

bp71k5

bp71k5

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I just discovered my gas tank isn't vented and I need it to be. I have my old charcoal canister but it's too big to fit in the stock location. Are there any smaller canister from other vehicles or another option to capture the fumes and prevent my garage from stinking of gas fumes?
 
Charcoal canister. We don't need no stinkin charcoal canister.

Mine didn't have one when I got it. I'm about to pull those vent lines out when I put in the new fuel cell.
 
Got to be vented somehow now, or the truck would not run long.
If you do add a canister, say, from a junkyard, you will still need a purge valve setup to suck the fumes out from time to time into the engine.
 
Fordum said:
Got to be vented somehow now, or the truck would not run long.
If you do add a canister, say, from a junkyard, you will still need a purge valve setup to suck the fumes out from time to time into the engine.
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Once the tank builds up enough pressure, it blows out of the gas cap at very high pressure. :) I confirmed that no "purposeful" vents exists anymore. I have a feeling my engine running rich might be caused by pressure buildup in the tank and causing the fuel pressure to be too high. A vented gascap is an option as well, but I'd kinda like to do it "right".

I thought I've seen some bronze or stainless caps that are perforated with super small holes that allow air to escape but prevent liquids from entering?
 
Brian, you can still use your original charcoal cannister, it doesn't have to be mounted in the engine compartment. :deal:

You could mount it on the frame under the truck, in the rear near the fuel tank, basically anywhere it will fit then you just need to run the appropriate lines to it.
 
4X4HIGH said:
Brian, you can still use your original charcoal cannister, it doesn't have to be mounted in the engine compartment. :deal:

You could mount it on the frame under the truck, in the rear near the fuel tank, basically anywhere it will fit then you just need to run the appropriate lines to it.
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Yea, that though just occurred to me. Even the other side of the engine compartment might work. It's just that he hose fittings are cracked already so I'd have to replace the cap or fix it. I figured maybe one from a newer car might work just as good if it was smaller. Looks like a pick-n-pull run needs to be arranged.
 
bp71k5 said:
I thought I've seen some bronze or stainless caps that are perforated with super small holes that allow air to escape but prevent liquids from entering?
Click to expand...


Popoff valves, I just had this discussion with a friend today, that's what I would do. Right into the filler neck, up high.
 
I'd be careful as alot of the newer stuff will use an electric purge solenoid.
 
I've been running my TBI burb ever since I bought it with a gas tank that releases pressure when I open the gas cap, especially in hotter temperature days here in Phoenix, just have to be aware of it and open the cap slowly, which it also does say that on the cap too:whistle:

It's never seemed to cause any ill running effects, I don't think it's right, just never gotten around to finding out why it does that. Even passes emissions very easily when that time comes.
 
I just used a 5/16" fuel filter on the vent line, I don't know what it was out of but it had a 90 deg fitting on one end and straight on the other, I figure that should prevent water from falling into it.

I believe the vented gas cap only vents positive pressure, so you could end up with a vacuum in there too and go lean as the pump tries suck more fuel out.
 
folkenheath said:
I just used a 5/16" fuel filter on the vent line, I don't know what it was out of but it had a 90 deg fitting on one end and straight on the other, I figure that should prevent water from falling into it.

I believe the vented gas cap only vents positive pressure, so you could end up with a vacuum in there too and go lean as the pump tries suck more fuel out.
Click to expand...

I'm starting to wonder if a simple filter like that is maybe the simplest thing rather than trying to vent the fumes to the throttle body. My original canister is ok, but the vacuum diaphragm is ripped and so it doesn't actually evacuate any fumes. A new canister is $100 and I'm not willing to spend that much on it.
 
I just switched my truck over to that recently, but I have had my car with a filter like that for over 15 years, I never noticed any smell or anything. I'm expecting the truck to be the same, so far, no gas smell in the garage, it's been maybe 3 weeks. I suppose if you really want to, you could hook that hose inside the air cleaner, it's like a filter too. Just make sure it's the proper vent line, so it doesn't every push any fuel out there. I think the sending unit has a one way valve in that line or something, not 100% sure on that one, but that's what it looked like to me.
 
Well, cars ran for decades with nothing but a vented cap. I'm sure at least a few of them were in garages.
Usually its more important to let air in so you do not pull a vacuum when you use gas than to vent pressure.

Unless you are in Fl. like me, the tank does not usually build up enough pressure to do any damage.
 
Just to clarify, I don't know for sure this is a problem. I only know when I was in Moab last year, when the tank was running low, I could hear a loud hissing sound and a huge plume of gas fumes spewing passed the gas cap seal. When I stopped to check on it, I started to unscrew it and a huge rush of air started coming out so I put the cap back. Then I jammed a small stick under the rubber seal to let it vent. I could see the fumes rising out from the tank over the next hour or so. That's a lot of pressure build up.

My truck is nowhere near stock though. I used the old vapor line as a fuel pump return line and plugged the other tank vents temporarily when I go the fuel injection working. I just forgot to do anything about the plugged vents since it seemed to run ok, maybe a little rich.
 
bp71k5 said:
My truck is nowhere near stock though. I used the old vapor line as a fuel pump return line and plugged the other tank vents temporarily when I go the fuel injection working.
Click to expand...

If your sending unit is like my old one was, I am surprised that is even working. The old vent line actually went to a seperate can which was part of the sending unit, with a pin hole as a vent, and maybe a check valve in there, so you may not actually be returning much fuel at all.

The small 1/4" line was a return line. The new sending unit is the same way, except there is no seperate can, just some sort of a check valve it looks like in the vent line. And the TBI sending unit had a larger, longer return line all the way to the bottom of the tank.

You might want to drop your tank and take a look. I don't think your setup is correct trying to return fuel through the vent line.
 
I have a 71 so the sending unit is just a metal pipe with a mesh sock on the end. I plumbed a return tube into it which is just stainless tube. Pretty sure that part is fine.
 
Oh, OK, I see, that makes sense then, I thought you said you used the factory vent line for the return line. Nevermind then.
 
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