Charcoal / vapor / evap canister, how it should be set up and other information

[SirRobyn0]

I need to read through it when I get a few minutes. Been considering changing mine since it's 41 years old

I'd say it wouldn't be a bad idea. People sometimes think, or maybe I should rephrase, in repair industry before computerization the rule of thumb was the only time we'd replace a canister is if it was leaking vacuum, a pressure problem, or there was a fuel smell tending to be worse with more fuel in the tank(s) and no leaks were found on the fuel lines. If the charcoal in the canister becomes saturated fuel, either from the operator overfilling the tank constantly or from age then the canister won't store the vapors hence if it is a vented canister it might make a fuel smell, but if the canister is vented to the air cleaner housing, it'll never make a smell at least not when the vehicle is running.

All this basically to say that after 41 years I'd bet the canister is ineffective, but even keeping a ancient canister as long as it's not plugged or cracked, at least your fuel vent system is still mostly a closed system, though in theory if the canister is bad enough moisture could get in, at least there is the volume of the canister where moisture would probably drop out before getting to your tank.

All lot of words to say an old canister ever if worn out is likely better than no canister at all.

 

[RecklessWOT]

So you're not supposed to just remove it and vent the line? Crap I've been doing it wrong my whole life lol

Just busting balls man, good write up. Definitely nice to have detailed write ups om the site
(though no unfortunately none of my 20th century automobiles have a charcoal can)

 

[Ricko1966]

So you're not supposed to just remove it and vent the line? Crap I've been doing it wrong my whole life lol

Just busting balls man, good write up. Definitely nice to have detailed write ups om the site
(though no unfortunately none of my 20th century automobiles have a charcoal can)

You know the EPA is spying on us don't you?

 

[RecklessWOT]

You know the EPA is spying on us don't you?

I'm okay with that. I hope they tear up when they hear about all my exempt vehicles.

Not only is age a factor, but in NH nothing over a certain GVW is tested for emissions. So even the one truck I own that is new enough to need emissions (2008 2500hd) is exempt. The number of catless vehicles on this one property alone would make any EV owner whimper and cry lol.

 

[SirRobyn0]

So you're not supposed to just remove it and vent the line? Crap I've been doing it wrong my whole life lol

Just busting balls man, good write up. Definitely nice to have detailed write ups om the site
(though no unfortunately none of my 20th century automobiles have a charcoal can)

Thanks Kevin I appreciate that. Hey we all have different things we like and don't like and I can certainly respect that even if I don't agree.

 

[DoubleDingo]

Seeing that my truck needs to be complete to pass emissions, I'll opt to replace instead of remove until I can move to a place that doesn't test the older vehicles. I may replace the one on my '91 Cherokee, too.

 

[Rusty Nail]

Some of those canisters have replaceable filters in the bottom.
You'll have to unbolt it and look.

 

[1lejohn]

I just bought a new one for 70.00 . Rock Auto. I had to get one from a different year truck, the picture showed a 3 port. I also splurged , and bought a new gas cap.

 

[SirRobyn0]

I just bought a new one for 70.00 . Rock Auto. I had to get one from a different year truck, the picture showed a 3 port. I also splurged , and bought a new gas cap.

Yes, there are some canisters that are now unavailable but luckily they all work the same and can be with in reason adapted to work as long as you get a canister with enough ports. And even at that a 3 port can be adapted to operate like a 5 port but you'd need an outside vac control unit.

 

[Ricko1966]

Heck(see there within forum guidlines) you probably score some used good ones from @RecklessWOT hahaha haha wasn't sure how many hahas to put there.

 

[SirRobyn0]

Ok guys please forgive me I'm not trying to be difficult. While normally I'm all about side conversation, and side discussions, can we please just keep it to discussion about how the system works, part #'s, where we are able to source parts and such. Thanks.

 

[RecklessWOT]

Ok guys please forgive me I'm not trying to be difficult. While normally I'm all about side conversation, and side discussions, can we please just keep it to discussion about how the system works, part #'s, where we are able to source parts and such. Thanks.

Heck(see there within forum guidlines) you probably score some used good ones from @RecklessWOT hahaha haha wasn't sure how many hahas to put there.

In all seriousness I just may have some laying around. I typically don't throw much away "just in case I ever need it one day". I know for a fact I still have the one from my 87 'burb (just had my hands on it like a week ago when I was digging through a bin of parts) but I'm not sure if it's good for anyone here as my truck originally had the high altitude emissions package, I would have to assume the canister is different, there was an extra vent and from the gas tank. But I can look at it, and can try to sort through my other junk. I have at least a couple from some 80s j@p cars, and probably still one or two from old jeeps, and possibly a normal one from the '87 longbed I used to have with federal emissions. I think the one from the T/A is long gone, but I could take a look for that too, I honestly have no idea what is piled up inside that basket case. I've never seen the back seat in my own car because it's piled so damn high with stuff from at least two cars that came with it

 

[DoubleDingo]

I looked up my application and it shows a filter, not a new canister.

 

[SquareRoot]

I converted my 85 from carb to aftermarket EFI. It was very simple and effective to use a 3 port cannister and only having the 3 lines to deal with. I had pulled it off a 89 burb in the junkyard. I'm thinking that the TBI era had 3 port cannisters as there were no fuel bowls associated with carbs anymore. However, I'm assuming more ports came back into play later on when the ECU started integrating with their control functions?

I also have read that if liquid fuel ever gets inside a cannister it will ruin it. Drying it out will not restore it. Something about gasoline turning the charcoal or (?) to gel. Don't know if it's a fact, just passing on what I read. I do know for a fact that gasoline can get into the cannister for different reasons. Probably most commonly is a non-vented gas tank and overfilled gas tank that builds pressure and pushes it thru the vent line. That's all- I'm out. Kudos to @SirRobyn0.

 

[Bextreme04]

I converted my 85 from carb to aftermarket EFI. It was very simple and effective to use a 3 port cannister and only having the 3 lines to deal with. I had pulled it off a 89 burb in the junkyard. I'm thinking that the TBI era had 3 port cannisters as there were no fuel bowls associated with carbs anymore. However, I'm assuming more ports came back into play later on when the ECU started integrating with their control functions?

I also have read that if liquid fuel ever gets inside a cannister it will ruin it. Drying it out will not restore it. Something about gasoline turning the charcoal or (?) to gel. Don't know if it's a fact, just passing on what I read. I do know for a fact that gasoline can get into the cannister for different reasons. Probably most commonly is a non-vented gas tank and overfilled gas tank that builds pressure and pushes it thru the vent line. That's all- I'm out. Kudos to @SirRobyn0.

The new stuff is also 3 port. I just had to replace the one in my 2011 Suburban because it was clicking off the pump every time I tried to fill the tank. The new vehicles have an entirely sealed system with the canister mounted above the fuel tank right next to it in the back of the vehicle. One line goes straight to a vent port on top of the tank. Second line runs to a computer controlled "purge" solenoid mounted on the intake manifold, and the third port runs to a computer controlled "vent" solenoid bolted to the crossmember right above the rear axle. The vent solenoid then has a hose that runs all the way up to a filter that mounts to the top of the fuel tank fill point plastic. The caps are non-vented and the purge and vent solenoids are activated by the computer based on driving state and fuel tank pressure sensor readings.