Custom gas evaporator

[i30krab]

For the last 2 years on and off I kept smelling gas fumes under the hood and I couldn't find the cause. Recently I disconnected the gas charcoal canister altogether and capped the lines going back to the gas tank and the lines going to the emmission system. Surprisingly no code showed up on the consult but I did notice after emptying the tank and going to fill up at The pump,The pressure built up in the gas tank was tremendous!

So now I got some 3" pvc pipe and filled a 4 ft section with activated charcoal and connected the gas tank pressure release hose to this set up and added a exit hose and now I have no pressure build up and no more gas fumes under the hood coming into the cabin!

I still haven't figured out why the evaporator canister wasn't working and I also replaced it a year ago. Oh well, at least I fixed the problem. I guess I'll have to refill the canister with new charcoal on occasion.

Has anyone ever had this problem??

 

[oilyriser]

Neat!


There's supposed to be a back flush cycle, where fresh air is sent through the canister, drawing all the fumes to be burned in the engine. Maybe one of the valves that does this is broken, or maybe one of the pipes is blocked.

I wish gas stations were required to have this kind of setup, so they don't fumigate the neighbourhood every time they fill up their tanks.

 

[Gary Allan]

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I wish gas stations were required to have this kind of setup, so they don't fumigate the neighbourhood every time they fill up their tanks.

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I guess they abandoned original design for whatever reason. If you recall, the gas filler used to have 3 holes in it. Two were for the vapor recovery ..the round one for the fuel. They looked like a pair of fangs. The vapor holes weren't round ..curved oval, IIRC. I thought that they were just doing it in certain areas ..but I know that my 99 and 02 jeeps only have the fuel inlet hole.

It appears that they've come up with a better mousetrap for accomplishing the vapor recovery. It appears that they figured out that a coaxial single nozzle intruding into the filler neck would work just as well.

 

[Laminar Lou]

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Not sure if it is correct information, but I thought I recall that the new pumps allowed faster fillups and the higher flow meant lower overall vapors being released. I think the EPA & CARB only require an amount of vapor per gallon recovered and don't dictate how you have to do it.

 

[porcupine73]

Wow that's a neat DIY solution. Depends where you are; in Cali. and possibly other areas I believe all gas pumps recover the vapor.

 

[oilyriser]

I'm talking about the large underground storage tanks. Filling the tank on a car is only part of the problem. The same volume of gas fumes gets emitted when that gas is poured into the storage tanks at the gas station, and also when the tanker truck is filled up at the tank farm. I'm not sure how much vapor recovery goes on in these other stages. There's also probably some fumes lost when the tank farm tanks are filled. Even if they have a membrane covering the gas, a bit will leak through, and will have to escape as the level in the tank rises and the air is pushed out.

A 4' section of PVC is probably a bit overkill, but it'll work very well.