On warm days after driving to operating temperature the vapor canister smells like gas. Do they ever need to be replaced? I have checked the line connecting to the solenoid and found drops of gas in the hose. I am considering blocking off the hose, has anyone else had this problem? Thanks for your help.

 

When I saw your post, it caught my attention because I had a similar problem with my 1990 Pontiac Trans Am GTA. It has the 5.7 liter, turned port injected V8.

During the summer months, especially when I ran the air conditioning, I would actually get a raw gas smell coming into the passenger area, through the vents.

When it was checked, the vapor canister was actually full of gasoline . I had it replaced and it was fine for a while, then the smell came back. I had it checked again, and the dealership changed the canister and the rubber lines going to and from it.

Again, it was O.K. for a while, then the smell came back.

Right now, I'm on my fourth canister and things seem to be O.K.

I did finally find out from a dealership mechanic, who owns 2 GTA's himself, what the problem with the canister, is.

He told me that many of the canisters, made in the late 1980's and early 1990's, have a valve on top of the canister that is defective. It doesn't open and close properly and when it fails, it causes a vacuum effect, that sucks gas into the canister; like sucking a milk shake through a straw.

He told me that you may have to buy several canisters, in a row, before you find one with a valve, that works right.

I don't think you can replace "just the valve", you have to buy the whole canister.

I am curious about one thing: Did you have the gas smell coming into the passenger area, with the air conditioning "on"?

Could you post an answer for me?

This problem was very frustrating for me, and I hope this info helps you.

 

The canister is needed as a clear air device and is designed catch any unused gas that is in the system althought they should not fill with gas this is a bad thing (FIRE!!!!):nono: On warmer days you will get more gas emissions into the canister and it may smell a little. if it is a strong odor than the canister is prolly bad. I do not remember where I read but you can't discontiue the canister or the car will not run right I think its about vacume. I would not block the hose off, they don't cost much just replace it.

 

I now have a 1991 Z28 5.7 and yes, the gas smell does come into the passenger area with the air conditioning on. I usually turn off the air and open the windows to clear out the smell. I will try another canister, but I wonder if there is a check valve or something from the fuel tank that is supposed to keep the liquid fuel from reaching the vapor canister and contaminating it. Thanks for your feedback, at least I now know that other cars have had the same problem.

 

I have a 88 F IROC and had a similiar problem. My system was fitted with two vaccum control valves, one between manifold and soleinod and another between the canister and tank. The canister has a drain (open to air) hose or like mine a capped vent. I did two things which seems to help. I removed the vac valve between tank and canister because I felt the vent prevented the second valve from working well. and I replaced the O-ring on my gas cap to insure a good seal. The line from tank to canister should have a filter of sorts inline near the tank end and the connection at the tank is placed in a cavity near the top. I suspect that keeping the tank air tight is important.

 

"On warm days after driving to operating temperature the vapor canister smells like gas. Do they ever need to be replaced? I have checked the line connecting to the solenoid and found drops of gas in the hose. I am considering blocking off the hose, has anyone else had this problem? Thanks for your help."

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There is a valve mounted near the fuel tank called the "fuel tank vent valve". It is a white, plastic valve that is shaped like a mushroom or light bulb. It helps vent fumes from the gas tank. I had mine replaced, hoping it would fix my "gas smell" problem; that was before I found out what it really was.

My "fuel tank vent valve" may have been bad, because on hot, summer days, there would be a "Moooooooo!" sound coming from under the rear end. It sounded like a cow. I don't know if this was a sign of a bad valve, but it was kind of funny.

I don't know if changing this valve did any good or not, but the problem with the canister is the valve mounted on top of it. Remember, you may have to buy several new cansiters, in a row, before you find one that works right.