How can I tell if it's clogged or full? I looked into the FSM, but it's not really helping by "look at canister for cracks". I'm definitely venting fuel vapor under the hood, as I can smell it as soon as I get out of the car after running it. The location of the offending odor is in the general area of the charcoal canister. I don't want to remove it, and vent the vapors to atmosphere from the tank as was stated in another post, but I REALLY DON'T want it venting next to the header either. What should I do/check/replace or whatever to keep from blowing my hood off in the near future? Help Please!

 

sure it isn't a leaky fuel pressure dampener?

 

Positive. The smell comes from the canister area, and vent tube. There's no fuel leak at the PD or fuel lines or fuel rails, and they are 100% dry all around. That was what I first suspected due to posts I've come across and read and had caused me extra worry But no, it most certainly has something to do with the CC and or lines in connection with it.

 

I have the same problem, thought it was my PD, but it comes from the cannister (pass side) and you can also smell it coming from the little tube in the oil filler neck. I also removed my UIM and checked PD - bone dry.
I'd be interested in a solution. Perhaps the cannisters wear out or a check valve is bad?

 

Look in the FSM for a schematic of the evaporative emissions control system. Check all of the hoses that connect the fuel tank, charcoal cannister and purge valve.

 

do you park on a lot of hills facing downward?

do you keep pumping gas into your tank after the thing clicks the first time?

 

no and no, I think most likely the tubes have gotten hard and no longer seal.

 

I have a double negatory there too. I wouldn't think it would be the hoses because this just started within the past say 2-3 weeks. At least that's when I started to smell the fuel. It wasn't bad at first, but it has since become a whole lot worse, enough to make me park it for the time being. I'll double check the lines, and probably the valves, but I would think the check and cut near the tank wouldn't cause the CC to vent fuel in the engine compartment. I'll check with the dealer tommorow to see if the canisters are excessively overpriced, but I may not have much choice if it's bad.

 

Your gas cap could be bad.

 

Gas cap could be bad? How would that cause the problem? (not being sarcastic or anything, just investigating all possibilities) I went to the dealer for the CC and it was like $90. For a flippin' charcoal filter! Needless to say I didn't put in an order for one. I'll be looking into the check and cut valve near the tank and the other check valve leading to the intake today, and replacing all the soft hose lines if I can find the treated rubber hose anywhere. If gas caps aren't too expensive I may pick one up as well. Is there some particular type to get, and are they available at all parts places?

 

I have no charcoal canister. The lines that used to be connected to it are open under the hood. I didn't smell gas for about 10k miles, then I smelled it.

I found that after driving, I could hear and smell the gas vapors coming from the former canister lines.

I thought for a minute about what could have changed to pressurize the lines and therefore the gas tank. I loosened the gas cap and the remainder of the pressure escaped.

I knew I had never heard that sound before when getting gas so it must be the cap. I bought a new gas cap and the problem is gone.

 

You missed part of the question, where did you get one? Thanks.

 

Oops..., I would buy the factory cap. I got mine from the dealer for about $15.

 

Okey dokey . So I take it, you shouldn't have a pressure release while opening the gas cap, just like I've been having lately? I thought the check and cut valve was supposed to deal with this?

 

I see you have '90, unusual providing all lines, etc in satisfactory condition. The '86/'88 are the biggest offenders. High exhaust temps heat the fuel in the tank, vapors get to the canister, and are relieved by the valve. You can even "suck" it into the pass compartment through the evap drain. Usually only happens on extremely hot days. Yes, you can relieve the problem for a short period by undoing the cap and then reinstall until pressure builds again. Yes the system is to be closed so pressure will build again. Put a cap on that vents into the air. No good for pollution, but.

 

Canisters should be ungodly easy to find at the wreckers. There are several check valves in the system, which should be checked as per the factory or Haynes manaul. They can cause the canister to not get purged properly, resulting in it "filling" with vapours.

 

The only time I ever heard the pressure release from the gas tank with my S4 car was during the few days that I smelled gas under the hood. A new gas cap resulted in no more pressure release when removing the gas cap to fill and no more fuel smell under the hood.

It doesn't seem to me that my gas tank should be pressurized. In fact, the only emission testing we have here is to check to be sure that your gas cap's vent is working properly.