Valve on charcoal canister

[eurasiaoverland]

Hi guys

My 1996 3RZ has a charcoal canister in the engine bay.

Just out of curiosity, what does the valve do on top of the canister? What triggers it to operate? I can't think of any other sensor in the fuel system which might activate it (apart from the fuel level sender perhaps?).

Any symptoms other than fuel smell of a bad charcoal canister?

Not that I'm having any issues, but I've always brimmed the tank to the absolute maximum and read that this can screw up the charcoal element.

I do sometimes hear a hiss (not sure if its positive or negative pressure in the tank) when taking the filler cap off though, suggesting the tank is not venting to atmosphere.

Would be interested to know if anyone knows for sure how the system works.

Thanks

EO

 

[sleepydad]

Hi guys

My 1996 3RZ has a charcoal canister in the engine bay.

Just out of curiosity, what does the valve do on top of the canister? What triggers it to operate? I can't think of any other sensor in the fuel system which might activate it (apart from the fuel level sender perhaps?).

Any symptoms other than fuel smell of a bad charcoal canister?

Not that I'm having any issues, but I've always brimmed the tank to the absolute maximum and read that this can screw up the charcoal element.

I do sometimes hear a hiss (not sure if its positive or negative pressure in the tank) when taking the filler cap off though, suggesting the tank is not venting to atmosphere.

Would be interested to know if anyone knows for sure how the system works.

Thanks

EO

this might help?

https://imgur.com/a/rOVnMns


not specific to 3rd gens but still good information in general
https://youtu.be/g4ClmBASUco?t=247

 

[Tyler James Inc]

The valve is the purge valve. You'll often hear it tapping- sometimes pretty loudly tapping!

 

[eurasiaoverland]

this might help?

https://imgur.com/a/rOVnMns


not specific to 3rd gens but still good information in general
https://youtu.be/g4ClmBASUco?t=247

Thanks, interesting but this is way more involved than what's on my truck! I just have a breather pipe from the tank to the charcoal canister, and one valve venting into the inlet manifold.

The valve is the purge valve. You'll often hear it tapping- sometimes pretty loudly tapping!

I don't think I've ever heard it.

There is an electrical connector to the valve (two wires from memory), what operates this valve? There are no sensors in the tank except for the fuel level sender.