charcoal cannister/bypass valve troubleshoot

[strad]

Okay, problem is that on a really hot day (and only then) I get strong smell of fuel in the vicinity of the charcoal canister. Things I know so far:
1: bypass valve connector shows battery voltage with ignition on (per Bentley)
2: bypass valve makes a "click" (per Bentley) with ignition on.
3: There are no apparent fuel leaks anywhere else in the engine compartment. Everything's really clean, so if there was a leak I think I'd see it.

What I need to know is, is there anything else not stated in Bentley that would help me test the bypass valve, and, if any of you have had this problem before, what was/were the fixes you employed. I'm interested in doing this one by the book, so that if I move back to CA (like that'll ever happen lol) I won't get hell trying to smog the thing. Plus I don't like the smell of fuel when it's not supposed to be there.

[36brua]

check that the rubber hose on top of the bypass valve is still connected under the throttle body ?

[strad]

Yes, it is. I'm pretty sure this is not a connection problem. Every hose and hose clamp under the hood is new, except for the one connecting the canister to the firewall. I was just wondering if, on a hot day, my charcoal canister is getting more vapor than it can handle and somehow venting it. Do these things get tired after 17 years?

[nando]

charcol canister is probably done. I know mine is pretty nasty, I don't even like touching the thing.