Okay, let's refer to this diagram:
For quite some time, I've had the infamous "gas flowing out from the filler gap and down my quarter panel" issue.
When I remove the fuel tank expansion hose (#7 in the diagram) at the filler tube and blow into it, I can feel air moving freely out of its nipple on the filler tube. No blockage there.
I disconnected my gravity valve and tested it, and it's working properly. I squirted some WD40 into both ends and gave it a shake anyway, for good measure.
I can blow air into hose #26, which goes from the tank to the lower input of the gravity valve. Air moves.
I can blow air into hose #25, which goes to the expansion tank in the passenger fender. It's not what I'd call "easy," but it's a long skinny hose and on the other end of the expansion tank is more long skinny hoses (to the charcoal canister and the rest of the emissions evap stuff) so I figure there's some inherent resistance because of that. Bottom line, I can blow air but there's some resistance.
With everything hooked up, I can blow air into the other side of the expansion tank via the charcoal canister hose. About the same level of resistance as when I blow from the other end of the expansion tank.
And just as a control test, I inverted the gravity valve and then tried to blow back to it through that charcoal canister hose and it was totally blocked...as expected.
What am I missing? Does this all sound pretty normal?
I'm thinking that to further troubleshoot this, maybe I should just disconnect the gravity valve altogether for now. From what I can tell, that should at least keep gasoline from backing out of my gas cap.
Oh yeah, the gas cap is the chrome kind with the lock.
What's a guy to do?