Fuel Tank Vent Problems?
01-14-22, 10:21 AM
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Fuel Tank Vent Problems?
Like a few who have gone before me, I am having fueling problems where the pump keeps clicking off. It was only a mild inconvenience at first, but the weather turned cold (-35C)! On top of that, I occasionally hear gasping sounds from the gas cap as it vents. The last time, I removed the cap and the tank took a big gulp of air. I thought that would relieve it, but 5 minutes later and it was gasping again. My car is a 2012, with 317,000 kms.
So far, I have disconnected the charcoal/vapor canister. I haven't removed it since the 2 pieces will need to come apart to get it through the small gap between the exhaust and the cross-member. I've blown through the canister and am pretty sure it is still good, though the design is different than the canisters I watched being checked in videos, so I might not have blown through the right inlet, or not checked the right outlet. I'm pretty sure I should be blowing air in where the hose from the fuel tank was, and checking for air coming out from the opposite end of the canister where the hose leaves toward the gas cap.
Next I tried blowing through the vent hose that goes from the vapor canister to the gas cap, and I can't blow through that. I managed to disconnect the top of that hose from behind the gas cap, and was able to blow through it fine through just the hose. I read in a prius forum about someone having to take the fuel filler neck out to be able to clear dust and debris from a valve there, but I haven't figured out how to get that off without breaking it or removing the entire quarter panel.
So, if anyone has some thoughts about my canister testing methods, or ideas about whether I should be able to blow out through that hose, and if so, how to clear it, or remove the filler to clear it I would really appreciate it.
Here are some photos:
Here is a pic of the top of the fuel filler neck, with the fuel tank vent hose detached.
Here is another pic of top of the fuel filler neck, this time the half-cylinder piece has been rotated to show where the vent line hose was attached - behind the small permanent vent line at the top. I would like to confirm if there is a valve in the rotating half-cylinder, and if so, should it open to let air out or in? And, I can't figure out how to detach the whole mechanism without breaking it.
Here is a pick of the outside of the fuel filler neck. It looks like there might be tabs there to release the outer plastic ring from the inner plastic ring, but I can't figure out how.
Any suggestions would be greatly appreciated.
So far, I have disconnected the charcoal/vapor canister. I haven't removed it since the 2 pieces will need to come apart to get it through the small gap between the exhaust and the cross-member. I've blown through the canister and am pretty sure it is still good, though the design is different than the canisters I watched being checked in videos, so I might not have blown through the right inlet, or not checked the right outlet. I'm pretty sure I should be blowing air in where the hose from the fuel tank was, and checking for air coming out from the opposite end of the canister where the hose leaves toward the gas cap.
Next I tried blowing through the vent hose that goes from the vapor canister to the gas cap, and I can't blow through that. I managed to disconnect the top of that hose from behind the gas cap, and was able to blow through it fine through just the hose. I read in a prius forum about someone having to take the fuel filler neck out to be able to clear dust and debris from a valve there, but I haven't figured out how to get that off without breaking it or removing the entire quarter panel.
So, if anyone has some thoughts about my canister testing methods, or ideas about whether I should be able to blow out through that hose, and if so, how to clear it, or remove the filler to clear it I would really appreciate it.
Here are some photos:
Here is a pic of the top of the fuel filler neck, with the fuel tank vent hose detached.
Here is another pic of top of the fuel filler neck, this time the half-cylinder piece has been rotated to show where the vent line hose was attached - behind the small permanent vent line at the top. I would like to confirm if there is a valve in the rotating half-cylinder, and if so, should it open to let air out or in? And, I can't figure out how to detach the whole mechanism without breaking it.
Here is a pick of the outside of the fuel filler neck. It looks like there might be tabs there to release the outer plastic ring from the inner plastic ring, but I can't figure out how.
Any suggestions would be greatly appreciated.
