strange problem gassing up car

[terracore]

I can't pump gas into my car. When I try to pump gas the pump immediately shuts off like the tank is completely full but the empty fuel gauge and common sense tells me that's not possible. No, I haven't forgotten how to pump gas, and I've tried different combinations including depth of nozzle insertion, speed of gas flow, orientation of the nozzle handle, and different gas pumps at different gas stations. It won't pump at all at Safeway and I can only get it to pump at Aloha if the gas drizzles in slower than an old man peeing.

I googled the problem and it's likely a malfunction of the vapor reclamation that vents the gas vapor to the charcoal cylinder but I've never "topped off" after gassing up (apparently a common cause of early charcoal canister failure) and the car only has 20,000 miles on it. It's a 2008 Impala.

Before this problem started I had put about 10 gallons of year-old gas into the car as part of my storm preparation getting new gas for this season and at first I thought maybe I physically damaged a gasket or something with the plastic gas can neck but I looked up the car's gas hole with a flashlight and there is nothing but smooth neck extending much further than my plastic gas cans can reach so any type of damage in that respect is very unlikely. It is possible adding the old gas and this problem beginning has coincidental timing and they were about 2 weeks apart.

I haven't started any serious diagnosis yet because I was wondering if there was a Hawaii climate related issue that I should be considering?

Also, the check engine light is NOT on and I understand there are sensors that should alert if there is a problem with the fuel system like a backup in the vapor venting or clogged charcoal canister.

Any ideas?

[Linchpin]

This happened to me on my old YJ many moons ago.
Turned out, the filler neck had collapsed for some unknown reason. I was only able to get a little gas in before it backed up and triggered the vacuum closure on the nozzle.
I did troubleshooting for a few days until my neighbor suggested trying to put 5 gallons in from a gas can. That's when I realized what was going on.

[Tink]

Check the evaporate line and pump, found behind fender at about 5 o'clock from filler is working. Thre should be a fuse in the main box, but can't remember where to check current, but if good with voltage tester you could check while running.

Community begins with Aloha

[ericlp]

I have this problem with my old toyota. I think my problem is a clogged up charcoal canister. Never top off, when it clicks off don't keep adding.

I find if I keep the nozzle out about 6" this lets the fumes escape without triggering the pump to click off. Also, sometimes this doesn't work, and I have to find a rotation position on some pumps in order to get gas into the tank.

I suppose you could always carrier around that 10 gallon gas can, fill it up then transfer it to the car for a solution till you can fix the problem.

[kimo wires]

Pumps are designed to shut off automatically if the fuel backs up. Its the angle at which you pump. If the pump clicks off its probably because the fuel dispensing nozzle isn't lined up with the restrictive hole at the top of your gas tank. Most fuel tanks are designed with a narrow opening near the top (input) to prevent siphoning. so if the angle that you are holding the pump makes fuel splash back it will cut off. Try pulling the "male" dispensing nozzle back a little and it should work.

[MarkP]

It's not just the angle at which you put the nozzle. There is a complex system in modern cars that seeks to absorb the gasoline fumes that are expelled as the tank fills. The tight fit of the filler neck around the nozzle is designed to force the fumes to go through the charcoal canister. The connection of the canister to the tank is itself not just a nipple off the top of the tank. There are roll-over valves built in to seal the opening if the car winds up upside-down. On my vehicle, a Ford Ranger, there is a solenoid valve in the vent line too. Not sure when that is supposed to be closed but if it breaks it could break in the closed position. Then there is the carbon canister itself and finally there is an air filter of sorts to keep dirt and bugs out of the system. There are multiple ways that the system can fail. The Ranger is notorious for such failures and mine takes forever to fill. You must just barely crack the nozzle open or it immediately shuts off. I have tried getting the roll-over valve out of the top of the tank but there is no room to work and it is glued in by 17 years of gunk.

[ericlp]

yeah those EPA people are making it harder for us to fill up the tank.

One thing you might consider is to pull off any rubber hosing coming out of the tank filler neck. If it fills up like normal then you know you got a clog someplace in that area.

[terracore]

Thanks for all the tips and tricks. I won't have time to look into it further until this weekend but with Punaweb and the internet I have at least a few good leads to try before I give up and take it to Curlees.

[mac nut]

Probably the rubber fill hose has partially kinked itself. Some fuel hoses like in my ford ranger make a 90 degree turn and if the hose gets old it can kink here so gas does not flow into the tank properly. put it up on a hoist and look at the fill hose. I replaced my ranger hose for around 40 dollars off amazon

[MarkP]

I would love it if it were that easy. I did check but I didn't get my hand right on the point of attachment of the main filler hose to the tank.