It takes 20 minutes to fill my gas tank. this has just started. The fuel keeps backing up in the filler neck and the pump keeps kicking off.

There is an automatic valve in the filler neck of your fuel tank that is designed to keep gas from jumping back up the filler neck and out the fill fitting. If that valve is bad, you'll have a heck of a time filling the tank, as the nozzle is constantly kicking off and your fill rate is VERY slow. Probably best to take it to a dealer or your trusted mechanic. They might want to replace the flapper at the same time.

Check the filler neck for foreign objects like a piece of syphon hose.

Be carfull when using a light around fumes though.

Or they also have a piece of hose which connects filler neck to fuel tank which could be collapsed or kinked.

HI Bridgette,

Due to the different shapes of fuel tank filler necks in cars & trucks, it may be necessary to vary one or more things to allow fuel to flow uninterrupted until the tank is really full.

The main problem can come from the new "vapor recovery" gasoline pumps. These pumps and hoses actually recover gasoline fumes from your tank as the liquid gasoline displaces the air / fumes in the tank is it is being filled. If gasoline flow is started at full blast, it can splash back slightly, causing liquid to be pulled back by the pump - so it shuts off. So, start with a slow rate of filling and gradually increase flow rate to maximum over 5 to 10 seconds. If it still shuts off, try some of the suggestions below.

First, don't fill at maximum flow rate from the pump - that is, don't set the nozzle for wide open. Select one of the other "latches" on the handle instead of the fastest flow and let the tank fill entirely at this rate.

Second, you should experiment a bit with the length of nozzle that you push into the tank's filler neck. If you push it in too far or too little, the pump nozzle can do what you're describing.

Third, try twisting the nozzle slightly so that it doesn't hang straight downward - a little to the left or right may provide a solution.

Lastly, try a different gas station. Their pumps may not be so picky with your tank's filler neck.

Good luck!

You may have a problem with the fuel tank vent valve. This lets air into the tank as you use fuel and allows air out of the tank as you refill with fuel. If the valve is plugged or stuck shut the fuel nozzle will kick off as you try to refill the tank because the fuel can't get through the fill neck and into the tank as fast as it's being pumped in and will back up high enough to kick the nozzle off. Hope this helps and good luck!

i`m guessing that you have tried to install the nozzle in different places in the filler neck while filling the car.if this you have tried then you may have a bad vent valve that is not working properly causing excess air pressure in the fuel tank shutting off the nozzle.have a shop check this out for you.

the vent tube is in the filler neck, quite often the gas tank needs to be dropped to remove it

the block you encounter in filler neck is an anti-siphon device most problems go away but if persistent can have a problem with evap system
Problem filling my gas tank Automotive Fuel Tank Problems Car Repair Information From MasterTechMark Why can fill my gas tank in one go

check the filler neck. the hose may have a kink in it. also check the return line it may be pluged.

I am having the same problem. When turning the pump on full speed it will pump for a few seconds before kicking the pump off like the tank is full even though there is no gas in the tank. I can pump gas if I barely start the pump and hold it by hand but very very slowly so it takes about 20 minutes to fill up. Its not the gas station or the way I am holding the nozzle as I have stopped 20 different places and tried every way imaginable to hold the nozzle. I have changed the filler neck, charcoal canister, and the sensor/filter that is on the side of it that I believe opens to allow fuel vapor to escape and let pressure off the tank when the truck is not running... still no luck. When I had the fuel next off there is a check valve that is made into the top next part of the tank that is spring loaded. I figured this was to keep gas from running back out in the event of a rollover and possibly keep someone from putting a hose down the next and stealing gas. At this point that is the only thing that could possibly be causing the pump to contiune to kick off every few seconds when filling up the tank. Next is to change the tank I suppose unless someone has already ran into this issue and can tell me what I need to do to fix the problem.

have toyota or any machanic check the filer in the gas filler tube.