Why Is My Fuel Tank Not Filling Up and How To Fix It

Are you having trouble with filling your fuel tank? Is your fuel pump shutting off preventing you from filling your fuel tank? Here is why your fuel tank is not filling up and how to fix it.

”The most common reason why your fuel tank is not filling up is because you have a clogged or a faulty evaporative emissions control system (EVAP). The EVAP is designed to collect and store the fuel vapors from the fuel tank and move them to the intake manifold for combustion. If your EVAP is clogged or faulty, you won’t be able to fill your gas tank.”

Why Is My Fuel Tank Not Filling Up?

Why Is My Fuel Tank Not Filling Up and How To Fix It

When you put gas into the car, it displaces the air that’s in the tank and the air has to come out somewhere. Now, in the old days, the air would just come right back out of where the filler was and it would pollute the atmosphere. But, all modern-day cars use a system that’s called an EVAP. It is designed to keep the vapors from polluting the atmosphere by keeping them inside the car.

Evaporative emissions control or EVAP systems have been installed in motor vehicles since 1970. Their purpose is to collect and store fuel vapors from the fuel tank and at the correct time move them to the intake manifold for combustion.

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EVAP systems have changed over the years from simple float bowl and fuel tank vacuum-operated types to fully sealed OBD, to monitored and ECM-controlled systems.

If your evaporative emissions control system is clogged or faulty, it will keep shutting off your fuel pump and you won’t be able to fill your tank with fuel. A solution to this problem can be as easy as cleaning some of the hoses, or it could be as serious as replacing some of the EVAP components.

How Do I Fix My Gas Tank Not Filling?

If your EVAP system is faulty or clogged, you won’t be able to fill your fuel tank. The fuel pump will just constantly shut off preventing you from filling your fuel tank, or just filling it little by little. Here is how to fix a fuel tank that is not filling properly.

1. Run a vehicle diagnostics with a scan tool

Run a vehicle diagnostics with a scan tool

If your fuel tank is not filling up, it is probably the EVAP system. Just to be sure, you can run diagnostics on your vehicle with a scan tool. The P0440 error code is associated with a EVAP malfunction. If you don’t have a scan tool, you can go ahead and proceed with the following steps.

2. Clean the area around the fuel tank cap

Clean the area around the fuel tank cap

The EVAP system can get dirty and clogged from constantly working. Personally, I didn’t care about the area around my fuel tank cap. It was always dirty until one day I got my EVAP system clogged from all the dirt. It is easy for the dirt to get inside the fuel tank. Make sure to clean your fuel tank cap area every time you wash your vehicle.

3. Locate the Evaporative emissions control canister

On almost all vehicles, the EVAP canister is located in the engine bay. If your vehicle is lifted on jack stands, you can just follow the hoses from the fuel tank into the engine bay area. Or, you can read your manufacturer’s manual and see where your EVAP canister is located. The EVAP canister can look differently like shown in the image.

4. Clean the hose connecting to the EVAP canister

Once you locate the EVAP canister, remove the hose that is connected to the canister. You need to clean the hose and the connector on the canister with a paper towel. Wipe the hose and the connector and make sure there are no huge pieces of debris. You can also blow it with an air compressor.

5. Try filling your fuel tank with gas

Go to the gas station and fill your fuel tank. If you only had a clogged hose, you should be able to fill your gas tank. If it still not working, you might need to change the charcoal canister.

6. Get your EVAP charcoal canister replaced

EVAP charcoal canister replaced

The hose that you cleaned from the previous step is connecting to a canister that is full of charcoal. When the air is pushed through there, it vents hydrocarbons out of the air and then just vents pure air into the atmosphere. This prevents the gas fumes from polluting the atmosphere. When the EVAP charcoal canister is clogged, it has to be replaced with a new one.

Why You Shouldn’t Overfill Your Gas Tank

”You shouldn’t overfill your gas tank because once the fuel pump shuts off, pouring more gas could get in the EVAP canister and clog it up. You cannot clean the EVAP canister, only replace it.”

Modern vehicles have what is called EVAP systems. Instead of the gasoline vapor escaping to the atmosphere, it’s recycled and burned inside the engine. The EVAP canister filters out the hydrocarbons and lets pure air come out when it needs to filter it out.

These EVAP canisters work great for filtering out gasoline fumes. But, if you are filling your gas tank and the fuel pump shuts off, if you pump extra in, you can pump liquid gasoline and that will get into the EVAP canister. If liquid gasoline gets inside these EVAP canisters, it destroys them.

Replacing an EVAP canister can cost as much as $380 and another $240 for labor. So, you don’t want to waste all that money just because you put extra gas in the car. These canisters are getting smaller and smaller, so just a little bit of gasoline can ruin them.

Remember, once the fuel pump goes off, do not pour more gas in the fuel tank.

Vide Polowenski

General Mechanic with over 20 years of experience specializing in General mechanics, exhaust systems, fuel systems, and fuse-related problems.

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