If you have a gas pump that keeps clicking off when you are filling up, and the tank is not full, there are three main causes.
Causes include a bad EVAP vent valve, charcoal canister, or rollover check valve.
Each part will need to be checked to see what component has failed.
Why Does a Gas Pump Nozzle Keep Clicking Off?
A gas pump gas nozzle will shut off any time it detects gas close to the tip of the nozzle.
This includes gas vapors which can build up pm the tip and cause it to shut off.
What is the Most Common Cause of a Gas Pump That Keeps Clicking Off?
The most common cause is a vent valve that is stuck, closed, or clogged up.
When gas pours into the gas tank, it displaces air and gas vapors that need to be vented out of the tank.
If the gas vapors are not vented out, they will go out of the filler tube and trigger the gas pump to shut off.
Why Does the Gas Pump Keep Clicking Off When Filling Up the Tank?
- Vent Valve
- Charcoal Canister
- Rollover Check Valve
A vent valve is a part of the EVAP system and allows for the gas vapors to be vented out of the system.
A vent valve that is stuck closed or clogged up will not allow the vapors to vent out of the system.
This causes the vapors to go out of the filer nozzle, which triggers the gas pump to shut off.
The vent valve will usually give an error code when it fails, which can be read with an OBDII scan tool
The charcoal canister is also a part of the EVAP system and usually has the vent valve built into it.
The EVAP canister stores the gas vapors until they can be fed into the engine to be burnt away.
It is full of small activated carbon pellets that can absorb fuel vapors.
The gas vapors filter through the carbon pellets and then are vented out through the vent valve.
A bad charcoal canister can become clogged up as the carbon pellets deteriorate and block the flow of the gas vapors.
Some vehicles have a rollover check valve at the bottom of the filler tube.
If the filler tube becomes stuck closed, or blocked, the fuel will not go into the tank and fill the tube.
While not very common, the check valve can cause issues sometimes and need to be replaced.
Summary
When a gas pump nozzle keeps stopping when fueling up and the tank is not full, it is usually an issue with the vent valve, but it can also be caused by other components.
The vent valve allows the gas vapors to escape when gas goes into the tank; otherwise, they go out of the filler tube and trigger the pump to shut off.
When a vent valve fails, there is usually an EVAP code which can be read with an OBDII scan tool.
If you do not have a scan tool automotive store will usually come out and scan codes for free.
A clogged up vapor charcoal canister can also cause a problem since the gas vapors can not vent.
If your vehicle has a rollover check valve at the bottom of the filler neck, it can sometimes become stuck closed and cause the issue.
Have you had issues with a car or truck that keeps shutting off the gas pump when fueling up? Let us know your thoughts below.