Why does the fuel pump nozzle shut off before the tank is full?

[MadelynFitz]

If the fuel pump nozzle shuts off before the tank is full, it is likely because the nozzle is pressed too tightly. Simply loosen the nozzle slightly and continue fueling. The front section of the fuel pump nozzle has a sensor that automatically shuts off the nozzle when it comes into contact with fuel to prevent overflow. If fuel flows too quickly, it may splash up and trigger the sensor, causing the nozzle to shut off prematurely. Here are additional explanations for why the fuel pump nozzle shuts off before the tank is full: 1. Welding issues in the blow-molded fuel filler pipe—while blow-molded products are generally stable, welding can sometimes result in excess material or misalignment, leading to a narrow fuel flow path. 2. The one-way valve at the end of the fuel filler pipe may be stuck; if the spring is jammed, fueling becomes impossible. 3. There is a small hole at the bottom of the fuel pump nozzle’s tip with a sensor to prevent fuel from overflowing the tank. When the fuel level approaches the tank opening and covers the nozzle’s tip, it triggers the sensor, causing the nozzle to shut off and stop fueling.