What Are the Effects of Fuel Pump Auto-Shutoff?

[JanelleLee]

When the fuel pump automatically shuts off ("jumps the gun"), gasoline may overflow through the vent hole. If exposed to an open flame, it can ignite instantly, causing irreversible damage. Additionally, overflowing gasoline can easily enter the fuel lines, damaging the carbon canister and causing spark plug malfunctions, which may result in the vehicle failing to start. 1. Difficulty starting and unstable idle: Overfilling the fuel tank can cause gasoline to enter the carbon canister lines, reducing its efficiency or even rendering it ineffective. This gasoline can then flow into the intake manifold during startup, "drowning" the spark plugs. This leads to symptoms such as engine idle vibration, stalling during acceleration, or failure to start, and can also cause severe carbon buildup in the engine and intake manifold. 2. Fire hazard risk: An overfilled fuel tank, combined with thermal expansion, can lead to excessive vapor emissions, significantly increasing the risk of fire.