What is the reason for the fuel gauge not changing after adding 4 liters of fuel?

[OGenesis]

It could be caused by the fuel float being stuck, aged, or damaged and leaking fuel, preventing the float from properly floating on the gasoline. Instead, it may remain suspended in the fuel or sink to the bottom, leading to inaccurate measurements or no response. The solution is to remove and inspect the fuel pump. Below are some related explanations: 1. How the fuel gauge works: There is a float (fuel float) in the car's fuel tank, which is connected to a sliding resistor. As the fuel level in the tank changes, the potential at the measuring terminal also changes. The car's instrument processes this signal and displays the corresponding value, which represents the remaining fuel in the tank. 2. The function of the fuel gauge: The fuel gauge primarily shows the amount of fuel to prevent the car from stalling on the road, reminding the driver to refuel in time. It uses a fuel level sensor to transmit signals, which is a damping-type sensor that relies on the up and down movement of the fuel float to change resistance and transmit signals.