1. When the engine is turned on, the fuel pump receives an electrical signal from the engine control unit (ECU) or a separate fuel pump control module. This signal activates the pump.
2. The fuel pump draws fuel from the fuel tank and pressurizes it.
3. The pressurized fuel is sent through the fuel lines to the fuel injectors.
4. The fuel injectors then spray the pressurized fuel into the engine's cylinders as required by the engine's operating conditions.
5. Once the desired fuel pressure is reached, a pressure sensor in the fuel line sends a signal back to the ECU or fuel pump control module.
6. The ECU or fuel pump control module detects the sufficient pressure and turns off the fuel pump.
So, the fuel pump runs intermittently, only when needed to maintain the necessary fuel pressure in the system. When the engine is idling or not running, the fuel pump does not operate. However, some vehicles may have slightly different fuel system designs, so it's always best to refer to the specific vehicle's owner's manual for details on the operation of its fuel pump.
