What Causes the Continuous Buzzing Sound After the Car is Powered On?
2 Answers
When the car is powered on, the continuous buzzing sound is caused by the operation of the fuel pump. Once powered, the fuel pump starts working to prepare for engine ignition. Additional Information: 1. Function of the Fuel Pump: The fuel pump's role is to draw gasoline from the fuel tank and deliver it through the pipelines and fuel filter to the carburetor's float chamber. Thanks to the fuel pump, the fuel tank can be placed at the rear of the car, far from the engine, and positioned lower than the engine. 2. Types of Fuel Pumps: (1) Diaphragm-type fuel pump: A representative of mechanical fuel pumps, used in carburetor engines, typically driven by an eccentric wheel on the camshaft. (2) Electric fuel pump: Unlike the diaphragm-type, it operates via electromagnetic force to repeatedly move the pump diaphragm. This type of electric pump allows flexible installation locations and helps prevent vapor lock issues.
As a veteran driver with ten years of experience, I've also encountered the buzzing sound after power-on, which is usually caused by several situations. The cooling fan system may automatically start after power-on—check if the cooling fan under the front hood is running. The fuel pump also emits a buzzing sound when delivering fuel, sounding like something is spinning in the engine bay. Loose relays or electronic component connections can also cause continuous noise. It's recommended to first turn off and restart the engine. If the sound persists, take some time to check if the battery connections are secure and, if necessary, use a multimeter to test whether the voltage is stable. If the issue remains unresolved, drive to the repair shop immediately for inspection—don't push through and compromise driving safety.
