What Causes Abnormal Noise After Starting the Car?

[DeGemma]

Abnormal noise after starting the car can be caused by insufficient engine oil, poor fuel combustion, or premature fuel supply. Below are detailed explanations: Insufficient Engine Oil: When engine oil is insufficient, various components cannot be properly lubricated, leading to increased wear and noise. Adding engine oil can resolve this issue. Poor Fuel Combustion: Low injection pressure, dripping injectors, poor fuel atomization, or delayed fuel supply can cause poor fuel combustion, resulting in knocking. The injectors should be removed for inspection and adjustment, and the fuel supply timing should be adjusted. If necessary, replace the components to meet specifications. Premature Fuel Supply: If the fuel injector starts spraying before the piston reaches the designated position, fuel combustion occurs prematurely. The high-pressure gas in the cylinder impacts the piston, producing a rhythmic knocking sound, which becomes more noticeable when reducing the throttle. Adjusting the fuel injection timing can resolve this issue.