What Causes the Popping Sound in the Engine Compartment at Idle?

1 Answers
DelAvery
07/30/25 9:47am
Excessive carbon deposits in the combustion chamber not only increase the compression ratio (resulting in high pressure) but also create high-temperature hot spots on the carbon deposit surfaces, leading to engine knocking. Below is an introduction to car idling: 1. The Role of Car Idling: Idling is a working condition of a car, referring to the engine running in neutral gear. The engine speed during idling is called the idle speed. The idle speed can be adjusted by modifying the throttle size, among other methods. Idling means the engine is "exerting force without doing work." When the engine is running, if the accelerator pedal is completely released, the engine enters the idling state. 2. Causes of Unstable Idling: Direct causes refer to mechanical parts being dirty, worn, or incorrectly installed, leading to variations in cylinder power output, which results in an imbalance of power among cylinders and causes unstable idling. Indirect causes refer to abnormalities in the engine's electronic control system, leading to poor combustion of the air-fuel mixture, making it difficult to balance the power output among cylinders and causing unstable idling.
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