What Causes a Lean Air-Fuel Mixture in a Car Engine?

[AlexanderAnn]

Here are the reasons for a lean air-fuel mixture in a car: 1. Insufficient fuel injection: Various intake sensors fail to accurately detect the intake air volume, leading to inadequate fuel injection. 2. Excessive carbon deposits: Fuel is absorbed by carbon deposits. 3. Failure of the oxygen sensor's closed-loop control. Below are the effects of a lean air-fuel mixture: When the mixture is too lean, the combustion speed of the fuel decreases, and part of the mixture may burn while the piston moves toward the bottom dead center. A lean mixture can cause higher idle speeds, and when accelerating and releasing the throttle, the engine speed may struggle to drop back to idle quickly. If you remove the spark plug at this time, you will notice that the electrode color is white, confirming that the combustible mixture is too lean.