What Causes Black Smoke When Starting a Car?

[MaggieFitz]

The reasons for black smoke when starting a car are as follows: 1. Overly rich air-fuel mixture: It is necessary to check whether the oxygen sensor has failed. If the oxygen sensor fails, the vehicle loses its ability to automatically adjust the fuel injection volume, making it easy to produce black smoke when the accelerator is pressed hard. Corresponding parts such as the air filter, fuel injector, valve seal, cylinder liner and piston, and oxygen sensor need to be repaired or replaced. 2. Excessive fuel impurities: If low-quality fuel is added, gasoline will produce many impurities after combustion. It is advisable to refuel at reputable gas stations. 3. Decreased or failed spark plug performance: The spark plug is the component that ignites the combustible mixture. If the spark plug ages, it cannot effectively ignite the gasoline, leading to incomplete combustion. In this case, the only solution is to replace the spark plug.