Why Does the Car Smell Like Gasoline When Starting?

[IsabelaDella]

It is normal for a car to emit a gasoline smell during a cold start, as most vehicle models experience this phenomenon. However, if the gasoline odor occurs when the car is idling after warming up, it indicates a malfunction that requires prompt repair. The gasoline smell during a cold start is due to an imbalance between the air intake and the injected air-fuel mixture. At the moment of starting, the throttle valve is closed, and air intake relies on the bypass valve. During a cold start, the ECU determines the fuel injection volume based on signals from the temperature sensor and oxygen sensor to achieve the engine's optimal operating condition, resulting in increased fuel injection. If the engine idles for extended periods or operates at low speeds, incomplete fuel combustion may occur. Over time, this can lead to carbon buildup clogging the bypass valve, which affects the engine's air intake to some extent. The imbalance between fuel and air ratios causes some fuel to burn incompletely, resulting in a noticeable gasoline smell inside the car.