Why Does the Exhaust Pipe Smell Strongly of Gasoline When Starting a Cold Engine?

[VanJosephine]

There are several main reasons for a strong gasoline smell when starting a cold engine, which are: 1. Under very low external temperatures, when the water temperature and exhaust pipe temperature are low, combined with the extremely cold external conditions during winter driving, the air-fuel mixture becomes richer. As a result, some of the mixture cannot burn completely and is directly expelled through the exhaust pipe, leading to a noticeable gasoline smell. 2. Issues with the carbon canister or its solenoid valve can cause an overly rich air-fuel mixture during startup. 3. If the local temperature is low and there is excessive carbon buildup inside the engine, the air-fuel mixture may not atomize properly, also contributing to this phenomenon. 4. If the solenoid valve remains closed, gasoline vapors in the carbon canister will accumulate, eventually filling the canister. Any excess vapors will escape into the atmosphere, resulting in a gasoline odor. 5. Leakage from the fuel injector can lead to an overly rich mixture, and the unburned mixture may exit through the exhaust pipe, causing a strong gasoline smell.