Why is there a gasoline smell after starting the car?
2 Answers
If there is a strong gasoline smell when starting the car, but it disappears after the engine warms up, this is a normal phenomenon. This occurs because the combustion efficiency is poor when the car is first started. Below are relevant details: During cold starts: The water temperature and exhaust pipe temperature are low, and the air-fuel mixture is richer, leading to incomplete combustion of some of the mixture, which is then expelled through the exhaust pipe. This results in a noticeable gasoline smell, which is normal. During winter starts: Especially in winter, when the outside temperature is very low, the car cannot reach its normal operating temperature immediately after starting. At this time, the engine control unit (ECU) increases the fuel injection volume based on intake air temperature and coolant temperature signals. The increased fuel injection, combined with a small amount of unburned fuel vapor being expelled, leads to a stronger gasoline smell.
I smelled gasoline while driving my own car before and was quite worried. It turned out to be mostly an issue with the fuel system. The most common causes are cracks in the fuel line or fuel tank leading to leaks, or the fuel cap not being tightened properly, allowing gasoline to evaporate into the air. Additionally, during cold starts when the engine hasn't warmed up yet, incomplete combustion of gasoline can release excess odor. A faulty charcoal canister may also cause the smell to escape. The key is not to ignore it—if you smell it, you should stop in a safe place and check. If it's a major leak, it could potentially cause a fire. I remember one time the fuel line fitting was loose; luckily, it was fixed in time, otherwise, the repair would have been more expensive.