Why is there a strong gasoline smell during cold starts?

[StArianna]

The reasons for a strong gasoline smell during cold starts are as follows: 1. Low external temperature. When the water temperature and exhaust pipe temperature are low, combined with the extremely cold external temperature during winter driving, the air-fuel mixture becomes richer. As a result, some of the mixture cannot be fully burned and is directly expelled through the exhaust pipe, leading to a noticeable gasoline smell. 2. Issues with the carbon canister or carbon canister solenoid valve, causing an overly rich air-fuel mixture during startup. 3. Low local temperatures combined with excessive carbon buildup inside the engine can lead to poor atomization of the air-fuel mixture, also resulting in this phenomenon. 4. If the solenoid valve remains closed, gasoline vapor in the carbon canister will accumulate until it fills the canister, forcing excess vapor to escape into the atmosphere, which can also produce a gasoline smell. 5. Leakage in the fuel injectors can cause an overly rich air-fuel mixture, and unburned mixture expelled through the exhaust pipe will result in a strong gasoline odor.

[VonLeilani]

The smell of gasoline when starting the car is mainly because, in a cold engine state, the engine requires a richer air-fuel mixture to assist ignition. The electronic control unit automatically increases the fuel injection volume, leading to unburned gasoline being expelled through the exhaust, thus creating the odor. Another reason could be a malfunction in the carbon canister of the fuel tank evaporation system, allowing gasoline vapors to escape directly; or a leaking fuel injector letting fuel seep in. This situation is normal when it occurs briefly and is not a major concern. However, if the smell is strong and persistent every time you start the car, it might indicate a fault in the fuel line or fuel supply system. I've seen many older cars with this issue, so it's advisable to promptly check the evaporation canister or replace the oil seal to prevent potential hazards, avoid fuel wastage, and even prevent safety issues.

[McMarcus]

I've driven many cars, and the smell of gasoline during cold starts is quite common. Mainly, when the engine is cold, it's harder to start, so the system injects more gasoline to assist ignition. The excess that doesn't burn comes out as the smell. But you should be careful—if the smell is always strong and pungent, it could be due to aging fuel lines leaking or the charcoal canister getting stuck, causing gasoline vapors to escape excessively. My experience is to have the technician check the evaporation system during regular maintenance, which can save a lot of trouble. As cars age, parts wear out easily. Whenever I smell something off, I schedule a repair right away—it saves money and gives peace of mind.

[StArcher]

A gasoline smell during cold starts is common, as the engine requires a richer fuel mixture at low temperatures, leading to incomplete combustion and odor emission. If the issue persists, check for a clogged carbon canister in the evaporative system, leaking fuel injectors, or a loose fuel tank cap. These faults are more likely in older vehicles—visit a repair shop for diagnosis.