What Causes the Pungent Smell of Car Exhaust?

[MichaelAnn]

Reasons for pungent car exhaust: 1. When the three-way catalytic converter fails or becomes clogged, it cannot effectively filter the exhaust; 2. During cold starts, the engine typically injects a richer air-fuel mixture to quickly reach operating temperature, resulting in a stronger exhaust smell, which is normal; 3. When the engine's air-fuel mixture is too rich, incomplete combustion of gasoline occurs, leading to carbon buildup and heavier exhaust odor; 4. Using low-quality fuel with excessive impurities also negatively affects emissions, so it's advisable to refuel at reputable state-owned gas stations.