What Causes Blackening of the Exhaust Pipe?

[DelDallas]

Here are the reasons for the blackening of the exhaust pipe: 1. Due to limitations in gasoline refining technology, equipment, and conditions, there are always some impurities in the fuel, resulting in lower fuel quality. Fuel quality significantly affects vehicle emissions. Poor-quality fuel not only causes incomplete combustion but also leads to carbon buildup inside the engine, increasing exhaust emissions. Over time, black soot appears at the exhaust pipe, causing it to blacken. 2. For a car engine to operate normally, besides fuel, it requires a large amount of air. The optimal air-fuel ratio is generally 14.7:1. However, in many older vehicles, the oxygen sensor may malfunction, preventing the air flow from reaching the required ratio. This results in incomplete combustion of gasoline in the engine, producing large amounts of gray-black smoke and causing the exhaust pipe to blacken.