What Causes Smoke from the Exhaust Pipe?

[EvelynRose]

Here are the reasons for smoke from the exhaust pipe: 1. When the car is cold, white smoke from the exhaust pipe is particularly severe, but this does not occur when the car is warm. This happens because gasoline contains moisture, and when the engine is too cold, the fuel entering the cylinder does not burn completely, leading to the formation of mist or water vapor, which appears as white smoke. This phenomenon mostly occurs during the first start-up in winter or the rainy season. No repair is needed in such cases, as the smoke will naturally disappear once the engine temperature rises. 2. Black smoke from the vehicle indicates that the air-fuel mixture is too rich and combustion is incomplete. This is mainly caused by the following four reasons: the fuel level is too high, resulting in an overly rich mixture; malfunction of the vacuum economizer, causing an inappropriately enriched mixture; clogging of the main air bleed jet; or a blocked air filter.