Why Does a Car Emit Black Smoke?

[MacAthena]

Reasons for a car emitting black smoke: 1. Uneven or excessive fuel supply from the high-pressure fuel pump to each cylinder can cause unstable engine speed and intermittent black smoke; 2. Poor quality diesel fuel, which is difficult to ignite, leads to black smoke from the exhaust and also easily causes carbon buildup in the combustion chamber and exhaust pipe muffler; 3. Overly rich air-fuel mixture, resulting in incomplete combustion, which can be caused by various factors such as high fuel pressure, poor ignition performance, or inaccurate signals from the intake pressure sensor; 4. Severe wear of the cylinder liner and piston components. In this case, the piston rings do not seal properly, causing a significant drop in cylinder pressure, which prevents the diesel from burning completely and results in black smoke. Additionally, the engine power drastically decreases, and in severe cases, the engine may shut down automatically.