What is the reason for black smoke coming out of the SsangYong Actyon's fuel injector after cleaning?

[MelanieFitz]

The reason for black smoke coming out of the SsangYong Actyon's fuel injector after cleaning may be incorrect ignition timing or an overly rich air-fuel mixture. Incorrect ignition timing: This can also cause incomplete combustion of the air-fuel mixture; or if a few cylinders in the engine are not working, a small amount of black smoke may be emitted. If the engine's exhaust pipe emits a small amount of black smoke accompanied by a rhythmic "popping" sound, it can be determined that a few cylinders are not working or the ignition timing is incorrect. The non-working cylinder can be identified using the cylinder cut-off method, or the ignition timing can be checked and adjusted. Overly rich air-fuel mixture: This means the air-fuel mixture in the cylinder has an excessively low air-to-fuel ratio, leading to incomplete combustion. Some fuel decomposes into free carbon at high temperatures and is emitted from the exhaust pipe, forming black smoke. If the engine's exhaust pipe emits a large amount of black smoke accompanied by a backfire sound, it can be determined that the air-fuel mixture is too rich.