What causes excessive black exhaust?

Excessive black exhaust is primarily caused by an improper fuel mixture entering the combustion chamber, which often results from defective injectors or the use of the wrong fuel type. When the injector is faulty, it may either deliver too much fuel or atomize it poorly, leading to incomplete combustion. This scenario produces an abundance of soot and unburned hydrocarbons, which manifests as black smoke in the exhaust.

Using improper fuel can also contribute to this problem. Fuels that do not meet engine specifications can burn inefficiently, resulting in similar black smoke production. Ensuring that both the fuel type is correct and that the injectors are functioning properly is crucial for achieving optimal combustion and minimizing black exhaust emissions.

The alternatives provided relate to other aspects of engine performance but do not primarily account for the occurrence of black smoke in the exhaust.