What can directly cause faulty operation of diesel engine fuel injection nozzles?

Water in the fuel oil supply is a significant factor that can lead to faulty operation of diesel engine fuel injection nozzles. The presence of water in the fuel can cause various issues, such as corrosion of metal components, formation of rust, and the potential for microbial growth, all of which can interfere with the proper functionality of the fuel injection system.

When water mixes with diesel, it can disrupt the fuel's combustion characteristics, leading to incomplete combustion, engine knocking, and increased emissions. Additionally, water can cause the fuel nozzle to operate inconsistently by affecting the spray pattern and atomization of the fuel, resulting in poor engine performance. Therefore, ensuring the fuel supply is free from water is crucial for maintaining the reliability and efficiency of diesel engines.

The other factors presented may influence the performance of fuel nozzles but do not have the same direct correlation to the fundamental operation of the fuel system as water contamination does. For instance, while a distorted fuel spray pattern can hinder performance, its origin might not be as straightforward as water contamination.