The maintenance technicians tested the injectors and found that the injection flow rate of each 0R-3190 injector varied greatly, with a difference of more than 15%, which led to uneven power output of the engine. After disassembling the injectors, it was found that the nozzle holes were severely worn, and the shape of the nozzle holes was deformed, resulting in uneven fuel injection. The reason for the wear was that the excavators worked in a high-dust environment for a long time, and the dust entered the injectors, causing abrasive wear of the nozzles.