The maintenance technicians disassembled the 0R-3002 injectors and found that the internal filter screen was completely blocked by impurities and colloids, and the fuel could not pass through the filter screen smoothly, resulting in insufficient fuel supply. The reason for the clogging was that the fuel filter was not replaced regularly, and the impurities in the fuel entered the injectors and accumulated on the filter screen. In addition, the fuel had been stored for too long, leading to colloidal precipitation.