Diesel Injector Fuel Injector 0445120277 Bosch for FAW J6 Ca6dm2 Xichai Engine

Injector plunger stuck
After analysis, it was found that the plunger (and cylinder) of the faulty fuel injector all had roughening on the surface. Through the analysis of the data, it is found that a large number of injectors still have jamming failures within the operating time of 0-500h (far below the design life of the injector). In order to better explain this phenomenon, the faulty injector within 0-500h is disassembled. It was found that the plunger of the injector was severely roughened, and there was no carbon deposit and other impurities in the plunger groove. According to this phenomenon, it is basically determined that the most important reason affecting the service life of the injector is that the gap between the plunger and the plunger sleeve is too small, which leads to the jamming of the plunger.
4.2 Injector reverse leakage (accounting for 25.6%) The phenomenon that fuel leaks into the oil head coolant is called reverse leakage. Through dismantling, it was also found that the needle valve stuck phenomenon existed in the fuel injectors with reverse leakage. Simultaneously statistics finds: after fuel oil temperature exceeds 97 ℃, the back-leakage phenomenon of fuel injector will increase.
Positive and leaky (accounting for 3.28%)
The phenomenon that the oil head cooling oil leaks into the fuel and burns is called positive leakage.
It was found on site that the failure rate of the fuel injector fluctuated greatly with the oil product. After testing, it was found that when the fuel temperature increased to 102C (at this time, the kinematic viscosity of the fuel dropped to 6Sct), the plunger basically did not get stuck: but because the temperature was too high after the injection The increase in the failure rate of positive leakage and reverse leakage of the fuel injector confirms the previous conclusion: the main reason affecting the service life of the fuel injector is that the gap between the plunger and the plunger sleeve is too small, causing the plunger to be stuck.
Through the above comprehensive analysis, it is determined that the cause of the problem is: due to the change of fuel quality, the gap between the injector plunger and the needle valve is too small, which makes it unable to adapt to the new operating conditions and increases the failure rate.