1, diesel oil is not clean, there are impurities in the high-pressure oil pipe, so that the needle valve coupling is not strictly closed, the high-pressure gas in the combustion chamber is channeling back, and the needle valve coupling is burned out. In addition, the injector pressure regulating spring, tappet and other parts of the dirty things through the injector tappet moved to the upper part of the injector needle valve, or on the oil road to prevent oil leakage of cotton rope, lead wire through the high pressure tubing into the injector, will make the needle valve parts stuck.
2, the machine temperature is too high, the injector cooling is not good, resulting in the needle valve parts stuck. But the oil supply time is too late, the cooling channel scale is too much or blocked, the pump impeller end face wear, the engine long-term overload and so on will make the engine overheat.
3, the oil valve wear, so that the fuel injector stops the phenomenon of dripping oil, resulting in the nozzle burning coke carbon, stuck fault.
4. When the injector is installed, the gasket or gasket is damaged, resulting in air leakage, causing the local temperature of the injector to be too high and stuck.
5, injection pressure is too low, resulting in high pressure gas backchanneling in the combustion chamber;
6, parts manufacturing reasons, such as cylinder head injector installation hole and injector match too tight, needle valve body and cylinder head on the installation hole gap is too small, cylinder head injector installation hole processing is too deep.