What are the causes and repair methods of nozzle sticking?

1. The main reasons for nozzle sticking: ① The diesel oil is unclean, and there are impurities in the high-pressure oil pipe, which causes the wear of the needle valve coupling of the bending machine, which makes the needle valve coupling not closed tightly, and the high-pressure gas in the combustion chamber flows backwards, burning out the needle valve coupling. In addition, the dirt on the pressure regulating spring and tappet of the injector moves to the upper part of the needle valve of the injector through the tappet of the injector, or the cotton rope and lead wire used to prevent oil leakage on the oil path enter the injector through the high-pressure oil pipe, which will make the needle valve couple stuck. (2) The temperature of the machine is too high, the air door is not cooled well, and the valve coupling of Tiger House is stuck. However, too late oil supply time, too much scale or blockage in the cooling channel, wear of the end face of the water pump impeller and long-term overload of the engine will overheat the engine. (3) The exhaust valve is worn, which leads to oil dripping when the fuel injector stops injecting fuel, which causes the nozzle to burn and deposit carbon, leading to jamming failure. ④ The jet buckling pressure is too low, which leads to the high-pressure gas passing through the combustion chamber; ⑤ When the fuel injector is installed, the gasket is missing or damaged, which leads to air leakage, causing the local temperature of the fuel injector to be too high and stuck. ⑥ The manufacturing reasons of parts, such as too tight fit between the injector mounting hole on the cylinder head and the injector, too small clearance between the needle valve body and the mounting hole on the cylinder head, and too deep machining of the injector mounting hole on the cylinder head.

Second, the repair method of nozzle sticking: first put the stuck nozzle into diesel oil or engine oil to heat it, then take it out and wrap it with cloth, then clamp the needle valve with pliers and move it slowly, and take it out of the needle valve body. Drop a small amount of clean engine oil into the needle valve body to make the needle valve move repeatedly in the needle valve body until the needle valve can move freely in the needle valve body. If there are burn marks on the sealing surface of the needle valve, it should be polished with grinding paste. Pay attention to the amount of grinding paste and grinding time when grinding. Install the cleaned clock valve pair on the syringe and adjust the injection pressure before reuse.