During the working process of the diesel engine, due to improper use and maintenance, some parts will fail, and the speed will decrease and self-extinguishment will occur. According to the degree of urgency and exhaust smoke of quenching welding speed, the main parts and causes of the failure can be determined. First, when the flame is turned off, the rotation speed is gradually reduced, and there is no abnormal change in the sound and color of the diesel engine. This failure occurs in the fuel system. According to the principle of easy first and then difficult, first check whether there is fuel in the fuel tank, and whether the fuel tank ventilation hole is blocked. If there is no oil in the fuel tank, it cannot be supplied, the vent hole is blocked, and negative pressure is formed in the oil table, so the oil supply is not smooth. If there is no such problem, check from the low pressure oil line to the high pressure oil line step by step to see if the oil line is clogged with debris and if it enters air. Failure of the high-pressure oil circuit, for a single-cylinder machine, mostly fuel injection pump can not supply high-pressure oil or injector needle valve is stuck; For multiple cylinder machine, most of the power transmission in the pump out In some cases, such as the transmission gear roller keys, the flower keyboard fixing screws are detached or broken, and the axles are broken. Second, the flame speed at the time of flameout is unstable, and the exhaust pipe emits white smoke. The reason for this failure is that there is water in the diesel. If the exhaust pipe still emits white smoke and extinguishes after the water in the oil is removed, there is a possibility that the cylinder head pad is burned and connected with the water channel, resulting in water in the cylinder. If the cylinder mat is in good condition, the cylinder liner may be cracked or broken, or the cylinder head may have cracks and communicate with the water channel, and the cooling water enters the cylinder. Because of the water in the cylinder, the temperature of the air-fuel mixture is reduced and it cannot be extinguished naturally. Third, when the flame is turned off, the rotation speed gradually decreases, and the exhaust pipe emits smoke. The causes of this failure are: diesel engine is seriously overloaded, or the fuel supply is too late, the intake air is insufficient (the intake pipe is blocked, or the intake valve clearance is too large, the gas distribution wheel is excessively worn, etc.), and the mixture is too concentrated. This failure caused by complete combustion is often a combination of several reasons, so when troubleshooting, one item should be analyzed and checked. Fourth, when the flameout, the sharp decline in speed, black smoke exhaust pipe causes such failures There are two main reasons: First, the main oil pressure is not enough oil (oil sump oil, oil valve stuck in the starting position, oil pump Without oil or engine oil deterioration, etc., so that the surface of the crankshaft and bearing lubricate poorly, resulting in burning tile holding shaft, so that the engine is forced to turn off; Second, when replacing the piston, cylinder liner, the gap between the two is too small, the engine is After work, the piston is thermally expanded and the movement in the cylinder is hindered, causing the engine to stall. 5. When the engine is off, the engine power suddenly drops, the speed drops sharply, and abnormal sounds accompany it. The main causes of this failure are: broken crankshaft or piston pin; breakage of connecting rod bolt or loose nut; valve spring breakage or valve rod end folded into. The inspection should be carefully conducted to find out the specific cause of the failure and eliminate it. The engine may not be restarted until the cause of the failure is identified and removed.