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What Are The 6 Main Leaks Of Diesel Generator Fuel Injection Pumps

Aug. 29, 2021

Fuel injection pump is a key component of the fuel system of diesel generator sets. The internal leakage of the fuel injection pump is generally difficult to see with the naked eye. When it is found that the diesel generator is difficult to start, the power drops, and there is no gas in the oil circuit, it will sometimes automatically turn off, and at the same time, the fuel injection pump casing or oil pan is abnormally raised, which can be diagnosed as an internal leakage of the fuel injection pump. The 6 main leakage locations of the generator fuel injection pump are as follows:


1. Leakage at the installation shoulder of the plunger sleeve. There is no sealing gasket between the large cylindrical shoulder of the plunger sleeve of the piston fuel injection pump and the upper body of the pump, and the sealing is achieved by the fine processing of the two joint surfaces. It is a ring-shaped, extremely small sealing surface. The obvious squeeze marks that appear at this time will cause a large amount of diesel to leak, making the diesel engine unable to work normally, and sometimes it can barely run at low speeds, but air will be sucked in after the speed increases. The main reason for the squeeze marks on the shoulder of the piston sleeve is that the torque of the oil pressure regulator seat is too large. The fluctuating stress of the high pressure diesel oil during operation will also accelerate the fatigue strain.


2. Leakage problem between plunger and plunger sleeve gap. The fit between the piston and the plunger sleeve is inherently precise, with a gap of only 0.002 to 0.003 mm. If selected and ground, its surface roughness accuracy is very high. During work, if the diesel contains impurities and moisture, it will cause wear or corrosion of the plunger and coupling parts, increase the gap, and leak the diesel, which cannot cause high pressure on the diesel.


3. The screw for the plunger sleeve is leaking oil. There is a pure copper cushion under the plunger sleeve positioning screw, the main function is to seal. If this small gasket installation leaks or becomes fluffy or breaks, the diesel in the plunger sleeve will leak from the set screw.


diesel engine

4. The delivery valve leaks. When the pure copper (or nylon) gasket between the high-pressure oil cavity on the oil outlet valve and the large end surface of the oil outlet valve seat is broken or deformed, or the oil outlet valve seat is not tightened, the high-pressure oil cavity on the oil outlet valve is connected with the low-pressure oil cavity below, causing the fuel injection pump of the generator to be unable to produce high-pressure diesel.


5. The leakage problem of the oil return overflow valve. The multi-cylinder fuel injection pump is equipped with an oil return overflow valve, its function is to keep the diesel pressure of the upper body horizontal oil passage of the fuel injection pump above 150kPa. For example, if the oil return overflow valve and valve seat are worn, rusted, there is garbage on the door, or there is oil return phenomenon, reduce the diesel pressure of the plunger inlet port, draw air into the fuel injection pump, and make the diesel engine unable to work and automatically extinguish the flame.


6. Oil leakage between the push rod of the oil transfer pump and the casing. If the plunger-type oil transfer pump push rod and shaft sleeve wear too much or the push rod sealing ring is damaged, the oil displacement will be greatly increased. If the drain hole is blocked, this part of diesel will flow into the fuel passage of the fuel injection pump.


The leakage of the fuel injection pump of the diesel generator seems to be small, but it is actually very harmful. For diesel engine fuel injection pump leakage failure, as long as you master the search method, it is not difficult to determine the fault location, and can detect the fuel pump leakage, you can use the above solutions for the fault location, and basically solve this type of failure. For more details, please contact us with sales@dieselgeneratortech.com

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