(1) The wear of the fuel injection pump causes diesel oil to enter the engine oil. This fault is manifested as follows: the engine oil level is significantly higher, accompanied by diesel smell, and in serious cases, oil emerges from the oil filler or vent hole. For piston fuel transfer pump, there are only two ways for diesel oil to enter the oil: diesel oil can enter the lubricating oil in the lower chamber of the fuel injection pump directly from the side gap of the roller body of the fuel transfer pump.
The wear of the plunger coupling of the fuel injection pump slave cylinder exceeds the limit, which causes the internal leakage of the slave cylinder (which will affect the normal start of the engine in serious cases), and the diesel oil from the internal leakage will flow into the lubricating oil in the lower chamber.
The solution is to open the side cover of the fuel injection pump and start the engine. If diesel oil spills out of the plunger of the slave pump, it means that the wear of the plunger coupling of the slave pump is out of limit. The plunger coupling needs to be replaced and the fuel injection pump should be calibrated on the test bench. Remove the oil transfer pump (without removing the connecting oil pipe) and pump the oil by hand. If diesel oil emerges from the side gap of the oil transfer pump roller, it is proved that the oil transfer pump is faulty. You can also remove the oil transfer pump and all connecting oil pipes, tighten the hand oil pump, block the oil outlet of the oil transfer pump, and introduce gas with a pressure of 0.4MPa from its oil inlet. If there is gas emerging from the side gap of the roller, it indicates that the oil transfer pump is faulty and should be replaced.

(2) The reason for oil leakage at the high-pressure oil pipe joint at the oil outlet of the white fuel injection pump is that the concave oil outlet of the fuel injection pump and the convex high-pressure oil pipe joint are not sealed tightly due to wear and tear. The solution is to pad the concave joint at the oil outlet of the fuel injection pump in each pump factory and give it free of charge along with the pump. This method can also be used for oil leakage at the connection between the fuel injector and the high-pressure oil pipe. The practice has proved that the effect is very good.

(3) If the four fine-tooth bolts of the fuel injection pump are not tightened, the loose pump and pump base will dry wear when the engine is working, and then there will be a gap. The longer the time is, the larger the gap will be, and finally the fuel injection pump installation position will be displaced. The fuel injection pump and the transmission shaft are not concentric, and the shaft will be broken.
The solution is to use a proper thickness of red copper sheet as a pad between the pump and the pump base to eliminate the gap. When reassembling the fuel injection pump, clean the threaded hole first, then tighten the four fixing bolts to the specified torque, and check the coaxiality of the fuel injection pump shaft and the transmission shaft. If it does not meet the standard, readjust it. It is recommended to remove the fuel injection pump together with the pump base.