(1) Diesel fuel entering the engine oil due to fuel pump wear: The engine oil level rises significantly and is accompanied by a diesel fuel smell. In severe cases, oil leaks out from the oil filler or vent. For piston-type fuel pumps, diesel fuel can enter the engine oil in only two ways: diesel fuel can directly enter the lubricating oil in the lower chamber of the fuel pump through the side clearance of the fuel pump roller body; or the fuel pump slave plunger assembly is worn beyond the limit, causing internal leakage of the slave pump, and the leaked diesel fuel will flow into the lubricating oil. Remedial measures: Open the side cover of the fuel pump and start the engine. If diesel fuel splashes out from the slave plunger, it indicates that the slave plunger assembly is worn beyond the limit and the plunger assembly needs to be replaced. The fuel pump should be calibrated on a test bench. Remove the fuel pump and pump oil with a hand pump. If diesel fuel leaks out from the side clearance of the fuel pump roller, it proves that the fuel pump is faulty. Alternatively, the fuel pump and all connecting oil pipes can be removed, the hand pump tightened, and the fuel pump outlet blocked. Gas at a pressure of 0.4 MPa can be introduced through its inlet. If gas escapes from the roller side gap, it indicates a malfunction in the fuel pump, and it should be replaced.
(2) Oil leakage at the connection between the fuel injection pump outlet and the high-pressure connection: Oil leakage occurs due to wear at the concave outlet of the fuel injection pump and the convex high-pressure connection, resulting in a poor seal. Solution: Simply add a concave round copper gasket to the concave connector of the fuel injection pump outlet. This type of gasket is available at various pump calibration factories and can be given away free of charge with pump calibration. This method can also be used for oil leakage at the connection between the injector and the high-pressure oil pipe, and practice has proven its effectiveness.
(3) (3) Fuel injection pump shaft breakage: If the four fine-threaded bolts of the fuel injection pump are not tightened, the loose pump will rub against the pump seat during engine operation, leading to a larger gap. This will eventually cause the fuel injection pump to shift, resulting in misalignment between the pump and the drive shaft, ultimately causing the shaft to break. Remedy: Use a piece of copper sheet of appropriate thickness as a shim between the pump and the pump seat to eliminate the gap. When reinstalling the fuel injection pump, first clean the threaded holes, then tighten the four fixing bolts to the specified torque, and check the coaxiality of the fuel injection pump shaft and the drive shaft. If it does not meet the standard, it should be readjusted. It is recommended that the pump seat be removed together with the fuel injection pump when disassembling it.
