Failure phenomenon:

A Isuzu car with a mileage of about 16,000 KM suddenly turned itself off during driving. During the parking check, no diesel fuel was found in the fuel injection pump. When the oil in the fuel injection pump is removed by the oil pump, the engine can be started, but the car only travels about 200 meters, and the engine turns off itself. When the oil inlet pipe on the fuel injection pump is removed, a smoke is generated from the pump chamber.

According to the above phenomenon,

Initially determine that there is a problem with the fuel system. The engine is equipped with a single-piston distributed VE fuel injection pump, which is removed and installed on the fuel injection pump test bench. When the oil pump switch on the test bench is turned on, 0.002 megahertz of low-pressure diesel oil enters the fuel injection pump. At this time, it was found that there was diesel fuel at the valve seat of the first cylinder of the fuel injection pump, indicating that the oil outlet valve of the cylinder was not tightly sealed (the valve seat was tightened at this time). For the first cylinder injector test, the injection pressure was extremely low, and the disassembly was checked, and the needle valve was found to be stuck in the open position.

Troubleshooting:

The injector needle valve is repaired, tested and adjusted by the injector tester, and the injection pressure and atomization quality meet the requirements; the fuel injection pump outlet valve is ground so that the first cylinder outlet valve no longer leaks oil. The repaired injector and fuel injection pump are mounted on the engine, and after repeated trials, the engine no longer extinguishes itself.

Failure analysis:

Since the fuel injection valve of the first cylinder of the fuel injection pump is not tightly sealed, when the needle injector of the fuel injector is stuck in the open position, the high pressure gas in the cylinder will enter through the injector, the high pressure oil pipe and the oil discharge valve. In the fuel injection pump, a large amount of gas is infiltrated into the fuel and the oil supply is interrupted, and the engine is automatically turned off.