(1) There is air in the oil circuit of the fuel system. Remove the air in the high pressure or low pressure oil pipe.
(2) The fuel injector parts are seized, regrind or replace
(3) The fuel supply of the fuel injection pump is abnormal. Find the cause according to the troubleshooting method of the fuel injection pump.
(4) Oil leakage from the high-pressure oil pipe. Tighten the nut and replace the oil pipe with cracks.
(5) Wear of fuel injector parts Replace or regrind
