The failure that the engine cannot be started is shown as follows: the starter can drive the engine, and the running speed can gradually increase when starting, but the engine will automatically shut down before reaching the normal speed, and the engine will reverse.

1. Check the fuel injection pump connection device and fuel injection timing
Start the motor and check whether the input shaft of the fuel injection pump rotates and whether the coupling is reliably connected. If it does not rotate or rotates too slowly, check whether the coupling is broken, whether the semicircle keys of the driving and driven plates are intact, and whether the fixing screws are loose.
If all the above items are normal, check whether the fuel injection is timed again by removing the high-pressure fuel pipe of the first cylinder, turning the crankshaft to make the piston of the first cylinder at the starting point of the expansion stroke. At this time, the pointer of the flywheel housing should be aligned with the 0 degree line on the flywheel (if the side cover plate of the fuel injection pump is removed, the plunger spring of the first cylinder should be in a compressed state); Reverse the crankshaft according to the running direction of the diesel engine, so that the pointer on the inspection window is aligned with 15~25 degrees on the flywheel (equivalent to the specified angle value of the injection advance angle); Loosen the two fastening screws on the driving and driven plates of the drive shaft coupling of the fuel injection pump, and slowly and evenly rotate the camshaft of the fuel injection pump to the oil outlet of the first cylinder according to the rotation direction of the fuel injection pump until the oil level just fluctuates; Tighten the two screws on the driving and driven plates of the coupling.

2. Check the low pressure oil circuit
First, check the diesel tank. If the switch can be opened and there is enough fuel in the tank, check whether the tank vent is blocked; If it is smooth, check whether there is water or impurities at the bottom of the oil tank.
Secondly, check whether the oil circuit is smooth. If the oil tank is in normal condition, the pump oil test can be conducted through the manual pump. If there is no suction when pulling out the button, but it is hard when pressing the button, it indicates that the oil path between the fuel transfer pump and the fuel injection pump is blocked. Check whether the diesel filter is blocked; If it is obviously hard to pull out the button, and the button returns automatically after releasing, it indicates that the oil path between the oil tank and the oil transfer pump is blocked. Check whether the oil pipe is blocked first. If there is no normal oil pumping resistance when pulling up and pressing down the button, it indicates that the hand oil pump is faulty. First check whether the oil delivery valve of the oil delivery pump is stuck or unsealed; Disassemble the oil delivery pump to see if the spring is broken or the piston is damaged; If the environment is cold, check whether the diesel used is waxed at the ambient temperature.
Again, check whether there is air in the oil circuit. If the oil circuit is unblocked, check whether there is air in the oil circuit, that is, release the exhaust plug on the diesel filter or fuel injection pump, and pump the oil manually. If there are bubbles in the diesel oil flowing out of the exhaust plug (that is, foam diesel oil flowing out), it means that there is air entering the oil circuit. First check whether the oil pipe is damaged and whether the pipe joint is loose.
If there is no damage or looseness, the air release inspection shall be carried out by sections. The inspection method is: unscrew the oil outlet connector on the oil transfer pump, press the manual pump, and observe the diesel oil discharge. If the foam diesel cannot be discharged completely, it means that the oil pipe between the oil transfer pump and the oil tank or the oil inlet pipe in the oil tank is broken or the pipe joint is loose; If the foam diesel can be drained, loosen the diesel filter output connector or the exhaust plug, and then conduct the exhaust test to check whether the pipeline and connector leak.
The failure to start the engine is a very annoying problem. After all, if the whole machine cannot run, our goal cannot be achieved. Therefore, it is important to prevent problems before they occur, and daily inspection is particularly important.