Judgment method of fuel pump failure:
1. Turn on the ignition switch, do not start the engine, you can hear the petrol pump working for 12 seconds, you can judge whether the petrol pump is working;
2. It can be heard in the cab, and a sound similar to "hiss" is made at the same time the switch starts. However, if there is a problem with the fuel pump, it should not burn the car;
3. Unplug the oil pump relay, connect the oil pump circuit with a dedicated jumper, turn on the ignition switch, and do not start the engine, the oil pump can work, indicating that the oil pump is normal;
4. Connect the oil pressure gauge to see if the engine can build up the oil pressure of about 250KPa, and if the oil pressure builds up quickly, if the oil pressure can be established normally, the oil pump can work;
5. Then turn off the engine ignition switch to see if the oil pressure is quickly discharged and the oil pressure drops quickly to determine whether the pressure relief valve of the oil pump is normal. The normal oil pressure can be maintained so that the engine can start normally next time.