关键词: 发动机；高职国赛；迈腾 B8L；无法启动；典型部件；故障诊断；故障排除

Abstract: Taking the Magotan B8L selected for the "Automobile Troubleshooting" of the vocational national competition as the object, diagnosis and troubleshooting of typical component damage in the electrical system that causes the engine to fail to start. Firstly, the fault phenomena of the engine being unable to start are described: the entire vehicle is not powered on, the starter is not running, and the starter is not running, etc. Secondly, introduce the startup strategy of the Magotan B8L: vehicle power on strategy and starter operation strategy. Once again, select the failure to power on caused by damage to the ignition switch, failure of the starter due to damage to the power bus, the failure to operate the starter caused by damage to the starting relay and its circuit, and the failure to start the vehicle caused by damage to the crankshaft position sensor and its circuit. Finally, the faults of the ignition switch, power bus, start relay and its circuit, crankshaft position sensor and its circuit are diagnosed and eliminated. Without the use of a fault diagnosis instrument, a systematic, comprehensive, and effective troubleshooting method is provided for the failure of the engine to start caused by the damage to the four major components mentioned above. It also provides a detailed reference basis for diagnosing and troubleshooting other components.

Key words: Engine; Higher vocational national competition; Magotan B8L; Unable to start; Typical components; Fault diagnosis; Fault exclude