Experience sharing of manual experience diagnosis method for automobile fault maintenance

The manual experience diagnosis method of automobile fault refers to the diagnosis method that the diagnosis personnel use rich practical experience and certain theoretical knowledge to check, test, analyze and judge the causes and parts of automobile fault through simple inspection means such as eyes, ears, hands and nose. Manual experience diagnosis is the traditional and basic method of automobile fault diagnosis. Even with the rapid development of modern instrument diagnosis technology, it can't replace manual experience diagnosis. First, observing "seeing" with eyes means observing various parts of the car with eyes or magnifying glasses and endoscopes, looking for clues to diagnose faults. Mainly includes the following items and parts: 1. Display of automobile fault indicator lamp, instrument, alarm lamp and indicator lamp. 2. Whether the exhaust color of the engine is normal. 3. Whether the liquid fluidity is normal, and whether the colors and liquid levels of various liquids are normal. 4. Whether some actions are normal and whether the connection parts are loose, cracked, deformed or broken. 5. Whether the line is damaged, loose or broken; Whether the wire terminal is corroded or deformed. 6. Whether the oil pipe and gas pipe are squeezed, bent, damaged or broken. 7. Whether all joysticks, cables and pull rods are adjusted correctly. 8. Whether there is coking in the intake pipe, intake and exhaust valves and cylinders. 9. Tire pressure and tire wear, whether related parts are deformed, and whether the fender is scratched. 2. Touch refers to detecting machine parts by sensing temperature, pressure and vibration, so as to obtain fault information. Mainly includes the following items and parts: 1. Whether the engine water temperature and automatic transmission oil temperature are abnormal. 2. Some faults such as air conditioning system, automobile suspension system and shock absorber. 3. Touch whether the plug of the line and the connector of the wire are loose and have poor contact. 4. Touch the vibration of the fuel injector, motor and other parts to determine whether it works. 5. Touch the ignition module, ignition coil, relay and other electronic components to determine whether they are working normally. 6. Check the tightness of the belt to determine whether it slips. 7. Touch the generator, air conditioner compressor and other parts to determine whether there is any loose connection. 8. Feel the viscosity and impurities of the oil to judge the oil quality and possible faults. 9. Feel the pressure fluctuation of cooling water pipe and fuel pipe, and understand the cooling water circulation and oil supply. 10. Check the wear of the friction surface, check the fit clearance of the friction pair and the smooth operation of the rotating parts. Third, listening to the sound with your ears "Listening" means listening to the sound emitted by the car with your ears or stethoscope, judging the location and type of the fault and helping to find the cause of the fault. Mainly includes the following items and parts: 1. Abnormal sound of intake and exhaust system. 2. Abnormal noise caused by belt slipping. 3. Abnormal noise of generators, air-conditioning compressors and other components. 4. Abnormal sound of engine and mechanical transmission. 5. The ignition system high voltage line leakage. 6. Working conditions of relays, solenoid valves, etc. 7. Abnormal sound of steering system and braking system. 8. Abnormal sound of automobile suspension, body and wheels. 4. Smell the smell with the nose "Smell" is to perceive the abnormal smell produced by various parts of the car through the nose, which is helpful for diagnosing faults or projects. Mainly includes the following items and parts: 1. Judging the working condition of the engine by the smell of the exhaust gas discharged by the engine. 2. Judging the quality of oil and the working conditions of related parts by the peculiar smell of oil such as engine oil and automatic transmission oil. 3. Judging clutch slippage and slow braking by the smell of burning nonmetallic materials. 4. Look for faults such as overheating and short circuit of wires through the smell emitted by rubber and plastic parts. The above is the specific operation content of the manual experience diagnosis method of automobile fault. Although these methods are simple, they are indispensable basic methods for automobile fault diagnosis.