A new 1300km landscape with a mileage of only 1300km, with a M4R engine and a transmission. User response: when the vehicle starts and flameout, it has a "glare" sound, and the higher the engine speed is, the more obvious the abnormal noise is. After receiving the car: after trial run, it was found that there was a real noise when the vehicle started and stalled, and the engine speed increased, and the abnormal noise increased obviously. Using the fault diagnosis instrument to read the data flow, it is found that all the data in the idle, medium speed and high speed conditions are in the normal range, the engine can operate normally after the engine start, and the engine fault light is not lit. Refer to the maintenance information of Renault new scenic car, check engine and accessories. First, the generator drive belt is dismantled and the test is started, and the noise still exists, which excludes the faults of the generator, the tightening wheel, the inert wheel and the transmission wheel of the air conditioner compressor, and further judges that the sound is sent out of the engine. After the right front wheel is removed, the number of the engine crankshaft is rotated, the rotation is smooth, no abnormal resistance is found, and the crankshaft works normally. According to the maintenance data, the engine oil pressure is measured to determine whether the internal oil passage of the engine is blocked. Starting the vehicle idle speed 15min, connecting the fault diagnosis instrument, observing the change of the temperature of the engine cooling fluid in the data flow. When the coolant temperature reaches 85 C, the oil pressure measuring tool is connected with the oil pressure of 1.5 bar (1bar=100 kPa) at idle speed, and the engine speed is 2000 R /min when the oil pressure is about 4bar, all of which are normal. All the oil is released and removed from the oil bottom. It is found that the oil is the normal color, and there is a trace iron chip. It is also in the normal range. Therefore, the engine's operation and performance are judged well. After careful speculation, it should be the distinct noise when starting, and the abnormal noise comes from the starter. First, the starting machine is removed and checked. It is found that the gear rotation and tooth condition are all normal, without any abnormal, and then the condition of the flywheel is checked by rotating the crankshaft, and there is no tooth and bad tooth on the flywheel. There is no abnormal wear, so the trouble of starter and flywheel is excluded. But when rotating the crankshaft, unintentionally found the "clicking" sound of the flywheel, after careful examination, the 4 bolts connecting the flywheel and the hydraulic torque converter were not completely tightened, causing a channeling between the flywheel and the hydraulic torque converter, the impact bolt produced the abnormal sound, and the 4 bolts connecting the flywheel and the hydraulic torque converter were in accordance with the rules. After the torque is tightened and the starter is installed, the abnormal noise is eliminated. The fault diagnosis instrument is used to check the engine running data, which is all in line with the requirements and troubleshooting.