汽车专业英语 教学课件 ppt 作者 廖忠诚 杨晓波 主编Chapter9 Service Procedure.pptVIP

Chapter 9 Service Procedure 9.1 Engine procedures 9.1.1 Checking Idle Speed Points to note 1. Checking the idle speed can only be done with a tachometer, which measures the engine revolutions per minute (rpm). 2.“Kicking” the throttle once the engine has warmed up will help allow the engine to settle into its normal idle condition. Note the reading again. Step-by-step instruction 1.Start the engine and note idle speed Switch on the ignition and start the engine from cold. Without revving the engine, note the rpm reading from the tachometer once it has stabilized and is running smoothly. 2.Rev the engine briefly and note speed again Allow the engine to warm up to its normal operating temperature, and note the idle speed again. Kick the throttle briefly to rev the engine and let it settle back to idle speed, and note any change in the tachometer reading. 3.Compare readings with specifications Compare your idle speed readings with the specifications in the vehicle workshop manual. If your readings are outside the acceptable range, this could indicate a problem in the air or fuel system. 9.1.2 Removing And Replacing A Cam Belt Points to note 1.The number of pulleys driven by the cam belt will differ from manufacturer to manufacturer. 2. Always follow manufacturers recommendations regarding cam belt change intervals and replacement procedures. 3.Cam belts should be kept in their packaging until required. They should be stored in an environment that has minimal humidity, consistent temperatures and is free from dust and oil contamination, 4.Do not bend, twist or crimp a cam belt. 4.If a cam belt is to be reused make sure it is refitted so it turns in the same direction as before. Some cam belts have directional arrows and aligning marks on their outer surface to assist with fitment and engine timing. Step-by-step instruction 1.Disconnect the battery Locate the battery and its negative terminal. Loosen the terminal clamp and remove the terminal from the battery po