What Causes the Idle Speed to Increase When Engaging Gear?
1 Answers
Introduction to the causes of increased idle speed when engaging gear: Malfunction of the idle control valve: Normally, electronic fuel injection engines rely on the idle control valve to determine the normal idle speed. During driving, the electronic control unit (ECU) calculates based on the information transmitted by the engine to adjust the intake air volume, thereby altering the engine's idle speed. However, if oil contamination or carbon deposits affect the idle control valve, the ECU cannot receive accurate information, leading to improper idle speed regulation and resulting in excessively high idle speed. You can check whether the idle control valve makes any sound during operation; if there is no sound, it indicates a malfunction. Intake system leakage: Maintaining normal idle speed requires strict control of the intake air volume. When there is a leak in the intake system, the ECU cannot perform accurate calculations, leading to an increase in intake air volume. In such cases, the idle speed will also be excessively high. Fuel injector leakage or clogging: When the fuel injector leaks or becomes clogged, it causes issues in the vehicle's fuel injection system, resulting in either excessively high or low concentration of the air-fuel mixture inside the engine. This inevitably affects the cylinder's operation, leading to unstable idle speed.
