What are the causes of excessively high engine idle speed?
2 Answers
Engine idle speed being excessively high can be caused by: 1. Faults in the coolant temperature sensor, throttle position sensor, idle control valve, or fuel injector; 2. Throttle sticking or not closing properly; 3. Air leaks in the intake system. Solutions for excessively high engine idle speed include: 1. Cleaning or replacing the idle control valve and using a specialized decoder to perform a basic idle speed setting; 2. Cleaning and inspecting the fuel injector's spray volume to ensure there are no blockages or leaks; 3. Adjusting or replacing the throttle position sensor. The impacts of excessively high engine idle speed are: 1. Increased fuel consumption; 2. Damage to the clutch friction plate; 3. Increased vehicle noise.
As an experienced driver, I've driven many cars and encountered high engine idle speed quite often. The most common causes are a dirty or stuck throttle valve that isn't moving smoothly, leading to air leaks in the intake pipe, or the idle control valve being clogged with sludge, disrupting air intake. Another issue could be a faulty idle speed sensor, which is supposed to regulate engine speed—if it malfunctions, the RPM fluctuates erratically. Additionally, problems in the ignition system, such as aging spark plugs, or leaking fuel injectors that disrupt the fuel mixture can cause the idle speed to spike. Ignoring this issue can lead to increased fuel consumption, excessive emissions, and even engine damage over time. It's recommended to check the throttle valve every six months and use high-quality engine oil as a preventive measure. In short, if you notice any problems, take your car to a professional repair shop as soon as possible—don't try to fix it yourself to save money, as safety should always come first.
