What Should the Engine Idle Speed Be?
2 Answers
Engine idle speed should be between 500 and 800 revolutions per minute. An engine is a machine capable of converting other forms of energy into mechanical energy, suitable for power generation devices. Based on structural functions, engines are categorized into: 1. External combustion engine: Fuel burns outside the engine; 2. Internal combustion engine: Fuel burns inside the engine; 3. Gas turbine: Combustion produces high-pressure gas, which is used to drive the turbine blades to rotate and output power. Methods for engine maintenance include: 1. Regularly change the engine oil and oil filter; 2. Maintain good ventilation in the crankcase; 3. Periodically clean the fuel system; 4. Regularly clean the radiator; 5. Periodically clean the crankcase.
I've driven many cars and found that the ideal engine idle speed generally falls between 700 to 900 RPM. My old Jeep idled at 800 RPM, running smoothly without shaking; most new cars maintain around 750 RPM, keeping the engine quiet and fuel-efficient. During cold starts, the idle might surge to 1200 RPM but will drop back to normal range once warmed up. If the idle drops below 600 RPM, the engine may stall easily, possibly indicating a dirty throttle body or clogged air filter. An excessively high idle speed (over 1000 RPM) not only wastes fuel but could also signal sensor malfunctions or fuel system issues. During daily driving, I simply monitor the tachometer—a steady needle means everything's fine. Regular maintenance, like cleaning the throttle body, ensures stable idle speeds and extends engine life.