What is the typical idle speed when starting a sedan?

[Rodrigues]

The idle speed for a sedan with a four-cylinder engine is generally around 800 RPM, while for six-cylinder and above models, it is approximately 600 RPM. However, the idle speed is not fixed and can vary depending on factors such as engine temperature and load. For example, when the engine temperature is low, the RPM may increase to ensure smooth operation and to quickly reach the optimal working temperature. As the engine warms up, the idle speed gradually returns to the normal value. An engine is a machine that converts other forms of energy into mechanical energy. Solutions for excessively high RPM include: 1. Adjusting the throttle opening; 2. Replacing the fuel injector, air conditioning clutch, engine, or transmission; 3. Adjusting the intake system; 4. Adding the appropriate engine oil.

[KarterRose]

When it comes to idle speed during car startup, it generally refers to the engine speed during a cold start, typically around 1000 to 1500 RPM. This is because the engine needs more fuel to warm up in low temperatures. I remember driving several sedans, whether in winter or summer, where I could see the tachometer jump up after ignition in the morning, and then gradually drop to the normal range of 700 to 800 RPM after two or three minutes. If you notice that the idle speed doesn’t drop, it might be due to a dirty air filter or carbon buildup in the throttle body, which needs cleaning. Temperature has a significant impact—higher idle speed in cold weather is normal, while it drops faster in warm weather. Long-term unstable idle speed can affect fuel consumption, so it’s recommended to regularly maintain and check spark plugs and engine oil to keep the engine healthy. Don’t rush to drive off after starting; wait for the RPM to stabilize before shifting into gear for safer driving.

[BrandonFitz]

From experience, it's common for sedan engines to idle above 1000 RPM at startup, especially when cold where it may reach up to 1500 RPM, then stabilize between 700-900 RPM after a few minutes. I've observed many vehicles during garage inspections - different models show variations: Japanese cars like Toyota/Honda quickly reduce idle speed after startup, while German models like Volkswagen may maintain higher RPMs, with turbocharged engines showing more idle fluctuation. Novices often worry high RPM indicates malfunction, but it's usually normal. However, if idle speed fluctuates wildly or the engine vibrates severely, check the oxygen sensor or vacuum leaks. Brief high idle at startup helps reduce wear - don't overconcern about temporary fuel consumption increase. If idle drops too low (below 600 RPM) with instability, it might indicate clogged fuel injectors.

[ORosalie]

The idle speed of a sedan during startup generally ranges between 1,200 to 1,500 RPM. As the engine temperature rises, it gradually drops to around 750 RPM for normal operation. This process is quite interesting, akin to a warm-up. It's normal for gasoline cars to have higher idle speeds during cold starts, while diesel cars may reach up to 2,000 RPM. Factors influencing this include ambient temperature, with more fluctuations in winter when the air conditioning is turned on. Regularly replacing the air filter can help maintain stable idle speeds. For safety, it's advisable to wait a bit after starting before driving.