What Causes Unstable Idle Speed When the Atenza's Air Conditioning is On?
3 Answers
Atenza's unstable idle speed when the air conditioning is on is mainly because the compressor starts working when the air conditioning is activated. Since the compressor is driven by the engine, its operation increases the engine's load. Solutions include: 1. Cleaning the throttle body, fuel injectors, and spark plugs. 2. Checking whether the generator provides stable power supply. Here is some additional information about the Atenza: The Atenza is a new-generation mid-to-high-end sports sedan flagship model developed by Mazda with a spirit of breaking conventions and starting from scratch. The Atenza continues the design of the imported Mazda ATENZA. The new Mazda Atenza has undergone significant upgrades in terms of exterior and interior design, material quality, and driving comfort. In terms of power, it complies with the China VI emission standards, with output data consistent with the current model, and is equipped with a 6-speed automatic transmission.
I've encountered many Mazda Atenza owners complaining about unstable idling when the air conditioning is on, which is indeed quite annoying. Possible causes include a sudden increase in engine load: when the AC compressor kicks in, it demands extra power, and if the idle control system can't keep up, it can cause the RPM to fluctuate. I recommend first checking the idle control valve—if it's dirty or stuck, it can easily cause issues. Another possibility is a vacuum leak: connections in the AC system might lead to vacuum leaks, affecting smooth engine operation. Worn-out spark plugs can also contribute, especially when the AC increases the load; weak ignition can lead to rough idling. Weak battery or alternator: insufficient voltage can cause the compressor to malfunction, affecting the entire system. When driving such cars, I always remind friends to regularly clean the throttle body and fuel injectors to prevent carbon buildup, and to check if the compressor belt is worn or loose—too tight or too loose can disrupt balance. If the issue persists, it's best to seek professional diagnosis promptly to prevent the problem from worsening.
I remember my own Mazda6 (Atenza) also experienced unstable idle speed when the AC was turned on. That day while waiting at a traffic light, the engine started shaking as soon as the AC was activated, like an unstable racing heartbeat. After some troubleshooting, I found the main culprit was the idle speed control system issue: when the compressor starts, the sudden load increase can't be properly adjusted if the sensors malfunction or wiring becomes loose. Another common point is the fuel system: dirty fuel injectors can't deliver the extra fuel needed for AC operation, leading to unbalanced air-fuel mixture. I also checked the AC refrigerant pressure: both excessively high and low pressures affect compressor load, making the engine struggle. Some simple self-checks I recommend: first turn off the AC to see if idle stabilizes; try cleaning the air filter as clogged intake makes response sluggish; listen for abnormal engine sounds like vacuum leaks. Ultimately, replacing the idle air control valve solved my problem, but remember to maintain these components regularly.
