How to Deal with High Idle Speed When the Air Conditioner is On?
3 Answers
First, adjust the idle speed. If the problem persists after adjustment, check whether the idle jet and idle air jet are clogged. If the air jet is clogged, clean it with gasoline or acetone and blow it through with compressed air. If the jets are not clogged, stabilize the engine speed at a certain level and listen for air leaks at the intake manifold or the middle and lower gaskets of the carburetor. If there is an air leak, it can be fixed by tightening the screws or adding/subtracting shims. Repair and adjustment should be performed.
Last time when I turned on the AC in my car, the idle speed suddenly increased and the tachometer jumped sharply, which gave me a scare. After checking online resources, it might be due to the high load of the AC compressor triggering an incorrect response from the idle speed control system. I did some DIY checks: first, I turned off the AC to see if the idle speed returned to normal—if it did, it indicated the issue was related to the AC; then, I opened the engine compartment to check if the idle control valve had carbon buildup or was stuck; if cleaning didn’t help, I inspected the vacuum lines for leaks using soapy water. It turned out there was a small crack in a vacuum hose, and replacing it fixed the problem. I recommend regular maintenance and cleaning of related components to avoid similar failures caused by carbon buildup—it saves money and ensures safety. Before working, make sure the engine is off and avoid operating with live electrical components.
I've encountered the issue of high idle speed when the AC is turned on in my car. There are many possible causes, but the common ones are a faulty idle control device or a vacuum system leak. The compressor requires more power to start, and the engine should smoothly adjust the RPM, but a clogged control valve or sensor misreading can cause the RPM to surge. The troubleshooting steps include: starting the car to observe idle speed; turning on the AC to confirm the abnormality; using a diagnostic tool to read fault codes first; checking and cleaning the idle motor and throttle body; inspecting vacuum hose connections for looseness. If DIY doesn't work, take it to the repair shop promptly to avoid increased fuel consumption and engine wear. Regular warm-up before driving and routine maintenance can help prevent this issue.