What Causes the Engine to Stall When Idling with AC On?
2 Answers
The reason for the engine stalling when idling with the AC on is generally due to a malfunction in the throttle idle control system. Here are the specific details: Cause: Automatic stalling during idle is mostly caused by issues with the throttle valve or idle control valve. Severe carbon buildup or component damage in the throttle valve or idle control valve can trigger this fault, with insufficient air intake being the primary cause. Throttle Valve Introduction: The throttle valve is a controllable valve that regulates the air entering the engine. After the air enters the intake manifold, it mixes with gasoline to form a combustible mixture, which then burns to produce power. It connects to the air filter at the top and the engine block at the bottom, and is often referred to as the throat of the car engine.
I've been driving a taxi for over a decade and often encounter stalling issues when idling with AC on. This is mostly because the engine load suddenly increases - when the AC compressor kicks in, it's like asking the engine to pull an extra heavy load. There are three common causes: First, severe carbon buildup where the throttle body and fuel injectors are coated with sludge, restricting air intake; Second, ignition system problems like worn spark plugs or leaking ignition coils resulting in insufficient spark energy; Third, inadequate fuel supply from the fuel pump, especially noticeable in older cars with worn pumps. Once my car had this issue, and it improved significantly after cleaning the throttle body. It's important to avoid prolonged idling with AC on - it harms the engine and wastes fuel. Regular maintenance is crucial.
