What Causes Idle Stalling?
2 Answers
Reasons for idle stalling: 1. Damage to the engine idle control valve or its wiring; 2. Leakage in the vacuum pipe of the brake vacuum booster; 3. Damage to the diaphragm of the brake vacuum booster; 4. Air leakage in the intake manifold; 5. Issues with the idle control module in the engine electronic control unit. The idle performance of an engine significantly impacts emissions, fuel consumption, and comfort, making it an important indicator for evaluating engine performance. During idle, the engine is disconnected from the transmission system with the throttle pedal fully released, operating only against its own resistance without any external power output. The engine speed during idle is called the idle speed, which should not be too high or too low. Excessively high idle speed increases fuel consumption, while excessively low idle speed causes unstable engine operation.
Idle stalling refers to the situation where the car suddenly shuts off while waiting at a red light or during low-speed operation. This issue is quite common, let me explain. The main culprit is carbon buildup in the throttle body, which blocks air intake and causes the engine to lose power. Aging spark plugs are also to blame, as poor ignition becomes particularly noticeable at low speeds. Fuel system problems like a weak fuel pump or clogged injectors leading to insufficient fuel supply are common causes too. Don't forget the idle control valve - when dirty or malfunctioning, it causes unstable regulation. Over the years, I've seen many cases where minor issues escalate into major problems, like burned valves due to neglect. Regular maintenance is key: clean the throttle body periodically, replace spark plugs every 1-2 years, and if stalling occurs frequently, get the wiring and sensors checked promptly at a shop. Never take this lightly - driving safety comes first.
