What are the reasons for unstable idle speed after throttle cleaning?
3 Answers
Unstable idle speed after throttle cleaning may be due to the throttle opening not being reset. Relevant information about the car throttle is as follows: 1. Introduction: The throttle, as the name suggests, is a valve that regulates the amount of air. This valve is generally installed in the engine's intake tract. Above it is the car's air filter, and below it connects to the main body of the engine. Therefore, the throttle is vividly compared to the throat of the engine. It is worth noting that this valve is only used in gasoline engines and is not present in diesel engines. 2. Function: The throttle is a valve that can adjust the opening and closing size. Just like a faucet can regulate the flow of water, the throttle can also regulate the amount of air entering the engine. Air passes through the throttle into the combustion chamber inside the engine, where it mixes with fuel sprayed by the electronic injector to form combustible gas. The combustible gas burns inside the engine to perform work, thereby driving the car.
After cleaning the throttle body, unstable idle speed is a common issue I've encountered. The cause is usually improper installation of the throttle body itself, such as air leaks due to incorrect reassembly after cleaning, or failure to replace aged or damaged gaskets, allowing unmetered air to disrupt the engine's air-fuel ratio, resulting in erratic idle. Additionally, if the mass air flow sensor gets contaminated with cleaning agent residue, it provides inaccurate readings, leading to improper commands from the ECU. Whenever I address such faults, I first check if the throttle body is properly aligned and all screws are tightened, then use a diagnostic tool to verify the MAF sensor data, ensuring the sensor is clean. It's also important to note that the system needs a few days to adapt after cleaning. However, if the instability persists for more than a week, it's crucial to visit a workshop promptly to prevent engine damage. While this may seem like a minor issue, prolonged neglect can lead to increased fuel consumption and reduced vehicle lifespan.
After cleaning the throttle body, the idle becomes unstable. I believe the issue mostly lies in the electronic control system. The ECU has adapted to the opening degree of a dirty throttle, and after cleaning, the position changes, causing confusion as it fails to reset promptly. A common occurrence is disturbing the air flow sensor or oxygen sensor during cleaning, leading to inaccurate readings and an imbalanced air-fuel ratio. Additionally, an overly clean throttle body may expose flaws in the ECU's settings, requiring a learning period to adjust to new airflow parameters. With experience, I always recommend performing a basic reset using an OBD tool or letting the car idle for ten minutes after cleaning. If the instability persists, it's necessary to check the wiring and sensor voltages. Remember, frequent idle fluctuations are a signal—addressing them early can prevent increased engine vibration and damage to the powertrain.
