Why does the Chery QQ experience unstable idle after cleaning the throttle body?
2 Answers
It is because the throttle opening has not been reset. Causes: Due to long-term carbon buildup, the carbon deposits squeeze the throttle body, causing the throttle opening to expand accordingly. After cleaning the throttle body, if it is not reset, the throttle opening remains in the pre-cleaning state with carbon buildup, leading to increased air intake. In severe cases, this can result in unstable idle. Solution: Before cleaning the throttle body, disconnect the negative terminal of the battery. Alternatively, after cleaning, turn the key to the ON position and wait for a few minutes before turning it off. Then, turn it to the ON position again, press the accelerator pedal fully without starting the engine, and then start the car. The quickest method is to use a computer for matching.
I've experienced unstable idle after cleaning the throttle body several times, often due to insufficient attention during the cleaning process. For instance, if the cleaning agent isn't completely wiped off and residue remains on the throttle plate, it can cause sluggish opening/closing and unstable air intake. Additionally, unplugging electrical connectors may loosen sensor connections, causing them to send incorrect signals to the engine control unit (ECU). After cleaning, the ECU needs to relearn idle parameters—if no reset is performed, the computer can't adapt to the new conditions, resulting in erratic idle speeds. The solution is to disconnect the battery's negative terminal for a few minutes, then reconnect it and let the car idle in place for ten minutes to check for stability. If the issue persists, inspect whether the throttle body is installed correctly, whether the sealing ring is damaged, or simply switch to a high-quality cleaning agent to avoid corrosion. Cleaning is beneficial, but sloppy work can create more problems—it's recommended to have future maintenance handled by a professional shop.
