Why does fuel consumption increase after cleaning the throttle body?

[Malcolm]

The reasons for increased fuel consumption after cleaning the throttle body: 1. The throttle body was not properly matched with the engine control unit (ECU) after cleaning, or the matching was unsuccessful; 2. For some vehicle models with less capable ECU self-learning functions, even if the throttle body and ECU are correctly matched, there may be a temporary increase in fuel consumption for a short period, which will return to normal after driving for some time. The throttle body is a crucial component in electronic fuel injection systems. Its upper part connects to the air filter (air box), while the lower part connects to the engine block, making it known as the "engine's throat." When the driver presses the accelerator pedal, the signal is transmitted to the ECU, which then controls the throttle opening to ensure sufficient air intake for the engine. When symptoms like engine shaking or poor acceleration occur, they are often related to throttle body contamination. Cleaning the throttle body can not only reduce fuel consumption but also make the engine more responsive and powerful.

[MacAshlyn]

After I cleaned the throttle body myself last time, the fuel consumption suddenly skyrocketed, which was really puzzling. Later, I asked a car repair friend, and he said this might be because the throttle position sensor was accidentally touched during cleaning, causing signal errors that made the ECU think there was insufficient air intake and compensate by injecting more fuel. Or, after cleaning, the carbon deposits were gone, but the computer still remembered the old data and hadn't reset, requiring more driving to adapt. After cleaning, it's best to disconnect the battery negative terminal for 10 minutes, then reconnect it and let the car idle for a few minutes to allow the system to relearn the new position. Using a diagnostic tool to reset is even more convenient. When cleaning, choose a specialized cleaner and avoid strong corrosive ones to prevent damage to electronic components. I think DIY is fun, but you have to be careful, otherwise it can cause trouble. High fuel consumption makes driving unpleasant, so it's useful to learn more about maintenance knowledge.

[HoldenLynn]

Increased fuel consumption after throttle body cleaning is technically caused by either a damaged throttle position sensor or an unreset ECU. I've seen this many times - if cleaning solvent seeps into the sensor during cleaning, it can damage internal circuits, causing inaccurate signals that make the ECU inject extra fuel to maintain operation. Alternatively, after carbon deposits are removed, the throttle opening changes but the computer's memory lags behind, requiring it to learn the new state. The solution is simple: after parking, restart the engine and let it idle for 15 minutes for self-adaptation, or disconnect the battery to reset. If the sensor is damaged, it needs replacement - inexpensive but should be done promptly. Avoid scrubbing with toothbrushes during cleaning to prevent metal part wear and air leaks, which can cause additional air intake. Professional cleaning every 20,000 km is recommended to prevent carbon buildup that could lead to major repairs.

[DeHeidi]

I've been driving for many years, and it's common to experience increased fuel consumption after cleaning the throttle body. The main reasons are often due to careless operation during cleaning, such as loose sensors or poor electrical connections, which can cause the ECU to misjudge the air intake and supply more fuel to compensate. Another reason could be that the ECU hasn't updated its data promptly after the carbon deposits are removed. Solution: Let the car idle in place for a few minutes to learn the new position. If that doesn't work, take it to a repair shop to reset the computer—don't attempt it yourself to avoid damaging components. After cleaning, monitor fuel consumption changes; it usually takes a day or two to adapt. Keeping the throttle body clean benefits the engine, but always opt for professional service to ensure safety—safe driving comes first.