What Causes a Sudden Increase in Fuel Consumption?
2 Answers
The reasons for a sudden increase in fuel consumption are: 1. After cleaning the throttle body, it was not matched with the engine control unit or the matching was unsuccessful; 2. There is a fault in the engine's electronic control system, causing the air-fuel mixture to be too rich; 3. Damage to the engine's ignition coils or spark plugs, or fuel injector leakage; 4. A malfunction in the engine cooling system, resulting in the engine temperature being too low and remaining in warm-up mode; 5. Excessive carbon buildup in the engine, leading to incomplete combustion; 6. A fault in the fuel tank ventilation system, causing fuel vapor leakage. The method to calculate fuel consumption is to fill up the tank after using up a full tank of fuel, reset the trip meter on the dashboard, and drive normally. Once this tank of fuel is used up, calculate the total distance traveled in kilometers, then divide the number of liters of fuel added by the distance traveled and multiply by one hundred to get the fuel consumption per 100 kilometers.
After driving for over ten years, I've found that a sudden increase in fuel consumption could be due to several reasons. The most common is excessive carbon buildup in the throttle body, which restricts engine airflow—just like how a person can't run well when short of breath. Worn-out spark plugs can also cause incomplete fuel combustion, especially in vehicles that have run over 60,000 kilometers. Low tire pressure increases rolling resistance, akin to running while dragging a sandbag. A faulty oxygen sensor can mislead the engine control unit into injecting excessive fuel. Additionally, a clogged air filter starves the engine of oxygen, leading to incomplete combustion. All these issues can cause the fuel gauge to drop rapidly, with a suddenly higher fuel bill serving as a clear warning sign.