What is the reason why the fuel gauge does not show full after refueling?
2 Answers
After refueling, the fuel gauge may not show full because the engine was turned off, and the ignition switch was not in the final position P before refueling. When the engine is started again, the fuel gauge remains at its original position. If this is the case, the situation will gradually recover. If not, it could be due to poor contact between the main fuel level sensor and the auxiliary fuel level sensor. Additional information: The fuel tank is divided into two parts: 1. Main fuel tank; 2. Auxiliary fuel tank: Each part has its own fuel level gauge, and the two gauges are connected in series. The fuel gauge displays the average of the total remaining fuel in both parts.
Last time I also encountered this situation where the fuel gauge was still one bar short after filling up to the pump's automatic shut-off. Later, I found out it was due to a stuck fuel level sensor inside the tank. This component works like a float ball in the fuel tank and over time, it can get stuck by sludge or displaced by fuel flow, causing inaccurate readings. Sometimes, driving over bumps can reset it on its own. However, if this persists, especially in older vehicles, it might indicate sensor wear leading to incorrect resistance values, which sends wrong signals to the dashboard. Additionally, if you drive on mountainous roads or make sharp turns right after refueling, the sloshing fuel can cause the gauge needle to fluctuate, but it usually stabilizes after driving on flat roads for a few minutes. If still concerned, it's best to have a mechanic inspect and possibly replace the sensor.
