Why does the BMW fuel gauge not show full after refueling?
1 Answers
If the fuel gauge of a BMW 5 Series does not show full after refueling, it may be due to rust on the sliding resistor's contact, causing excessive resistance. How the car fuel gauge works: The fuel gauge is a relatively simple device. Current flows from the sender through a resistor, which may be wrapped around or located near a bimetallic strip. The bimetallic strip is connected to the fuel gauge needle via a linkage. Precautions when refueling a car: Avoid refueling during thunderstorms: This is a safety measure to prevent lightning strikes and potential fires. Since gasoline is highly flammable, refueling releases flammable vapor into the surrounding air, which could be dangerous if struck by lightning. Do not overfill the tank in summer: During hot weather, the optimal fuel level in the tank is between half and two-thirds full. A full tank increases engine load and fuel consumption (known as 'fuel-consuming fuel'). However, do not wait until the tank is completely empty before refueling. If the fuel gauge needle approaches or just reaches the red line, it's time to consider refueling.