Call it a "gas gauge" or a "fuel gauge", this device represents the level of fuel which is present in the fuel tank of any vehicle. It is designed in two parts, viz., an indicator and a sensing unit. What I am going to say here should be a common observation for any uninitiated person. In a car, you must have noticed a unit on the dashboard that indicates the moderation of fuel. There is letter 'E' and letter 'F' spaced with markings, which means the fuel is either "empty" or "full". That indication is usually presented by a fuel gauge needle which floats in the unit. This needle is connected to a potentiometer in the sensing unit.
When a vehicle runs out of fuel and faces an empty fuel tank, the needle float drops to the empty indicator, showing the driver that the vehicle is very low on fuel. Some cars show a 'low fuel' yellow light to indicate that there is no fuel in the car. If you infer to the working of a fuel gauge, the process is pretty simple, and fail-safe too. However, sometimes, an issue can arise regarding this fuel gauge and it can stop working or work in an erratic manner.
Working of a Fuel Gauge System
As we have already discussed, a fuel gauge unit has two parts, viz., sensing unit and an indicator. The sensing unit has a floating needle and the indicating unit measures the current. Since the sensing unit has a needle float linked to a potentiometer, the moment a car faces an empty fuel tank, the float slides and falls to the empty indicator, i.e., 'E'. The floating needle moves along the resistor and increases its resistance value. If you happen to notice a low fuel light in the unit, this means the resistance is at a point lower than the usual. The indicator unit is mounted on a dashboard, and its basic function is to display and compute the total amount of electricity passing through the sending unit.
So, after inferring to the working of both these systems, what we learn is that when the fuel tank in the car is completely filled, there is maximum electric current in the unit and the needle points to the letter 'F' (indicating full tank). On the other hand, when the fuel tank is empty, the electric current is minimum, making the needle point to the letter 'E' (indicating empty tank).
This was the general working of a fuel gauge unit in a car. Some people aren't usually aware of the fact that there is a sensor situated inside a car that monitors the fuel level. It is a mechanical device which stores the vehicle's fuel in the gas tank. It is this little piece of information most people are generally oblivious to. Hence, the working of fuel gauge was needed to be explained to comprehend the relative problems, in case you are facing one.
Possible Problems and Solutions With Fuel Gauge
- Add a fuel injector cleaner to the fuel tank. There will be an indication of full tank. Drive the car for about a few miles and if the indicator still shows full, there is a problem with the fuel level assembly. Get it replaced or repaired.
- When the car starts, the fuel gauge float can fluctuate and jump from full mark to an empty mark, regardless of the amount of fuel present in the tank. The needle or float is faulty or botched up in this case. Tap the unit with your hand or call in for a check.
- When the vehicle is put into a reverse gear and when the driver operates the gear selector, the fuel gauge needle deflects randomly, at times pointing to E or at times to F.
- One more problem could be when the vehicle shows the right or left signal indicator and blinks, on every blink the needle moves up and down on the line of the unit. Also, when the directional light switches on or off, there will be a slight sound or change in pitch from the fuel pump. This is a common problem that any vehicle faces. All of this indicates you need to go to a mechanic and get your fuel gauge checked or replaced soon.
- The most obvious problem is due to the faulty fuses and connector wirings. There is usually a black or yellow wire securing the connector of the fuel tank. If it is not grounded well or has lost connection, that will cause the fuel gauge unit to show inaccurate readings. Take the help of a mechanic to rewire them well.
Every mechanical system is bound to face failures, so just keep a cool head and sort all your car problems peacefully.