The instrument panel or instrumentation may be missing information on certain manufacturers’ vehicles on specific models.
In today’s world, it is not difficult to locate automobiles that do not offer an engine temperature reading other than a blue or red LED to indicate whether the engine is cold or hot. In a similar vein, we can also discover vehicles that do not have a rev counter. What has never been missing, and will never be missing, is a fuel gauge.
This can be a clock with a moving needle inside or a digital graphic. Its purpose is simple, but it is critical.
The gauge shows how much fuel is left in the tank, and informs us if we are in a ditch with the vehicle stopped and out of fuel by flashing the warning lights or turning on the traditional reserve light.
The fuel gauge, like any other vehicle component, is susceptible to malfunction.
Causes of a Fuel Gauge Not Working Correctly
This section covers the common causes of a fuel gauge not functioning properly. These are:
- Faulty sending unit
- Faulty gauge
- Low fuel pressure
- Bad connections.
1. Faulty sending unit
The sending unit is the device in the tank that measures the amount of fuel in the tank. It has a float that rises and falls according to the fuel level. If this float is stuck or disconnected from the mechanism, the reading will be incorrect.
2. Faulty gauge
The fuel gauge is a device located on the dashboard that indicates the amount of fuel remaining in the tank. If this part malfunctions or shuts off completely, you will not know when there is no more fuel left in the tank.
3. Low fuel pressure
Low fuel pressure can also be the result of a faulty fuel pressure regulator. Replacing the fuel filter and making sure the engine is kept in good working order can help prevent low fuel pressure.
4. Bad Connections
If you think your fuel pressure gauge is faulty, the problem may be in the connection between the fuel tank and the gauge. The line may be clogged with dirt or rust, making it difficult to get an accurate reading.
How Do I Know if My Fuel Gauge is Accurate?
The easiest way to know if your fuel gauge is accurate is to know how many miles you can drive per gallon.
If you know the car gets 20 miles per gallon, then the fuel gauge should read at least 20 when you are in town and at least 30-40 when you are on the highway.
There are a few other ways that people have invented, but none of them are reliable and may not work for all cars.
How To Fix Fuel Gauge
This task can be complicated. The first point is to detect the origin of the fault, which, as we have seen, can have very different origins. Once the problem has been located, the problematic part must be replaced.
Checking the fuel gauge
We will be able to begin to try to discard a mechanical or electrical breakdown of the panel. For it, we will bridge the two contacts of the pressure gauge (or putting the positive to the ground) and we will verify if the gasoline level rises up to the top. If it marks the maximum, the problem is not of the control panel or its wiring. In some vehicles with voltage limiters, this checking system may not work.
Check the potentiometer
If this part is correct we proceed to check the fuel gauge potentiometer (fuel level sensor). To do this we must follow the following steps:
- Set the multimeter to measure the proper resistance range, which is indicated by the Greek letter Ω. In this particular case, we must turn the wheel to the in 2-kilo ohms.
- Loosen the leads leading to the meter.
- Place the test leads of the multimeter in the places where the wires were placed.
- While the test leads are in place, move the meter up and down by hand.
- If operating correctly, a steady, linear change in the resistance measured by the multimeter should be observed. For example, a progressive change with no drop from 33 ohms to 213 ohms.
If you find that the fuel gauge is malfunctioning, you can purchase a new one for prices typically ranging from $30 to $60. Although if your model is premium, the price can go up to 100 euros or even more.
Another test that must be done to the fuel gauge is the voltage that reaches it, which must be 12V.
Fuel Gauge Sender Replacement Costs & Repairs
The price will vary depending on the defective item. If it is a cut wire, a bad ground, or a fuse, the repair may cost a few dollars if we take it to the mechanic, or nothing if we do it ourselves.
If the source is the pressure gauge, we will have to see if cleaning will solve the problem or if, on the contrary, we will have to replace the whole assembly or even the tank pump (about $200).
The problem may also be in the tank itself, which would be a more expensive repair if it had to be replaced.
If the fuel clock is the source of the problems, you would have to see if that part number is sold separately or if the entire clock panel needs to be replaced, which can be very expensive.