Car fuel level sensor diesel and petrol

Fuel level sensor measures the tank charge level. The exact information about filling is transmitted to the fuel indicator. So the driver always knows how much fuel is there in the tank. In practice this function is very important, because without tank charge fuel measurement the driver would has to estimate exactly fuel consumption or regularly to measure tank charge fuel by him. In many makes of cars there are installed two fuel level sensors - one is on the driver’s side and another is situated on the place near the driver.

If the fuel indicator shows wrong information or constantly shows different numbers, this means that it is broken down. If the mistake appears when the tank is partially filled, in the majority of cases you need to search the mistake on the side near the driver, in other cases – on driver’s side. Before fuel level sensor’s substitution its content must be minimal. In this case the substitution won’t cost a lot. As a new sensor costs a lot, there is no need to substitute it. Sometimes you may install an old sensor with fewer costs.

In many cars it is necessary to have a special wrench to substitute the sensor. If the driver has it, then he can remove the sensor and install it back with little effort. If it is broken, don’t postpone the repair. Because of wrong data, for example, the car can stop as there won’t be fuel in the tank. If you need liquid cooling radiator, ignition runner, ABS system sensor, control block, cylindrical gear, ignition coil, central lock blocking or another part for your car, our online shop is that place where you will find a wide range of spare car parts.

How to detect malfunction of the fuel level sensor

First, inspect the component. In many cases, damage of the moving contacts is caused by oxidation under the action of water and dirt which takes place in course of time.

Resistance of the component should also be checked with the use of an ohmmeter. Note that the level of fuel in the tank will influence the results of measurement; therefore, the tank should be either empty or full to the top. If the tank is empty, resistance of the sensor should be between 230–330 Ohm. If the tank is full, the resistance should be 6 to 7 Ohm.

If the indicator does not react to changing the amount of fuel in the tank, dismantle the dashboard and check the wiring.

The component should be diagnosed together with the fuel system once a year, or after every 60 to 80 thousand kilometers in mileage.

You may notice that the fuel level sensor needs diagnostics by the following symptoms:

• the indicator shows that the fuel tank is empty;
• when driving, the indicator hand rises and falls abruptly;
• with the fuel tank full, the indicator shows incorrect fuel level.

The reasons of Fuel tank sender unit malfunctions

The most frequent fault of the component is worn slider and contact paths of the potentiometer. Due to the lack of contact, information about the fuel level is not transmitted to the dashboard. Drops of the car electrical system voltage, loss of wire integrity, influence of water on the contacts and their fouling prevent transmission of the electric signal, and result in incorrect operation of the indicator.

Sometimes, the reason of sensor malfunction is jamming the hand of the indicator due to accumulated dirt, or incorrect adjustment of the indicator hand. In this case, the malfunction is easy to remove by adjusting the indicator correctly. The component may also be jammed due to the indents that appeared on the surface of the float.

Using poor quality fuel and accumulation of dirt and water in the fuel tank cause accelerated corrosion of metal parts of the component. Sometimes, malfunction of the sensor is caused by a worn sealing gasket. If they constitute a single unit, the sensor is to be replaced.

Repair and replacement of the Fuel tank sender unit

If the contacts are oxidized, it is sufficient to clean them. When you disconnect the sensor, make sure not to damage the contact reeds. If damage occurs, the component is to be replaced.

If the indicator shows incorrect readings, you can adjust the hand of the indicator. To do so, shift the moving contact of the float into an extreme position and set the hand of the indicator to the corresponding position.

If the sensor has been damaged due to mechanical action, or its resistance changed, the component is to be replaced. After installation of a new component, it should be calibrated to increase accuracy of the displayed data.