Probably, many had to face the question of why the fuel level sensor does not work. And there is such a situation: after starting the engine, the sensor shows that the tank is empty, and while driving, the value on the sensor reaches the desired level. This option is also possible: the arrow is stuck at zero, but in fact another half a tank is filled, or the values \u200b\u200bon the dashboard are constantly changing. Without a sensor working as expected, it can be very difficult, especially on long trips. You need to constantly keep in mind the moment of the last refueling and its volume, and keep a can of fuel in the trunk just in case. Due to the mass of inconvenience due to one sensor, we will understand the problem in the article.
There are times when the sensor indicates that the tank is always empty or full. Moreover, the readings do not change, even if you change the fuel level.
Main reasons:
The sensor is defective and needs to be replaced.
Bad contact connection with the body.
Malfunction of the voltage regulator, which supplies incorrect power to the sensor.
The fuel gauge is faulty.
There are problems associated with the wiring of the sensor circuit, most often an open circuit.
Before drawing conclusions about a malfunction of the voltage regulator, it is necessary to measure the output voltage at the device's contacts. To do this, you will need to remove the dashboard and connect a voltmeter to the contact terminals. The sequence does not matter for checking devices. Most often, they begin to look for a problem in devices that are in the most accessible place.
There are many ways to check if it works. One of them is to check the resistance of the circuit. To do this, connect an ohmmeter to the disconnected contacts and pay attention to the readings. If they deviate from the norm, then you have found the cause of the malfunction. After that, the fuel level sensor is replaced.
Many tools can be used to check the fuel in the tank and evaluate the compliance of the sensor readings. Insert a clean dipstick into the tank and check if the tank is full. It is not necessary to have exact readings, in this case, approximate ones are fine.
Another way to check is to completely drain the gasoline from the tank and gradually top up. After each topping up, the resistance value of the sensor is monitored, which must necessarily change.
A similar option is used when removing the sensor from the tank. In this case, it is necessary to change the position of the float lever by hand. Thus, the check becomes much more accurate.
Non-electrical causes of sensor malfunction:
1. A hole appeared in the float, which caused it to be improperly immersed in gasoline.
2. Deformation of the fuel tank, as a result of which it interferes with the normal movement of the float.
3. Float lever defective. It can be its breaks and excesses.
If the sensor is OK, then the problem must be sought in the fuel gauge or electrical wiring. To check the wires, you need to measure their resistance or simply “ring”. The fuel gauge can also be checked in several ways. To diagnose its condition, you can pull the sensor out of the gas tank and turn it on. Move the float lever in different directions. If the readings of the device have not changed, then it really does not work.
Another way to check is to use a special calibration tester. It connects instead of the fuel level sensor and changes the resistance of the circuit. If the arrow of the device does not react, then the pointer must be replaced. If a magnetic sensor is used, then you can check the resistance of the circuit with an ohmmeter. As a rule, the resistance of such indicators is considered to be 10-15 ohms.
Types of fuel level indicators
Rheostatic fuel level sensor
The principle of operation of such a sensor is based on bimetallic strips, which move the indicator arrow on the instrument panel. The position of the strip depends on the resistance created in the sensor circuit. A float with a special lever is installed in the gas tank of the car. With an increase in fuel in the tank, the resistance decreases, which means that the current increases, which heats the strip, and it moves the indicator needle. When the fuel level decreases, the float lowers and the lever reduces the voltage in the circuit. Thus, the current decreases, and the bimetallic strip moves the indicator needle to another position, corresponding to the level of fuel in the tank.
Simply put, when the circuit is broken, the sensor stops working, and all the time it will indicate that the tank is empty, and if there is a short circuit in the rheostat circuit, it will indicate that the tank is completely filled with gasoline. There are a number of sensors in which the resistance changes quite the opposite. Accordingly, the indications will be different.
Fuel gauge with magnet
Such a sensor uses a magnet instead of a bimetallic strip, which is placed in a magnetic field. This field is created using three induction coils, which are energized. The principle of operation is that part of the voltage is applied to all three coils, and only the remaining part goes to the first turn. This part will change depending on the position of the magnet in the magnetic field, which changes the resistance of the circuit. The advantage of such a sensor is that its readings are more accurate and respond faster to changes in the fuel level.
This type of sensor differs significantly from its counterparts and is a modern device that shows a more accurate amount of fuel in a car tank. To indicate the fuel level, a digital display is used, which works based on the resistance data of the same circuit. A special voltage regulator receives information about the resistance and decides which part of the display needs to be turned on in order to display information about the state of the fuel level.
The fuel level sensor sometimes fails. In this case, the light marked on the panel lights up regardless of the amount of fuel present in the tank. It may stop working altogether. You can buy a new sensor, or you can repair the fuel level sensor. For this we need the following tools:
- a regular screwdriver, head "7";
Key "for 10";
Tester (multimeter);
New thermistor.
First, disconnect the negative wire from the battery. The rear seat must be removed to provide access to the fuel tank. The soundproofing cover over the hatch cover should be bent. Then you should unscrew 2 screws, temporarily remove the hatch cover. Now you have to disconnect the sensor connector. It is enough to loosen the hose clamps with a Phillips screwdriver. These hoses are responsible for supplying and draining fuel to the tubes. It is necessary to move the hoses from the tubes in turn, using the “10” key.
Remove the fuel receiver, which has a fuel level sensor, from the tank. The operation is carried out carefully to prevent damage to the float. Then we remove the gas receiver gasket. We close the cover of the petrol receiver during operation. We remove dirt from the sensor, inspect the device.
Using a tester or multimeter, we determine the health of the circuit. The main reason for such a breakdown of the sensor is a malfunction of the thermistor located in the flask. Then there will be no signal on the tester. The plate must be removed, because it covers the top of the flask. We remove the thermistor from the flask, from the lid too.
We mount a new thermistor in the flask. Sometimes even the resistance of the burnt resistor is unknown. Then we choose as follows. To the sensor connector, which is located on the gas receiver, we connect the trial resistance thermistor, turn on the ignition. Then the bulb should light up after five seconds.
It is necessary to pour gasoline into a small container, lower the connected thermistor. We expect five to seven minutes. If the selection is correct, the light will turn off. It is necessary to solder the "leg" of the thermistor into the middle of the bulb, it should not touch the walls. Then solder its upper “leg”. Assemble the sensor in reverse order. Connect the negative wire to the battery. After repairing the fuel level sensor, immediately check its performance.
Fuel consumption control is one of the most important tasks of the vehicle monitoring system. Teletracking offers to solve this problem - you can buy fuel level sensors of various models from us.
You can track all the operations that take place with the fuel in the GLONASS on-board unit using a special sensor. Such a fuel level sensor will show all refueling and draining performed during the selected period, as well as the level of fuel consumption. The information is displayed on the on-board terminal. All this is possible thanks to modern software that transfers the necessary materials to the server. If you have not installed a profile program yet, you can use, for example, Wialon Hosting.
Types of fuel level sensors
The fuel level sensor of the GLONASS onboard unit is a two-core cylindrical capacitor. It is divided into inner and outer hose. Due to the action of an electric current at the moment it is between the outer and inner hose, the capacitance of this capacitor is measured. Capacity is what eventually becomes the main indicator when transferring data to the on-board terminal. There is a persistent misconception that there is a special float inside the fuel level sensor. Remember! This is clearly a fake, which will fail rather quickly, because the float inside the fuel level sensor is an extra detail.
The GLONASS fuel sensor is divided into three main types:
- Analog. All indicators are displayed in Volts.
- Frequency. All readings are displayed in Hertz.
- Digital. All indicators have a numerical value.
It would be wrong to choose one and say that it is the best. Each system is unique and tailored to the individual needs of the client.
Fuel consumption control Purpose of the system
The fuel consumption control system has quite a few positive effects. Of course, first of all it is necessary to name economic. As statistics show, after installing GLONASS fuel consumption monitoring sensors, fuel costs are reduced by about a third. Note that the on-board terminal also plays a big role in this. The main advantage of the system is considered to be an instant ban on attempts to drain fuel. The organization controls all processes and catches even the most cunning methods of theft. With this system, it is almost impossible to carry out fraud with fuel. At any time, you can evaluate a specific fuel consumption or view the amount of fuel that has been filled. Of course, we want to think that honest people work in the company, but as practice shows, the real costs are significantly lower than the figures provided in the reports.
Installing a fuel sensor is a guaranteed elimination of “leftists” and fuel theft. This means an increase in the efficiency of each car and the company as a whole. This is really beneficial for you and your business.
Fact: Installing a fuel level sensor connected to the onboard terminal of the GLONASS system pays off within six months.
Fuel Level Accuracy
Each fuel level sensor undergoes various tests during the production process. In the technical data sheet, the manufacturer is obliged to indicate the maximum error for the correct use of the equipment - 1-3% of the total indicator of the fuel tank. This is a normal margin of error. Measurement accuracy can be significantly affected by:
- temperature regime
- battery level
- fuel quality
- software settings.
The programs that exist today allow you to use the data filtering mode, which corrects distorted information, filtering out unnecessary information. The owner of such a system is obliged to build all the settings on an individual basis.
Installation of fuel level sensors
You can install a fuel monitoring system both independently and with the help of a professional company. Of course, the second option is more reliable and practical. As a rule, it is not recommended to install the meter yourself, since for its installation it will be necessary to drill a hole in the tank, and then calibrate it. It is safer to entrust such work to professionals. Moreover, by contacting Teletracking specialists, you will receive inexpensive services for the installation and configuration of all the necessary equipment.
After installation, control tests will be carried out, which will show the correct operation of the system, as well as allow you to deduce the error. After that, the received data is transferred to the system administrator, who will work with the software.
Each meter has a long-term warranty, and installation is carried out in accordance with all requirements, which guarantees high quality, reliability and efficiency of the entire system.
By the way, on the operation of all systems presented on the site, you can get advice from our specialists by calling or using the special "Feedback" form.
Fuel consumption monitoring system price
|
FLS Arnavi LS-2DF Price 6500.00 |
The choice of specific equipment should be approached carefully, based on the individual characteristics of your organization and the existing fleet of vehicles. You should buy a new fuel level sensor, the price of which is prohibitive, if you really have most of the work related to fuel, and the costs associated with refueling and refueling are very high. In this case, the costs are justified. And it’s a completely different matter if you need to follow a small fleet, and there are no big claims to fuel consumption - then you can buy a cheaper fuel level sensor. There is no reason to buy heavy-duty equipment here, conventional control systems will do. The Teletracking company is always ready to help you professionally select the necessary equipment. We will advise you in any matter.
By contacting Teletracking, you can not only buy a fuel level sensor and other monitoring equipment at a great price, but also install and service it. We also offer equipment for GPS/GLONASS monitoring, its configuration and installation.
The sensor, or fuel level indicator, is designed to measure the filling of the vehicle (TC) tank with gasoline or diesel fuel. Such devices are usually used in conjunction with equipment that supports the communication and processing of analog and digital signals. First of all, it is equipment compatible with fuel level sensors that has various control units, as well as concentrators and GPS monitoring devices. For example, such devices that work together with sensors include AutoGRAPH-GSM, which not only registers the fuel level in the tank, but also processes a large array of other data, including those coming from the GPS / GLONASS module. When exchanging data, various interfaces are used, including those with digital-to-analog converters.
Are the sensors different for petrol and diesel? There is no difference between them. This means that the measurements use the same sensors. But their data in one and the other case may differ. This is due to the different dielectric constant (Eps) of gasoline, which is approximately 2.3, and diesel fuel with Eps of about two units. The higher the specified value, the greater the measurement error. This indicates that when the level of diesel fuel changes, the sensor readings will be more accurate.
Depending on the type of output signal, sensors are:
- analog;
- frequency;
- digital.
Sensors with analog output signal
Such a fuel level sensor in the tank belongs to standard float models and has been used most often until recently.
The principle of operation of such a device is quite simple. The value of the fuel level is determined by current or voltage values, which are then interpreted into understandable data, expressed in liters or parts, calculated from the full volume of the fuel tank. Information is transmitted using an analog output signal.
For example, if a signal is set at the sensor output in the range from 0 to 10 V, then we can say that a signal of 5 V will correspond to a half-filled tank. But the whole question is in the accuracy of measurements. Sensors of this type have low noise immunity, which often leads to severe distortion of the results.
Sensors with frequency output
The frequency signal at the output is something intermediate between digital and analog. This is frequency modulation with an encoded output value. The error of the measured values using such a sensor is already less than that of an analog one.
Sensors with digital output signal
The implementation of digital output for sensors became possible after the development of microprocessor technology. The microprocessor is able to carry out instant recalculations of large data arrays and align and correct the initial measurements.
The digital fuel level sensor is a microprocessor with a corresponding output signal. Such a device has good noise immunity and provides high measurement accuracy. The data is transmitted in digital form and the only source of error is the meter itself, or rather, its contamination, which increases with operation.
All digital sensors are electronic.
Fuel level sensors, the capacitive parameters of which depend on coaxial capacitors filled with a liquid dielectric, are called capacitive and also belong to the digital type. They are installed directly in the fuel tank and provide continuous reading and analysis of the level of gasoline or diesel fuel in the tank.
The electronic fuel level sensor, which, as mentioned above, is digital, can also be ultrasonic. At the ultrasonic sensor, the signal supplied by the emitter is processed by the electronic unit, converted to digital and transmitted to the output of the device.
All considered types of fuel level sensors have their positive and negative qualities, and when choosing, you should always proceed from the technical characteristics of a particular model.
The fuel level sensor is a device that is necessary to determine the degree of filling of the fuel tank (on the car - the fuel tank). As well as indirect control of the consumption of gasoline, diesel or other fuel, which are one of the main operational parameters of the car. The visualized representation of the sensor readings is displayed using the corresponding pointer, both of these elements are interconnected.
Operating principle
The sensor transmits a signal, which corresponds to a certain level of fuel in the tank, to the pointer. Depending on the type of signal, analog and digital sensors are distinguished. The first type of sensors is not widely used today due to the high degree of their unreliability. The digital fuel level sensor converts analog data to digital format and then provides an output value that takes into account the correction for the uneven distribution of fuel in the tank, as well as the geometric features of the tank. Compared to analog, this device has a much lower measurement error.
Float measuring devices
In modern cars, the level of gasoline or diesel fuel is measured using digital potentiometric (float) devices. In such systems, the position of the float, made of foam, light metal or plastic, sets the value of the fuel level in the fuel tank.
This scheme has a number of advantages:
- simplicity of the device;
- reliability in operation;
- low cost.
The disadvantages include the mobility of the contacts, which can lead to their oxidation and wear.
By design, there are two types of float sensors:
- lever;
- tubular.
Device Features
In the lever version, the float is connected to a rheostat through a metal lever. When the fuel level in the tank changes, the float moves. This leads to the rotation of the lever associated with the moving contact of the rheostat. The resistance of the latter changes, which entails a change in the value displayed on the fuel gauge. The lever design is universal and can be used in fuel tanks of any geometric shape. 
Tubular fuel level sensor works as follows. The float moves along a guide located inside the tube. Parallel to the direction of movement of the float, wires with contact rings are laid, by closing of which the float fixes the corresponding value of the fuel level.
The main advantage of such a scheme is the stability of its readings during ascents, descents and turns of the car, when fuel level fluctuations occur.
However, its use is limited by the geometric shape of the fuel tank. 
Alternative fuels
As already noted, lever and tubular systems can be used for gasoline or diesel, but, for example, they are completely unsuitable for ethanol, methanol, biodiesel. The contact of these types of fuel with the elements of the sensor leads to the rapid failure of the latter. In such cases, non-contact fuel level sensors are used, for example, inactive magnetic position sensors, in which the structural elements are hermetically isolated from external aggressive influences. They also use a float connected to a magnet. The magnet moves along a sector on which metal plates of various lengths are located. Depending on the value of the transmitted signal, the value of the fuel level in the tank is determined.
The most common faults
Obviously, it is possible to determine the malfunction of the fuel level sensor only indirectly - through malfunctions in the operation of the fuel level indicator. The most common faults are:
Withdrawal
In many of the cases described above, in order to check or repair the fuel level sensor, it must be removed and then reinstalled. The removal procedure is carried out in the following order.
- For a gasoline car, it is imperative to remove the negative terminal of the battery.
- Provide access to the sensor, depending on where it is installed - unload the contents and remove the trunk upholstery or remove the rear seat cushion.
- If a protective plate is installed on top of the sensor, unscrew the mounting bolts and remove it.
- Clean the fuel level sensor and the surface of the tank near it from dust and dirt.
- Disconnect suitable electrical wires (it is recommended to pre-mark them).
- Unscrew the bolts securing the fuel sensor to the tank and carefully remove it to avoid damage to the structural elements. In some cases, before removing it will be necessary to unscrew the plastic cover.
Installation
Before reinstalling the fuel level sensor, the following operations must be performed.
- Clean the seat of the old sealant.
- If there is a new gasket, install it in its seat, aligning the holes for the mounting bolts. For cars of solid age (10 years or more) with a new gasket, it is recommended to use a sealant.
- Assembly is carried out in the reverse order of removal.
- After reassembly, check the readings on the fuel gauge.
- Drive 30-50 km, access the fuel gauge again and check for fuel smell and leaks.
Fuel and battery voltage indicator for car V.4 on the microcontroller (MC) ATMega8 Nokia 1202 display with RC5 IR remote control.
But, so that everything is in order and in one place, first I will briefly mention the previous versions, maybe someone will find something useful.
V.1 in the standard case of the indicator on the Nokia 3310 display
The attached archive contains all the materials preserved for this version, including the source code in C in CodeVisionAVR.
V.2 in the standard case of the indicator on the Nokia 1110 display
V.3 universal without case also on display Nokia 1110 and compatible 1110/1200/1110i/1112
Here I post all the materials, including the source code in C in .
V.4 universal without case on Nokia 1202 display, RC5 format IR remote control
Scheme
Processor scheme:
Possible replacements:
U4 LM2576 - LM2575
D6 SS16 - any Schottky diode with similar parameters
U2 TSOP 32136 - you can put any IR receiver at 36 kHz with a power supply of 5V
D1-D3, D7 SMBJ6.0CA - can be replaced with conventional 5.1V zener diodes
Boards
When mounting the display, the cable is first soldered, then the display is wrapped on the other side of the board and put on double-sided tape, for reliability, you can also hook it on one corner with a thin wire.
Compatible RC5 format remotes
Surely these are not all possible types of RC5 format remotes, but these are the ones that I managed to find and check.
Connection
The connection is made according to the diagram below.
Signal dimensions
taken at any point from the instrument panel backlight, this signal is used to switch the brightness of the display backlight day and night.
Nutrition
, allowable supply voltage limits 8-30 V.
Sensor
connected directly to the input, the standard indicator must be turned off.
The boards are connected to each other according to the given signals; on the processor board, signals for in-circuit programming are output to the same connector.
If anyone hasn't noticed yet, pay attention to the IR receiver, on the board it is displayed with the working part towards the board-to-board connector, and on the real board it has the working part towards the terminal block, this is not a mistake, these are varieties of IR receivers, for example TSOP2136
It is installed as indicated on the circuit board, and TSOP31236
It is installed as it is on my board in the photo, but in general you can install any IR receiver at 36 kHz with a 5v power supply.
Control
Controlled by digital buttons 1, 2, 3, 4, 5, 6, 8
1
- entry to settings
2, 8
- move up/down the settings
4, 5
- change the selected parameter -/+
3
- Exit settings mode
Capacity
- tank capacity 10-99 liters is selected (for proper operation, the entire selected range must be calibrated)
Inertia
- value 2-10 is selected (principle of operation: once per second the sensor data is written to the buffer with a shift, the inertia value indicates how many values are taken from the buffer to calculate the average displayed value)
light day
/
light the night
- respectively setting the brightness level of the display backlight day / night 0-254
Contrast
- toggles between two extreme values minimum/maximum contrast
Inversion
- switching display mode normal / inverse
2
- enter tank calibration mode
2, 8
- change in liters +/-
5
- saving the current value of the sensor in the selected cell liters
3
- exit tank calibration mode
Liters
- the value of the liter is selected in which the current value of the sensor will be saved
In mind
- the stored value of the sensor in the selected liter is displayed
Sensor
- displays current sensor readings
Setting
Adjustment of the input divider to the resistance of the sensor in the tank:
Resistor R5 and the sensor in the tank form an input voltage divider
Where:
Vs - supply voltage equal to 5v.
Rd - maximum resistance of the sensor in the tank
Vo - voltage supplied to the ADC MK, it is calculated by the formula Vo = Vs * Rd / (R5 + Rd)
A R5 of 1k will work for most sensors, but if you want to make fuller use of the ADC range, you need to choose R5 so that the Vo is close to 2.5v.
For example: if the maximum resistance of the sensor is Rd=400 Ohm, with R5=1 kOhm Vo will be equal to 5*400/(1000+400)=1.4... V., it would be more correct to put R5=430 Ohm with such a sensor, then Vo will be 2.4...in.
Reference voltage setting:
By selecting resistors R14, R15 we achieve a voltage of 2.56v at pin 3 of TL431
Indication voltage setting:
1. Connect the indicator to the on-board network
2. We connect a voltmeter in parallel
3. With resistor R2 we set the voltage on the indicator as on a voltmeter
Tank calibration:
1. We enter the settings "1" set the required tank capacity, exit the settings "3"
2. Enter tank calibration mode "2"
3. When the tank is empty, set liters "2", "8" to 0000, press "5" - save
4. Pour 1 liter of gasoline into the tank, set liters to 0001, press "5" - save
5. Pour 1 liter of gasoline into the tank, set liters to 0002, press "5" - save
etc. until the tank is full, then press "3" - exit the calibration mode, that's it, the indicator can be used.
The archive contains circuits, circuit boards, boards in DipTrace format, firmware.
A short video of the device in action:
I myself have been using the second version for the third year and it has never let me down, but nevertheless
Remember this is still not a professional device, so I warn you as a standard: If you assemble this device, you assemble it at your own peril and risk, the author does not bear any responsibility for the consequences of using this device!
Attention!
The correct value of the resistor R11 in the version 4 circuit is indicated in the list of elements and is 1.8 kOhm.
Versions 1 and 2 are posted as is, i.e. all information on them, schemes, firmware, source codes is what is left of these versions at the time of publication of the article, and I do not guarantee that these are the latest, correct and fully working versions of firmware and source codes. These versions are posted purely for information and for those who like to "dig deeper" into the source codes themselves. For those who do not understand MK programming, I strongly do not recommend making these versions, since there will be no technical support for them.
List of radio elements
| Designation | Type | Denomination | Quantity | Note | Shop | My notepad | |
|---|---|---|---|---|---|---|---|
| Processor scheme: | |||||||
| U1 | MK AVR 8-bit | ATmega8 | 1 | To notepad | |||
| U2 | IR receiver | TSOP 32136 | 1 | Any at 36kHz with 5V supply | To notepad | ||
| U3 | Reference IC | TL431 | 1 | To notepad | |||
| U4 | DC/DC switching converter | LM2576 | 1 | LM2575 | To notepad | ||
| D1-D3, D7 | Diode | SMBJ6.0CA | 4 | Or a 5.1V zener diode | To notepad | ||
| D4 | rectifier diode | SM4007PL | 1 | To notepad | |||
| D6 | Schottky diode | SS16 | 1 | Any Schottky diode with close parameters | To notepad | ||
| C1, C2, C8 | Capacitor | 0.01uF | 3 | To notepad | |||
| C3, C5, C7, C12 | Capacitor | 0.1uF | 4 | To notepad | |||
| C4 | 4.7uF 10V | 1 | To notepad | ||||
| C6 | Capacitor | 1 uF | 1 | To notepad | |||
| C9 | electrolytic capacitor | 100uF 25V | 1 | To notepad | |||
| C10 | electrolytic capacitor | 330uF 10V | 1 | To notepad | |||
| C11 | electrolytic capacitor | 10uF 16V | 1 | To notepad | |||
| R1 | Resistor | 75 kOhm | 1 | To notepad | |||
| R2 | Variable resistor | 10 kOhm | 1 | To notepad | |||
| R3, R4, R6, R10, R13 | Resistor | 100 ohm | 5 | To notepad | |||
| R5 | Resistor | 1 kOhm | 1 | To notepad | |||
| R7, R8, R12 | Resistor | 10 kOhm | 3 | To notepad | |||
| R9 | Resistor | 4.7 kOhm | 1 | To notepad | |||
| R11 | Resistor | 1.8 kOhm | 1 | To notepad | |||
| R14, R15 | Resistor | 3.9 kOhm | 2 | To notepad | |||
| L1 | Inductor | 100 mH | 1 | To notepad | |||
| L2 | Inductor | 330 mH | 1 | To notepad | |||
| F1 | Fuse | 1 | |||||
