EntranceWhat is a mass air flow sensor (MAF) and what does it come with? The main symptoms of a faulty mass air flow sensor and how to check it.
Sensor mass flow air flow sensor (MAF), is attached to the air filter and determines the amount of air passed through it. From correct definition this indicator depends on the quality combustible mixture. Malfunctions will immediately affect the operation of the engine.
Signs of damage
At the first sign of engine malfunction, do not panic, rush to the store and buy a new mass air flow sensor. There may be an assumption that the mass air flow sensor is damaged. How to check its operation? First, you need to listen carefully to the car. It will indicate that the mass air flow sensor is faulty and will behave as follows:
The computer will display a “Check Engine” error;
Power will decrease;
Fuel consumption will increase;
The engine will not start well;
The dynamics will decrease.
What to do if the mass air flow sensor does not work correctly? How can I check its condition?
Option 1: Disable
With the engine off, disconnect the connector from the mass flow sensor. The device will turn off, the controller will go into emergency mode, and the fuel mixture will be prepared taking into account the current throttle position. The engine will again report the transition to this mode; it should maintain a speed of more than 1500 rpm. Final conclusions about the malfunction of the mass air flow sensor can be drawn if, while driving, you realize that after disconnecting the sensor, the dynamics have improved. Note: ECU modifications Y-7.2 and M-7.9.7 will not increase engine speed after disconnecting the mass air flow sensor.
Option 2. Firmware
It is possible that the ECU has already been modified by flashing firmware, then it is not entirely clear how it will behave when using the option given above. In this case, the mass air flow sensor may also not work correctly. How to check this? Take a plate 1 mm thick and insert it under the damper stop. After we got up, disconnect the terminal from the mass air flow sensor. If the engine continues to run, then the cause of the malfunction is in the ECU, namely in the IAC steps. They do not respond to emergency mode without a mass air flow sensor.
Option 3. Diagnostics with a multimeter
This option is acceptable for diagnosing Bosch sensors with indices: 0 280 218 004, 0 280 218 116, and also 0 280 218 037. On the tester, we set the measurement limits to 2V, in constant voltage mode. (orientation from the salon):
Signal input - yellow;
Sensor power supply - gray-white;
Grounding (minus) - green;
To the main relay - pink and black.
Note:
Wire colors are indicated for most models, colors may vary, but the meaning of the pins is the same.
Measurement procedure
After turning on the ignition, without starting the engine, we perform a scan. We connect the red probe of the device to yellow wire Mass air flow sensor, and black to green. So we measure the voltage and record it. Comparing the received readings with the manufacturer’s recommendations, which will allow you to judge the performance of the device. The new mass air flow sensor has a voltage of 0.996-1.01 V.
Device performance parameters depending on voltage:
1.01-1.03 - the sensor is operational;
1.03-1.04 - operational, but the sensor resource is almost exhausted;
1.04-1.05 - the resource is exhausted, if there are no signs of malfunction, you can use it, but it’s time to purchase a new one;
1.05 and more - defective, requires replacement.
Note:
To check the mass air flow sensor, you can find out about the “voltage from sensors” parameters.
Option 4. Visual inspection
Use a screwdriver to unscrew the clamps, remove the corrugation, and inspect the sensor and corrugation. All surfaces must be dry, free of oil deposits and condensation. Reasons for contamination of the air flow sensor:
Contaminated air filter;
The oil level is higher than normal;
The ventilation system is clogged.
Having eliminated the causes of contamination of the mass air flow sensor, it is necessary to correct the consequences, and this will require cleaning the mass air flow sensor. Using a 10mm wrench, unscrew the sensor mounting bolts and separate it from the air filter. There should be a rubber ring on the sensor to prevent the leakage of untreated air. If missing or misplaced, the input grid of the device in question will be covered in dust. This may cause the sensor to malfunction.
Installation sequence:
A sealing rubber band is put on the device;
The sealing skirt is checked;
The sensor is installed in the filter housing.
Replacement procedure
Turning off the ignition, remove the plug from the sensor. Loosen the clamps and disconnect the air inlet pipe. Next, unscrew the sensor and remove it from the filter housing. To unscrew it, you will need a 10mm wrench. After the inspection, the question will again arise: if the mass air flow sensor is faulty, how to check its functionality. Having assessed the condition of the device during diagnostics, you should not immediately purchase a new one. It should be said that the cost of a mass air flow sensor ranges from 1,500 to 2,000 rubles. But you can simply eliminate the contamination and spend a maximum of 200 rubles.
Detergents
In order to properly wash the mass air flow sensor, it must be removed; the removal procedure has already been described earlier. There is a mesh inside the device. There are 2-3 sensors installed on it, in the form of small wires. During operation, parts become dirty, which leads to malfunction. To give the device a second life, you need to clean the mesh and sensors; a carburetor cleaner is suitable for this. By spraying the product, we wash away contaminants from the inside of the air flow sensor. Complete removal of contaminants may not occur the first time; the procedure will have to be repeated. All subsequent spraying should be carried out after the product has dried. When cleaning the sensor, it is worth inspecting the condition of the pipes - if there are contaminants, remove them. The use of a product to remove contaminants from a carburetor shows that 8 out of 10 devices begin to function properly after treatment. correct mode. But in some cases you have to buy a new mass air flow sensor.
Conclusion
Now check the mass air flow sensor on our own can be considered completed. And questions about whether the mass air flow sensor is working and how to check its condition can be answered with a 100% guarantee at a service station by conducting a diagnostic examination using special equipment.
The most obvious and early sign of a faulty or failing mass air flow sensor is flickering lighting. dashboard. However, many malfunctions can cause this effect. Therefore, it is necessary to test the car’s on-board computer to make sure that this is due to the mass air flow sensor.
Because the air flow sensor is playing important role in maintaining the proper balance of air and fuel inside the engine, its failure can cause a number of problems with the performance of the power unit. These may include low mileage after refueling, shuddering when the engine is running, problems starting the engine, knocking or noises. These signs may appear much earlier than the mass air flow sensor reaches a critical state and the indicator on the dashboard lights up indicating a breakdown.
Sometimes the mass air flow sensor becomes dirty and therefore begins to work poorly. Even though the air passing through the mass air flow sensor cleans it, microscopic particles of debris accumulate on its internal surfaces. Large accumulations of pollutants lead to damage to the device. In this case, the part can be returned to its original condition by simple cleaning. However, it is worth remembering that the sensor is a very delicate device and careless handling can cause it to become completely unusable.
There are other malfunctions of the mass air flow sensor. For example, if everything is fine with the device itself, the corrugated wire that connects it to the on-board computer may become unusable. As a result, the signal will be sent to the central processor late, which will negatively affect the operation of the engine. To make sure it is working, you need to ring the wire or other similar device.
Diagnostics
A car mechanic can check the on-board computer at service center. You can also do this yourself using a digital scanner for diagnostics. These scanners are available at most auto parts stores. While they all work a little differently, they are generally designed to connect to a vehicle's OBD-II diagnostic port. Therefore, all scanners can read data from a computer.
After checking, the scanner will show one or more alphanumeric codes, which can be found using the reference book. More advanced models display brief information about the code on the screen. If, after decoding, it becomes clear that the malfunction is related to the mass air flow sensor, then it must be replaced or repaired. It is worth noting that mass air flow sensors are rarely repairable, since they are easier and cheaper to simply replace.
The video shows the symptoms of a faulty mass air flow sensor on a VAZ. A non-working mass air flow sensor was specially installed:
Mass air flow sensor design
Signs of a malfunctioning mass air flow sensor can be direct or indirect. Let's consider everything possible options:
- . In most cases, the CHECK indicator lights up due to the failure of one of the sensors, so you need to connect to to accurately determine the malfunction.
- Power drop is only an indirect sign, since there may be another reason for this malfunction.
- Increased fuel consumption . Of course, everything can be attributed to the fuel pump, but the fuel pressure sensor must also be checked. .
- Reduced acceleration dynamics . An incorrect amount of air mixture that enters the combustion chambers produces a poor ignition mixture, which in turn does not give and leads to.
- Poor or inability to start . Rich or cannot detonate normally, which will lead to just such problems. It is also possible that fuel does not burn out and...
- . Different amounts of air entering fuel mixture will give an effect when the speed will either decrease or increase.
To accurately determine the malfunction of the DMVR sensor, it is necessary to diagnose it.
How to check the MAF sensor?
The mass air flow sensor is checked using a multimeter
The mass air flow sensor is quite easy to check. For diagnostics you will need a multimeter.
Voltage readings of a working and faulty sensor
- 1.01-1.02 - readings from the new sensor, everything is normal.
- 1.02-1.03 - there is wear, but the parameters are within normal limits.
- 1.03-1.04 - the parameters are working, but there is already wear.
- 1.04-1.05 - critical parameters, get ready for replacement, if you have the money, then we’ll change it. Fuel consumption may be reduced.
- 1.05 and higher- the MAF sensor is not working.
Measurement using paper clips - there may be an error on the device. According to the readings, it is clear that the sensor “ordered to live long”
Alternative verification method
The second way to check the performance of the mass air flow sensor is to disconnect the power from it and drive a few kilometers. If engine performance has improved, then the problem is in the mass air flow sensor.
conclusions
It is quite easy to determine the malfunction of the mass air flow sensor VAZ-2112 16 valves. To do this, you need to know the direct and indirect reasons that contribute to the diagnosis, as well as carry out testing in the most basic ways.
An air flow meter or mass air flow sensor is a device that measures the amount of air entering the engine cylinders. There are several varieties of them, which differ in the method of measurement. An earlier design is a pitot tube flowmeter (called a vane type). The principle of its operation is based on measuring the deflection of a special plate by the air flow, on the axis of which a potentiometer is installed. The device resembles a throttle valve. Depending on the speed of the air flow, the angle of rotation of the plate changes, and accordingly, the electrical resistance of the potentiometer.
More modern designs flow meters have a hot-wire air flow meter. The principle of its operation is as follows. In the air flow there is a heat exchange element in the form of a platinum wire. The stronger the air flow, the more electricity must be supplied to it in order to maintain a given temperature difference between the wire and the air flowing around it. To remove deposits on a platinum wire (diameter approximately 0.07 mm), a self-cleaning mode is provided, in which, after stopping the engine, which has been running for some time under load, it is briefly heated to a temperature of 1000-1100 ° C.
The most modern flow meters are hot-wire anemometers with a film meter. Their heating and measuring resistors are made in the form of thin platinum layers deposited on the surface of a silicon crystal.
Flow meters with vortex-type meters are also available. The principle of their operation is based on measuring the frequency of vortices that appear at a certain distance behind the protrusion in the wall of the intake channel. It is worth noting that many modern foreign cars use a sensor instead of an air flow meter absolute pressure in the intake manifold.
Types and causes of malfunctions
Each flowmeter design has its own characteristic faults. For “blade” type flowmeters, this is wear of the current-carrying surfaces of the potentiometers and the formation of oily deposits on the working elements. Wear of the potentiometer (“cut” of the current-carrying path) leads to periodic loss of the electrical signal, as a result of which distorted data is transmitted to the control unit. Oily deposits and oxide on the surface of the channel interfere with the movement of the valve (it jams). In the case of hot-wire flowmeters, the cause of the malfunction may be the lack of power supply from the vehicle’s on-board network, as well as unqualified maintenance of this unit. Even attempts to wipe its working surfaces with cotton can damage the flow meter. This unit is not serviceable and cannot be repaired. You can only check the reliability of the contact connections, and in case of contamination, blowing with compressed air or washing the working surfaces with special preparations can help.
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Diagnostics
The flow meter is located between the air filter and the throttle valve.
Except external signs During engine operation, a faulty air flow meter can be reported by the built-in diagnostic system. Unfortunately, without diagnostic equipment, it is not always possible to read error codes and determine why the Check Engine warning light is screaming, so you need to contact a service station. You can verify that the air flow meter is faulty by replacing it with a known good one. If the result is an improvement - the reason is in the flow meter, there is no improvement - you need to look in a different direction. Very often, similar external manifestations are caused by air leaks through connections or cracks in the corrugated hose running from the flow meter to the throttle module.
Repair methods
By bending the plates, you can move the runner to the unworn part of the track.
Most often, they simply replace the faulty flow meter with a new one. Only flowmeters with a pitot tube (“blade” type) are repairable. Dirt and oily deposits that interfere with the movement of the plate are removed using
aerosols for cleaning the carburetor. Sometimes it is possible to restore the functionality of the potentiometer by moving its board with the contact track or bending the current collector plates so that the contact tip moves along the unworn part of the contact track. Sometimes technicians suggest disconnecting the flow meter from the electronic control unit. But in this case, fuel consumption increases noticeably. Hot-wire flow meters cannot be repaired in a car service center. They are restored only in a repair shop, for example Bosch.
Extending the resource
In order for the air flow meter to last longer, there are two means - change the air filter in a timely manner and monitor the technical condition of the engine (in some old power systems, where the hose of the crankcase gas suction system “cuts in” in front of the air flow meter). Engine repairs can also prevent premature failure of the flow meter, since wear of the piston rings and valve seals leads to an increase in the oil content in the crankcase gases, and this, in turn, causes clogging of the flow meter parts with an oily coating.
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From the article you will learn what the main symptom of a malfunctioning mass air flow sensor is. But before even visual diagnostics, you need to talk a little about what this device is, what its operating principle is, but the most important thing is to pay attention to maintenance and repair.
A mass air flow sensor is required for proper operation electronic control unit. Such systems are used only in injection engines. In other words, these are the majority of domestic cars that were produced after 2000.
Basic information about the mass air flow sensor
It is called MAF for short. It is with its help that all air that enters the throttle valve for mixture formation is measured. It sends its signal directly to the electronic control unit. This mass air flow sensor (signs of malfunction, Priora or another model are the same) is mounted directly next to the air filter. Or more precisely, between it and the throttle assembly. The design of this device is so “delicate” that it is necessary to measure only thoroughly purified air.
And now a little about how this sensor functions. Engine internal combustion performs cycles in such a way that during one working stroke it becomes necessary to supply gasoline and air to the combustion chamber of each cylinder in a strict proportion - 1 to 14. If this proportion changes, there will be a significant loss of internal combustion engine power or a significant excess consumption of gasoline. Only if you adhere to this proportion will the engine function in ideal mode.
Sensor functions
And it is with the help of the mass air flow sensor that all the air that enters the fuel rail is measured. It first calculates the total amount of air, then this information is digitally sent to the electronic control unit. The latter, based on these data, calculates the amount of gasoline that must be supplied for proper mixture formation. And it does this in the right proportion. At the same time, the mass air flow sensor responds to changes in engine operating mode literally instantly. And a sign of a malfunctioning mass air flow sensor is a longer response to pressing the accelerator pedal.
For example, you start pressing the accelerator pedal harder. At this moment, the flow of air into the fuel rail increases. The mass air flow sensor notices this change and sends a command to the electronic control unit. The latter, analyzing incoming data by comparing it with the fuel map, selects a normal amount of gasoline. Another case is if you are moving uniformly, that is, without acceleration or braking. Then very little air is consumed. Consequently, gasoline will also be supplied in small quantities.
Processes during engine operation
And now a little more about how all these processes occur in an internal combustion engine. This affects the work in many ways. elementary physics. For example, when you press the accelerator pedal, the valve in the throttle assembly sharply opens. The more it opens, the more air begins to be sucked into the fuel supply system.
Consequently, when you press the gas pedal, the load increases, and when you release it, the load decreases. We can say that the DMRV monitors these changes. It is worth noting that the main symptom of a malfunction of the mass air flow sensor is a decrease in the dynamic properties of the car.
Design Features
This is one of the most expensive sensors in the internal combustion engine control system. The reason for this is that it contains an expensive metal, namely platinum. The basis of the sensor is a plastic tube of a strictly defined diameter. It is located between the filter and the throttle assembly. Inside the case there is a thin wire made of platinum. Its diameter is about 70 micrometers.
Of course, it is very difficult to measure the passing air. In an internal combustion engine control system, air flow measurement is based on temperature measurement. The platinum wire is subjected to sudden heating. By how much its temperature drops in comparison with the set one, the amount of air passing through the sensor body is determined. Pay attention to the sign of a bad mass air flow sensor to know if it is OK.
Device maintenance
During operation of an engine with an electronic control system, the sensor still becomes dirty. To clean it, there is a special algorithm embedded in the control system. It allows you to heat a platinum wire in literally one second to a temperature of about a thousand degrees. If there was any dirt on the surface of this wire, it immediately burns without a trace. This is how to clean the mass air flow sensor. The signs of a malfunction, whether it is a Kalina or any other car, will be the same.
This procedure is performed every time you turn off the engine. The mass air flow sensor is very simple in design, and its operational reliability is high. However, it is not recommended to repair this unit yourself. If a breakdown occurs, then the best option you will turn to competent diagnosticians and mechanics.
Disadvantages of the node
Please note that if the sensor fails, it is most effective to replace it with a new one. It cannot be repaired, which is its main drawback, since the price of a new one is sometimes more than two thousand rubles. But there is another minor drawback, which lies in the principle of operation. Any mass air flow sensor has this drawback. Signs of a malfunction (diesel or gasoline in the power system) are discussed in the article.
It allows you to measure the volume of air that entered the throttle assembly. But for engine operation it is important to know not the volume, but the mass. Of course, to perform the conversion you will also need to know the air density. It is for this purpose that a measuring device is installed in the air intake, in close proximity to the sensor, which measures the temperature.
How to increase service life
Try to change the air filter on time, since the mass air flow sensor will not be able to work for a long time if dirty air passes through it. Washing the thread and all inner surface can be done using special sprays for carburetors. Just try to do everything carefully and avoid touching the spirals. Otherwise, you will end up with an expensive replacement of the air flow sensor. IN last years Instead of such a sensor, other designs are often used. This type of mass air flow sensor is used on some foreign cars. Symptoms of a Nissan malfunction are similar to those that occur on “tens” or “Prior”.
A pressure sensor is often installed to monitor the flow of air into the combustion chambers. To increase the service life of the mass air flow sensor, it is necessary to promptly replace the air filter, and also pay attention to the cylinder-piston group. In particular, excessive wear on the piston rings will cause the platinum wire to become coated with oil deposits. This will gradually lead to damage to the sensor.
Major breakdowns
You should know how to identify a faulty mass air flow sensor. The internal combustion engine constantly changes its operating mode. Depending on the speed and load, a different air-fuel mixture is required. To mix it properly, you need a mass air flow sensor. It is also called a flow meter.
As you already know, it allows you to determine and adjust the mass of air that enters the fuel rail of the injection system. If your mass air flow sensor is working in ideal mode, then this is a guarantee that the engine will function normally. Please note that such a device cannot be repaired, even if you have many tools and accessories.
Symptoms of malfunctions
And now a little about what symptoms occur when the sensor breaks down. Often, when this element fails, the engine begins to idle intermittently, its speed constantly fluctuating. When accelerating, the car begins to “think” for a long time, there is no dynamics at all. Often the crankshaft speed also decreases or increases at idle. And if you are lucky enough to turn off the engine, then starting it turns out to be very difficult, and sometimes even impossible. This means that the mass air flow sensor needs to be replaced. “Priora”, the faults of which are scanned by the ECU, will definitely give an engine error.
Please note that it is not necessarily the sensor itself that has failed. It is not uncommon to observe small cracks or cuts in the corrugation that connects the sensor to the throttle valve. If you suddenly see that the Check Engine light starts to light on the dashboard, and the above symptoms are also present, then you can say that the flow sensor has become unusable. But you shouldn't rely on this alone. It is advisable to conduct a complete engine diagnostics. It is worth noting that the symptoms of a malfunction of the mass air flow sensor are very similar to those that appear when the TPS breaks down, for example.