Remove dmrv what. Diagnosing and Troubleshooting the Mass Air Flow Sensor

Effective work engine depends on the quality of the incoming air-fuel mixture. In modern cars, the control unit calculates the amount of fuel needed depending on the amount of air that has entered the system. It receives this information from the air mass meter. If it is faulty, it will transmit incorrect readings that will affect the operation of the engine. The article deals with issues related to the DMRV: signs of malfunction, verification, repair and replacement.

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Symptoms

DMRV is located in the air duct near air filter. It is designed to determine the amount of incoming air. Depending on its readings, the control unit will show how much fuel is needed to form a high-quality fuel mixture. A ratio of 1:14 is considered normal. Therefore, the quality of the fuel-air mixture depends on the correct readings of the flow meter.

The high-quality work of the DMRV depends largely on the cleanliness of the air filter. Therefore, if symptoms of a malfunction of the DMRV appear, before making repairs, the air filter should be checked first. The flow meter is usually beyond repair. If it is defective, then it is changed to new device. But its cost is quite high, so you should first make sure that the causes of the problems are in the sensor, not in other machine malfunctions.

The signal for diagnosis is the following symptoms of a malfunction of the DMRV:

There are other symptoms of a sensor malfunction. For example, it may have cracks in the corrugated hose that connects the throttle to the sensor. If the engine stalls, there may be a power problem or damaged wiring. This is a signal to check the wiring. If a malfunction is found, the electrical system of the machine must be repaired.

In addition to the above signs, it is necessary to diagnose the level of the sensor signal.

A low signal level can mean the following:

Do not draw conclusions about the malfunction of the mass air flow sensor, relying only on the symptoms listed above. A complete diagnosis of the engine and machine should be carried out, since signs of a flow meter breakdown may appear when other devices malfunction. Then you need to repair these devices in order to restore the performance of the car.

Check and repair

There are five ways to check the MAF.

Method number 1. Checking the performance when the air flow meter is turned off. The method consists in disconnecting the sensor from the vehicle's fuel system and checking the system's performance without it. To do this, disconnect the connector of the device and start the engine. Without DMRV, the controller receives a signal to switch to emergency operation. It prepares the air-fuel mixture only based on the throttle position. If the car moves “faster”, does not stall, then the device is faulty and needs to be repaired or replaced.

Method number 2. Flashing. If the standard firmware has been changed, then it is not known what reaction the controller has in it in case emergency. In this case, try to put a 1mm thick plate under the throttle stop. Turnover should increase. Now you need to pull the chip from the air flow meter. If a power unit will continue to work, then the cause of the malfunction is the firmware.

Method number 3. Install a known-good device and start the engine. If after replacement it began to work better, the motor does not stall, then the device needs to be replaced or repaired.

Method number 4. Troubleshooting by visual inspection. For this you need Phillips screwdriver unscrew the clamp holding the air collector corrugation. Then you need to disconnect the corrugation and inspect the inner surfaces of the corrugation of the air collector and sensor.

They must be free of oil and condensation, surfaces must be dry and clean. If you do not monitor the air filter and change it rarely, then dirt can get on the sensitive element of the sensor and cause it to break. This is the most common malfunction. Traces of oil may appear in the flowmeter when elevated level oil in the crankcase, and also if the oil deflector is clogged ventilation system crankcase. If necessary, clean the surfaces with special cleaners.

Method 5. Checking the DMRV with a multimeter. To do this, turn on the tester in the mode in which the constant voltage is checked. The limit value for measurements should be set to 2V.

Sensor pinout:

1. The wire yellow color located closer to the windshield. It serves as an input for the signal from the flow meter.
2. White-gray wire - sensor voltage output.
3. The black/pink wire leads to the main relay.
4. The green wire is used to ground the sensors, that is, it goes to ground.

Wires may be different colors, but their location is unchanged. To check, you need to turn on the ignition, but do not start the car. The red probe from the multimeter must be connected to yellow wire, and black must be connected to ground, that is, to the green wire. We measure the voltage between these two outputs. Multimeter probes make it possible to connect without disturbing the insulation of the wires.

On a new device, the output voltage is in the range from 0.996 to 1.01 V.

During operation, this voltage gradually increases and its value can be used to judge the wear of the flowmeter:

• if the sensor is in good condition, the voltage is from 1.01 to 1.02 V;
• in a satisfactory condition - from 1.02 to 1.03 V;
• the sensor resource ends if the voltage is in the range from 1.03 to 1.04 V;
• a near-death state is indicated by a value ranging from 1.04 to 1.05, if there are no contraindications, then you can continue to use the sensor;
• if the voltage exceeds 1.05 V, the MAF needs to be replaced.

Diagnosis of the DMRV is not difficult and can be done by hand.

If there is dirt on the sensor, you can clean it yourself. You can use WD-40 to clean it. To clean the DMRV, you must first remove the pipe from it, and then dismantle the device itself. Inside the device there is a mesh and several wires - sensors.

They need to be sprayed with a cleaning agent and cleaned. Then let the liquid dry. If dirt remains, then the procedure should be repeated. With the same tool you need to clean the pipe. It must be free of dirt and oil stains. After replacing the air filter, all parts must be returned to their place. After the cleaning procedure at 80%, you can restore the device to work, the error about the low level of the sensor signal disappears (the author of the video is Alexey Romanov).

Flushing the sensor will help avoid costly repairs.

Replacing the DMRV

To replace the sensor with your own hands, you need to prepare a curly screwdriver and a key to "10".

The replacement procedure consists of the following steps:

Thus, if the machine stalls, has all the signs of a breakdown of the DMRV, then before starting its repair, you should check the level of its signal, it should not be low, perform a complete diagnosis of the machine and repair all faulty components and parts.

It is important to have your car checked regularly and on time. Maintenance, then parts and assemblies will last longer.

Video "Checking the MAF with a multimeter"

This video from the Simple Opinion channel demonstrates how to check the MAF with a multimeter.

From the article you will learn what is the main symptom of a malfunction of the mass air flow sensor. But before even making visual diagnostics, you need to talk a little about what this device is, what its principle of operation is, but the most important thing is to pay attention to maintenance and repair.

A mass air flow sensor is required for correct 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 abbreviated as DMRV. It is with its help that all the 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 (symptoms of a malfunction, Priora or another model, are the same) is mounted directly next to the air filter. And more precisely, between it and the throttle assembly. The device of this device is so "gentle" that with its help it is necessary to measure only thoroughly purified air.

And now a little about how this sensor works. Engine internal combustion performs cycles in such a way that in one working cycle it becomes necessary to supply gasoline and air to the combustion chamber of each cylinder in a strict proportion - 1 to 14. In the event that this proportion changes, there will be a significant loss of internal combustion engine power or a significant overrun of gasoline. Only if you adhere to this proportion, the engine will function in an ideal mode.

Sensor functions

And it is with the help of the DMRV that all the air that enters the fuel rail is measured. He first calculates the total amount of air, then this information in digital form goes to the electronic control unit. The latter, based on these data, calculates the amount of gasoline that must be supplied for proper mixing. And it does it in the right proportion. At the same time, the mass air flow sensor responds to a change in the engine operating mode literally instantly. And a symptom of a malfunction of the mass air flow sensor is a longer response to pressing the accelerator pedal.

For example, you start to press the accelerator pedal harder. At this point, the air supply to the fuel rail increases. The DMRV notices this change and sends a command to the electronic control unit. The latter, analyzing the incoming data by comparing them with the fuel map, selects the normal amount of gasoline. The other case is if you are moving uniformly, that is, without acceleration and deceleration. 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 take place in an internal combustion engine. Here, elementary physics largely influences the work. For example, when you press the accelerator pedal, the damper in the throttle assembly opens sharply. The more it opens, the more air begins to be sucked into the fuel supply system.

Therefore, when you press the gas pedal, the load increases, and when it is released, it decreases. We can say that the DMRV is following 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 base of the sensor is plastic tube strictly defined diameter. It is located between the filter and the throttle assembly. Inside the case is a thin wiring 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 rapid heating. By how much its temperature drops in comparison with the set one, the amount of air passing through the sensor housing is determined. Pay attention to the MAF sensor symptom to know if it is OK.

Device maintenance

During engine operation with electronic system control sensor is still dirty. To clean it, there is a special algorithm embedded in the control system. It allows you to warm up the platinum wire in just one second to a temperature value 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 the mass air flow sensor is cleaned. The signs of a malfunction, whether it is Kalina or any other car, will be the same.

This procedure is carried out every time after you turn off the engine. The DMRV is very simple in design, and its reliability is high in operation. However, it is not recommended to independently repair this unit. If there is a breakdown, then the best option there will be an appeal to competent diagnosticians and locksmiths.

Node Disadvantages

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 is the principle of operation. Any mass air flow sensor has such a disadvantage. Symptoms 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 has entered the throttle assembly. But for the operation of the engine, it is important to know not the volume, but the mass. Of course, to perform the conversion, you also need to know the air density. It is for this purpose that a measuring device is installed in the air intake, in the immediate vicinity of the sensor, which measures the temperature.

How to increase service life

Try to change the air filter in time, as the DMRV will not be able to work for a long time if dirty air passes through it. Flushing the thread and all inner surface can be carried out using special sprays for carburetors. Just try to do everything carefully, do not touch the spirals. Otherwise, you will end up with an expensive replacement of the air flow sensor. AT last years other designs are often used instead of such a sensor. Used on some foreign cars such a mass air flow sensor. The symptoms of a Nissan malfunction are similar to those that occur on the "dozens" or "Prior".

Often a pressure sensor is installed, with the help of which the incoming air into the combustion chambers is monitored. To increase the service life of the DMRV, it is necessary to replace the air filter in a timely manner, 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. oil soot. Gradually, this will lead to damage to the sensor.

Major breakdowns

You must know how to identify a malfunctioning mass air flow sensor. The internal combustion engine is constantly changing its mode of operation. Depending on the speed and load, a different air-fuel mixture is required. To mix it properly, you need a DMRV. 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 perfect 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 fixtures.

Fault symptoms

And now a little about what symptoms occur when the sensor breaks. Often, when this element fails, the engine starts to work intermittently at idle, its revolutions constantly fluctuate. When accelerating, the car begins to “think” for a long time, there is absolutely no dynamics at all. Often, the crankshaft speed also decreases or increases at idle. And if you were lucky enough to turn off the engine, then it turns out to be very difficult, and sometimes even impossible, to start it. So the mass air flow sensor needs to be replaced. "Priora", the malfunctions of which are scanned by the ECU, will definitely give an engine error.

Please note that the sensor itself is not necessarily out of order. It is not uncommon to see small cracks or cuts in the corrugation that connects the sensor to the throttle valve. If you suddenly saw that the Check Engine light started to burn on the dashboard, and the above symptoms are also present, then we can say that the flow sensor has become unusable. But don't rely on this alone. It is advisable to carry out a complete engine diagnosis. 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.

Road transport is constantly improving. All improvements made to the design of the car are aimed at improving various indicators - increasing power, reducing fuel consumption, improving aerodynamic performance and the level of overall comfort.

It looks like a new mass air flow sensor

One of the main improvements in terms of reducing fuel consumption was the transition from using a carburetor power system in favor of an injection system.

The use of a system in which the fuel supply is strictly dosed for the operation of the power plant in different modes makes it possible to reduce consumption while ensuring the maximum possible power output of the power unit.

But in the carburetor system, it is technologically simpler, since the work of the main element of this system, the carburetor, is performed mechanically, which provides high reliability. Also in this power system, the air-fuel mixture is formed in the carburetor and enters the cylinders due to the vacuum created by the pistons.

The injection system is technically more complicated. The working mixture is already formed in the cylinders, and the components of the mixture are fed into them separately. Air - one of the elements of the mixture, is supplied due to rarefaction, but the fuel enters the cylinders forcibly by injectors.

Behind right amount the fuel required to supply the cylinders is answered by the electronic control unit. But in order to correctly dose, the control unit must know such parameters as the position of the crankshaft and its speed of rotation, the amount of air entering the cylinders, the amount of air remaining in the exhaust gases, and the position of the throttle valve. These parameters for calculating the amount of fuel supplied correspond to the sensors installed in certain elements of the power plant.

Mass air flow sensor. Types

Consider, responsible for providing information on the amount of air received - a mass air flow sensor (DMRV, air flow meter).

Schematic arrangement of the air flow meter

The DMRV is always located in the air pipe, next to the air filter, its task is to determine the air flow at the outlet of the filter. There are several types of mass air flow sensors.

1. The first air flow meters were based on the Pitot tube, their second name is vane flow meters. The main element of such a sensor was a thin plate, softly fixed. The air flow, in the path of which the sensor is standing, begins to bend the plate. The potentiometer included in the circuit measures the degree of bending of the plate, while the resistance of the potentiometer changes - it is the change in the resistance of the potentiometer that acts as a signal for the amount of air supplied to the control unit.
2. More modern and most common are sensors using plate hot-wire meters. In such a flowmeter, the main element is a heat exchanger with two thin platinum plates. Energy is supplied to these plates for heating them, one of them is a working one, the second plate is a control one. The operation of the DMRV is based on maintaining the same temperature on both plates. It works like this: the air flow, passing through the heat exchanger, begins to cool the working plate. In order to maintain a temperature on the working plate identical to the temperature of the control one, large quantity current. The change in the amount of current also acts as an indicator for the control unit about the amount of air entering the system.
3. The third type of mass air flow sensors are flow meters, which use film meters. They use platinum-coated silicon wafers as working elements. DMRV data appeared relatively recently, so they have not yet received wide distribution.

Video: Cleaning the DMRV How to properly remove and clean the DMRV Everything in detail

Symptoms of a malfunctioning mass air flow sensor

The performance of the mass air flow sensor plays a significant role in the correct mixing of the air-fuel mixture. Therefore, its malfunctions lead to a malfunction of the installation or, in some cases, the impossibility of starting the motor.

The output and failure of this sensor can be identified by the following signs:

• the “Check engine” signal lights up;
• increase in gasoline consumption;
• power drop;
• decrease in speed gain dynamics;
• difficulty starting or inability to start;
• floating speed at idle.

But such signs are not only a signal of a breakdown of this sensor, there may be other reasons. Therefore, it is necessary to determine whether this is really "jumping" the DMRV.

Checking the air mass meter

One way to check the air flow sensor

There are several ways to troubleshoot this sensor. by the most in a simple way is to disconnect the power supply from the sensor on a running engine. After turning off the chip, the control unit goes into emergency mode, in which the fuel is dosed according to the readings of the throttle position sensor. At the same time, the idle speed will begin to increase to over 1500 rpm, although not always, some injection systems do not increase the speed.

When the flow meter is off, you need to drive a car. If the operation of the power plant has improved, most likely there are problems with the DMRV.

Something else useful for you:

Video: Demonstration of a faulty DMRV on Kalina, Prior, Grant, VAZ 2110-2112, 2114-2115

Some sensors can be checked with a voltmeter or multimeter with high tuning accuracy. Measuring device The “positive” probe is connected to the DMRV signal wire (usually the rightmost wire), and the “negative” probe is connected to the sensor ground wire. Then you need to turn on the ignition, but do not start the power plant. For a working sensor, the voltage should be from 0.9 to 1.4 V. The indicators above indicate a malfunction of the DMRV.

Very often, the failure is the contamination of the working elements of the sensor. So visual inspection may also indicate a problem.

If on the working elements of the DMRV it is noticeable heavy pollution, this is probably the cause of problems with the operation of the power plant. That's just the restoration work can be done with sensors based on the Pitot tube. Dirt can be removed from them by washing with a carburetor cleaning spray.

Sensor replacement

Removing the Mass Air Flow Sensor

If the check indicated a malfunction of the DMRV, it is replaced, since they are non-repairable. Replacing it is very simple. Using an example, we will analyze the replacement of the sensor with a VAZ-2110.

All replacement work is carried out with the ignition off. First, a chip with wires going to the sensor is disconnected from the sensor.

Then you need to loosen the clamp securing the inlet pipe to the filter, after which the pipe is disconnected from the filter.

A 10 wrench unscrews the two bolts that secure the sensor. Now the DMRV can be removed from the seat.

Before installing a new sensor in seat it is important to check the tightness of the sealing ring, otherwise, if the density is insufficient, there is a possibility of air leakage, and not purified from impurities, from the outside. And this can lead to a quick breakdown of the sensor.

After checking the seal, the DMRV is put in place and fixed with bolts. Next, put the pipe in place and connect the chip with wires.

The final step is to verify the recovery normal operation power plant.

The operating mode of the internal combustion engine is determined by many factors - the load on the engine, the condition of the road, the load of the car, etc. motor to work in optimal conditions a strictly defined ratio of gasoline and air is required. The amount of the latter is determined by the DMRV (mass air flow sensor), it is under it that the engine control controller calculates how much gasoline is needed. A sensor malfunction disrupts the operation of the motor, and often the problem arises of how to check the DMRV in order to establish a final diagnosis.

DMRV malfunction, symptoms

The fact that a DMRV check is needed can be determined by outward signs engine operation. Symptoms indicating that at least the performance of the mass air flow sensor needs to be checked are as follows:

• the Check Engine banner appears on the instrument panel;
• increases the consumption of gasoline;
• the dynamics disappear when the car is moving, the car “dulls”;
• hot engine does not start;
• motor power is lost.

The described symptoms of a malfunction of the DMRV are not exhaustive. All violations in the modes of normal engine operation may be evidence that the DMRV needs to be checked.

What can cause a malfunction of the mass air flow sensor

When the introduction of injection into almost all cars has passed, the presence of a DMRV in them can be considered mandatory. According to various estimates, today there are more than fifty various types mass air flow sensor. Each of them uses its own measurement principle, especially since there are variety of options methods for measuring mass air flow.

It should be noted that all of them are based on the operation of sensitive elements and sensors, which are often quite complex and designed to work under certain conditions. Therefore, a change in these conditions, the appearance of additional factors, such as dirt on the sensing elements that enter with the air flow, causes, if not a malfunction, then at least distorts the DMRV readings.

This is also evidenced by the condition of the inner surface of the air duct and the air filter. Often oil gets there through crankcase ventilationcausing malfunctions of the sensor. Therefore, if the DMRV diagnostics shows its malfunction, then sometimes it is enough to clean and flush the sensor to restore its performance.

How to determine the malfunction of the DMRV

Checking the DMRV, which allows you to determine its malfunction, can be performed in several different ways.

To do this, the multimeter control panel is set to measure the DC voltage at the limit of two volts. In the sensor connector, connect to the yellow and green wires. These will be the first and third pins of the connector (windshield side). The colors of the wires may be different, but the numbering of the contacts will be the same.

The ignition is turned on, but the engine does not start, and the DMRV readings are checked. The new sensor has a voltage of (0.996-1.01) V. The larger its value, the worse the state of the MAF. Exceeding the voltage of (1.03-1.04) V indicates that the sensor is in a dying state, and the voltage is greater than 1.05 V, which means that it is time to throw away the mass air flow sensor and install a new one.

The video shows in detail how to check the sensor. It should be noted that in some models, the on-board computer generates voltage at its output.

Cleaning the Mass Air Flow Sensor

The DMRV is not repaired, but it can be cleaned. This is done by flushing the sensor. The attitude to this procedure is far from unambiguous, according to some, such cleaning only kills the sensor, others argue that flushing allows you to restore its performance. In any case, there is ample evidence that properly performed cleaning allows you to operate the DMRV further and avoid costly replacement.

Most likely, everything is determined design features sensor and correct execution works. In any case, when cleaning is carried out, you can not use:

1. ethers;
2. compressed air;
3. cotton buds;
4. acetone.

Again, according to various reviews, carburetor cleaning fluid or WD 40 is used for these purposes. How cleaning is carried out is shown in the video

The DMRV is an integral part of a modern car, and the operational parameters of your car largely depend on it. You can check its performance in several ways, including using an external multimeter. This makes it possible to accurately estimate Current state and take the necessary action.

The video shows the symptoms of a faulty DMRV sensor on a VAZ. A non-working DMRV was specially installed:

Mass air flow sensor device

Signs of a malfunctioning mass air flow sensor can be direct or indirect. Let's consider everything possible options:

1. . In most cases, the CHECK indicator lights up due to the failure of one of the sensors, so you need to connect to in order to accurately determine the malfunction.
2. Power drop is only an indirect sign, since there may be another reason for this malfunction.
3. Increased fuel consumption . Of course, everything can be attributed to the fuel pump, but the DMVR must also be checked. .
4. Decreased acceleration dynamics . The wrong amount of air mixture that enters the combustion chambers gives a bad incendiary mixture, which in turn does not and results.
5. Bad start or its impossibility . Rich or can not detonate normally, which will entail just such problems. And it is also possible that the fuel does not burn out and.
6. . A different amount of air entering the fuel mixture will give an effect when the speed will either decrease or increase.

For exact definition malfunction of the DMVR sensor, it is necessary to diagnose it.

How to check the MAF sensor?

The mass air flow sensor is checked with a multimeter

The mass air flow sensor is fairly easy to check. For diagnostics, you need a multimeter.

Voltage readings of a good and a faulty sensor

• 1.01-1.02 - the readings of 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 there is money, then we change. Fuel consumption may be reduced.
• 1.05 and above- non-working MAF sensor.

Measurement with paper clips - there may be an error in the device. According to the testimony, it can be seen that the sensor "ordered to live long"

Alternative way to check

The second way to check the performance of the mass air flow sensor is to turn off the power from it and drive a few kilometers. If the engine performance has improved, then the problem is in the DMRV.

findings

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 to check in the most elementary ways.