How to check the air consumption sensor (DMRV) - signs of malfunction and repair

In order to ensure the uninterrupted operation of any engine requires supplying a certain composition of air and gasoline. It is in this case that the DMRV sensor is used - the mass flow sensor. In another other, it is also called the "flow meter". It costs near the air filter and determines and adjusts the volume of the air mixture, which enters the engine cylinders. Here you can see that since the beginning of the 2000s, such sensors stopped for foreign production cars - instead, the pressure determiner is mounted. This happened due to the fact that the DMRV is a very gentle device and it can be easily deducted: from excessive effort or simply due to wiping the surface of the sensor surface. And the repair of the sensor is very problematic, so in most cases it has to be completely replaced.

What is the sensor of the DMRV

As it was written above, this device is necessary to measure the amount (consumption) of the air, which enters the motor. In this case, the sensor is not measured by the volume of air masses that pass through the engine. It estimates the mass of compressed air, which enters the unit of time. And it gives the result in kilograms per second. DMRV is used both on diesel engines and gasoline engines.

There are two types of such meters:

1. For installation on cars;
2. For industrial use.

Principle of operation of the sensor DMRV

The operation of the mass flow sensor, mounted on cars, is based on, all known, OhmA law.

The heated wire is calculated by the air mass, which entered the air system of the motor. If briefly, this device is an analogue of the anemometer (it measures the speed of the air masses). Contact will be heated from the air, as a result of which its resistance will change. This indicator will increase as the temperature of the wire measuring the electrical current flowing through the contact. If the air at the input passes the passage of the wire, then it will fall it and, as a result, the voltage will decrease. From what can be concluded - the resistance decreases when the air weight decreases, which at the moment came inside the engine. But it should be noted that the engine has the ability to control the entire measurement process. After the whole process is over, the electronic int order system sends a signal to the dashboard sensor and to the system management center.

In the event that air density increase (this may occur due to an increase in the density of air masses or the temperature of temperature modes), the volume of the measured air will not change. And this, in turn, will be the main indicator that there are large air masses, which exceed the standard indicator. This device in its characteristics is perfectly suitable in order to control the combustion of gasoline. Since this process will be directly dependent on a particular air flow, and not from the total amount of air in the engine system.

Causes of determining the malfunction of the DMRV sensor

If a malfunction was detected in the flow meter, this is first of all, literally immediately, it will be noticeably on the operation of the engine of your car. The main signs that the flow meter has failed will be the unstable operation of the engine at idle (the revs or the engine can be reduced simply). In addition, the fuel consumption will noticeably increase, the acceleration of the car will noticeably become worse, the engine will be difficult to "start" (even after it was recently "dug"), intermittent (noticeably high or very low) engine speed at idle. Well, the main and most common signs that the air flow sensor has failed that you will not be able to start the engine at all.

Sometimes it happens that directly the flow sensor itself will be in good condition, and the hose from the corrugation connecting the sensor with the throttle will be covered with cracks. If problems with a flow meter appeared on your car, then you will tell you the controller, which will give an error on the instrument panel. But in this case it is necessary to complete the engine diagnostics to determine the cause of the fault. And this can be done only at maintenance stations.

How to check the performance of DMRV on their own

There are options when the efficiency of this device can be checked on their own, and not to resort to that of the car mechanic. First, you can simply turn off the flow meter and try to start the engine of the car without it. At the same time, the controller will switch to the freelance operation mode, and the fuel mixture will be prepared according to the throttle valve. In this case, the tachometer should show more than 1500 rpm. Try riding a small distance by car. If you feel that the engine work is more balanced, then we can say that the air flow sensor is in good condition.

In addition, you can conduct an inspection of the sensor visually. Inspect the inner surfaces, both the sensor itself and the hose attached to it. It is necessary that the surfaces are dry, without mud, moisture and oil spots. Since the ingress of oil on the seducing elements of the device can lead to its malfunction, and it can get to the surface of the device if the oil level has become too large or the ventilation system clustered

When you start retrieving the mass flow sensor, do not forget that there is a sealing rubber ring, which does not allow the air mass suck. If this ring is not either stuck in the air filter housing, the flow meter grid will be covered with dust. This also can lead to the fact that the service life of the DMRV sensor is significantly reduced.

How to diagnose and subsequent repair of the DMRV sensor

How to check the air consumption sensor? This is not necessary in special equipment. An experienced driver will easily determine the malfunction in this hearing sensor.

What are the characteristic signs of damage to the DMRV sensor?

1. The engine at idle works unstable.
2. The dynamics of overclocking the car sharply fell.
3. If a serious malfunction occurred, the engine starts with great difficulty or it is generally impossible to start.

The main problem is that exactly the same signs of breakage exist at the instrument to control the air temperature, therefore it makes sense to check the operation of the engine of the car using special instruments. If the system functions in normal mode, then in the event of the standard air mass increased or suddenly jumped sharply, then it will immediately respond to it.

But if you see that the devices do not signal the malfunction, and the characteristic operation of the engine has changed (and not for the better), then you need to diagnose the engine yourself. The following is a step-by-step instruction, how to check the DMRV sensor using a multimeter or ADC:

1. It is necessary to take a multimeter and translate it into a voltmeter mode. Set the reading of 2 volts (diagnostics of the flow sensor).
2. Open the hood and find the sensor itself. In most cases, four wires will lead to it. The first, this is the input signal, the second - output voltage, the third is responsible for grounding the device, the fourth - connects the sensor to the relay.
3. Then, turn on the ignition, but the engine is not necessary. Connect the multimeter;
4. Diagnostics must be carried out like this: Red wire from multimeter Attach the sensor with a yellow wire, connect the wire to the green wire. It is desirable when connecting the wires to apply special clamps - this may affect the signal stability.
5. Watch out for the point of the multimeter.

If the DMRV sensor is repaired or it is necessary to replace it completely, then follow the order:

1. It is necessary to turn off the ignition of the car.
2. Take the right size of the appropriate size (most often it is a 10 key) and remove the incoming air hose;
3. Remove the device, clean it or replace the new one.

The installation of the new sensor occurs in the reverse order, but must comply with some rules: first put on the instrument the sealing ring, then you need to check the sealing skirt and set the DMRV sensor into the air filter housing.

Good luck on the roads !!!

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