Signs and symptoms of a malfunctioning mass air flow sensor: self-diagnosis, cleaning and replacing the mass air flow sensor


01/25/2022 1,853 Electrical

Author: Victor

If the mass air flow sensor fails, the operation of the injection system will be disrupted, and therefore the functioning of the car’s engine as a whole. If signs of a malfunction of the mass air flow sensor appear, the easiest diagnostic method is to install a known working device instead of the controller.

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What is a mass air flow sensor and its purpose

In a car, this controller is a device used to estimate the volume of air that enters the engine. The sensor belongs to the class of regulators of the electronic control mechanism of the power unit. The first thing that the mass air flow sensor affects is the operation of the injection system. The device is designed to determine and regulate the air flow that enters the engine cylinders in order to form a combustible mixture. The controller in a car can be used in conjunction with air pressure and temperature sensors, which are used to change its readings.

Installation location

To save fuel, modern cars are equipped with injection engines with electronic ignition. In a simplified form, an injector is a point injection of a mixture through a nozzle into a cylinder or intake tract. The ECU control unit is usually called the “brains” of the car; it is this body that adjusts the four main parameters of the electronic control system (ECM):

  • injection frequency;
  • injection moment;
  • fuel mixture dose;
  • the ratio of fuel and air in it.

To obtain this data, the principle of remote sensors is used. For example, the moment of injection is determined by the readings of the crankshaft sensor DPKV, and the mass air flow sensor is responsible for the proportions of the mixture. All air entering the car engine passes through the throttle valve, which is located between the intake manifold and the air filter.


Rice. 3 VU meter location

Therefore, it is most logical to look for the mass air flow sensor directly in front of the throttle valve, where it is located

Attention: Information is transmitted to the controller from seven sensors: camshaft DRV, detonation DD, lambda probe, throttle valve DPZ, cooling system DTOZh, volume meter DPKV and crankshaft DPKV. Based on these signals, the ignition module is turned off, the fuel pump and injectors, the fan and the idle regulator are turned on.

Principle of operation

The principle of operation of the mass air flow sensor can be based on counting Kraman vortices or shifting the potentiometer slider by means of a blade mounted on the air supply flow.

The first option is considered more reliable, since it is not equipped with moving structural elements. In this case, the device counts Kraman vortices appearing in laminar air flow. On the way of the latter, special obstacles with sharp edges are used as resistance. An air flow breaks off from them, which linearly depends on its speed. This type of controller only works if there is turbulence in the air.

If the air speed is too high, it can lead to the formation of parasitic pressure pulsations. Therefore, the design of the devices is often supplemented with an input for changing the sensitivity of the measuring component. This may be required at low air flow rates when the power unit is idling. Vortex-type mass air flow sensors on older cars used two ultrasonic elements - a transmitter and a receiver. Then they began to use devices in which the function of measuring pulsations to count vortices is performed by a heating filament.

The StarsAuto channel talked about the design features, as well as the operating principle of automobile flow meters.

If the sensor is equipped with a measuring potentiometer, it operates on the principle of slider displacement. Its working blade is equipped with a spring and is installed in the flow of consumed air by the motor. If it increases, a proportional displacement of the blade occurs. The flow has a pulsating nature; accordingly, to reduce the effect of pulsations, the controller blade is connected to a damper. A potentiometer slider is also associated with it, which, when the sensor operates, moves to a level proportional to the volume of air flow.

This structural element is made on a ceramic surface where the resistor elements of the voltage divider are installed. Their leads are arranged in a row and covered with a special resistive layer. The device slider is pressed against the contact component. Due to this, the voltage level on it corresponds to the value at the point of contact with the resistive layer. If the blade changes its position, the elements move, which leads to abrasion of the slider.

Sensor restoration

Before starting work on the car, it is necessary to deactivate the ignition and disconnect the plug with wires from the regulator.

What will you need?

To carry out the procedure you will need:

  • rags;
  • set of wrenches;
  • cleanser;
  • a screwdriver if its use requires dismantling the flow meter.

Selecting a cleaner

Products that can be purchased at the store to clean the controller:

  1. WD-40. A universal product that can also be used for cleaning.
  2. Liqui Moly. The use of such a composition is relevant for working sensors. The product is universal and can be used on both diesel and gasoline engines.
  3. Alcohol.
  4. Cleaning agent for carburetor engines.
  5. Liquid key. This product is sold as a spray.
  6. Air Senso Clean.

Good to know

Do not use cotton swabs or compressed air to clean the device. It is important that the cleaning agent does not contain acetone or ether.

Algorithm of actions

ImageStep

The user must remove the hose connected to the sensor; to do this, use a wrench to unscrew the screws securing the device to the air filter housing. The dismantling algorithm may differ depending on the design features of the car.

  1. The sensor is removed from the pipe and removed from the installation site. To dismantle VAZ vehicles, the user needs an asterisk key of the required size.
  2. To remove the flow meter, the user needs to unscrew the screws that secure it.

  1. The regulator is being cleaned; red arrows indicate the places that need to be treated with the product.
  2. Inside the sensor there is a film on which the regulators themselves, made in the form of a wire, are located. The elements are fixed using a special resin.
  3. The user must treat the sensitive element with a cleaning agent, then wait a few minutes until the product dries. The cleaning procedure can be performed several times depending on the contamination. For faster drying, you can use a compressor.

Design of the mass air flow sensor

Structurally, the mass air flow sensor includes six elements:

  • working board of the device;
  • plastic case;
  • radiator element;
  • sensitive component in the form of a wire or nickel network;
  • the pipe through which the air flow passes;
  • meshes at the outlet and inlet of the device.

Current must be supplied to the sensitive component, otherwise it will not be able to heat up. When the device is operating, the average filament temperature should be 75-100 degrees.

Photo gallery “Design of mass air flow sensor”


Filament device with circuit board inside


Film flow meter for cars

Where to buy car accessories

Spare parts and other products for the car are easily available for purchase at auto stores in your city. But there is another option that has recently received significant improvements. You no longer need to wait a long time for a parcel from China: the AliExpress online store now offers the opportunity to ship from transshipment warehouses located in various countries. For example, when ordering, you can specify the “Delivery from the Russian Federation” option.

Follow the links and choose:

DVR, Dual, 1080P, 4G, Android 8.1, 10-inchCharger with two USB ports, 5 VAUTOOL X95 car compass, horizontal inclinometer, speedometer
12V car heaterHD night vision camera with 360 degree viewing angleKaradar G820STR radar detector with GPS

The most popular DMRV malfunctions

The main signs of a malfunction of the mass air flow sensor:

  1. Problems with the flow meter can be reported by the Check Engine indicator, which appears on the dashboard inside the car.
  2. Depending on the type of device and machine, an icon may appear on the control panel indicating a low level of the air flow sensor signal.
  3. The power unit began to work intermittently. When the sensor is disconnected, the car stalls or the engine speed begins to jump up or down. The power of the internal combustion engine decreases, the car has difficulty accelerating, especially when moving uphill.
  4. Increased fuel consumption.
  5. When changing gears on the gearbox, the engine randomly stops.

A faulty sensor can be determined by the integrity of the housing. The presence of damage on it, as well as on the corrugated line, may indicate problems with the controller. We are talking about the pipe that connects the regulator to the throttle valve. If the engine randomly stalls during operation, this may indicate a malfunction in the power line.

If the air quantity and distribution control device is faulty, then the symptoms of the breakdown may be similar to errors in the operation of the air filter.

Reasons why the device fails:

  • the sensor is not connected to the machine's power supply;
  • break or damage to the power supply circuit;
  • malfunctions in the operation of the controller can be caused by malfunctions in the functioning of the engine control unit;
  • incorrect connection of signal cables or their breakage;
  • oxidation or damage to contact elements.

Symptoms of a problem


Considering the symptoms that indicate a malfunction of this sensor, one cannot help but mention the following:

  • The CHECK ENGINE controller is triggered;
  • At idle, uneven engine operation is noted;
  • There are problems with acceleration dynamics;
  • The engine runs at very high or too low speeds;
  • Increased fuel consumption is observed;
  • The engine does not start at all.

In addition, there are other reasons for the inoperability of this unit, in the presence of which checking the mass air flow sensor is not only desirable, but necessary. Most often, we are talking about cracks that form in the corrugated hose connecting the throttle module to the flow meter, problems with the power supply, or damage to the wiring of the sensor.

Diagnostics of mass air flow sensor

If there is no similar sensor, then there are other ways to check the performance of the flow meter:

  • visual diagnostics;
  • checking while driving;
  • determining firmware compliance;
  • diagnostics with a tester.

Visual inspection

Before checking the device using this method, it must be removed from its mounting location. To do this, the pipes are disconnected from the housing of the air filter element. The inside of the controller must be dry; traces of motor fluid and condensation are not allowed. Often the device breaks down due to non-compliance with the air filter replacement intervals, as a result of which dirt remains on the sensitive component. This leads to the controller giving incorrect readings.

If there are traces of motor fluid on the internal cavity of the controller, this indicates a high level of lubricant pressure in the power unit. The reason may be a clogged crankcase ventilation. When checking, you need to make sure that the sealing element is located in the right place where the corrugation is installed. This part may have become stuck in the air filter housing. With this problem, air leaks into the engine, which gets inside with dust and contaminates the regulator.

Diagnostics on the move

It is necessary to disconnect the plug with the power circuit from the sensor and start the engine, and then disconnect the block. The Check Engine indicator will appear on the dashboard. The minimum engine speed should increase to 1500 per minute. If the engine begins to operate more stably after turning off the device, this indicates a malfunction. The sensor needs to be replaced.

User Igor Belov spoke about several methods for diagnosing the flow meter, including checking while driving.

Compliance of the mass flow sensor with the ECU firmware

To check the firmware compliance, you need to take a 1 mm thick plate and place it under the damper stop, this will lead to a change in engine speed. Then the block with wires is disconnected from the controller. If the car engine does not stop, then the reason is the firmware of the microprocessor module, idle speed controller without a flow meter in emergency mode.

Checking the mass air flow sensor with a multimeter

For diagnostics, the ignition is activated, but the power unit does not need to be started. Use the contact of the red probe on the tester to touch the first cable (yellow), and the black one goes to ground (green contact). It is not recommended to use sharp objects for connection, as this will lead to errors in the readings. This diagnostic method will allow you to determine the voltage level between the conductors.

The status of the sensor will be determined by the following readings:

  • from 0.99 to 1.01 V - parameters of the new controller;
  • 1.01 - 1.02 V - the regulator is in excellent condition, no need to change;
  • 1.02 - 1.03 V - generally satisfactory condition of the device;
  • 1.03 - 1.04 V - the controller’s service life is almost exhausted, replacement will soon be required;
  • 1.04 - 1.05 V - the sensor is in unsatisfactory condition, it’s time to change the device.

Diagnostics by the tester may not be performed on all types of flow meters. The pre-diagnostic mode of the multimeter must be configured to measure the value of direct current and set the maximum parameter to 2 V. Four cables are connected to the controller, each of which is designated by a specific color.

Starting from the near conductor to the windshield:

  • the yellow contact is intended for input of a flow meter pulse;
  • a white or gray cable is used as the supply voltage output channel;
  • green contact is ground or ground;
  • The black cable, equipped with a pink stripe, is responsible for the output to the main relay.

The colors of the contacts on the mass air flow sensor may be different, but the arrangement of the wires is always identical.

The “Simple Opinion” channel talked about performing diagnostics on a flow meter using a tester.

WHY DO YOU NEED A MAF?

Crankshaft position sensor, testing methods, symptoms of malfunction, location

If you try to set fire to something in a chamber where there is completely no oxygen, then nothing will come of this idea. To maintain the combustion process, an oxidizing agent is needed, in our case O2. In an internal combustion engine, atmospheric air is used as an oxidizer, which contains oxygen. It is not enough to simply burn the fuel - it is necessary that it burns without leaving any residue.

The correct proportion of the fuel-air mixture is the key to maximum engine performance. The amount of air and fuel required for gasoline engines is determined to be 14.7 to 1 (by weight). A fuel-air mixture of this composition is called stoichiometric.

In modern engines, fuel dosage control is entrusted to a computer. To accurately determine the amount of fuel that an injector needs to inject, it needs data on the amount of air entering the engine intake manifold. DMRV is responsible for receiving this data.

OPERATING PRINCIPLE

The operation of the sensor is based on measuring the electrical power that is necessary to maintain the temperature of the heating element located in the housing. The incoming air cools the element in the sensor, and the internal combustion engine controller strives to maintain the temperature by supplying electric current.

The more air the sensor passes through, the more power is required to maintain its temperature. The power is converted into a signal that is received by the control unit controller. Based on the received signal, the ECU calculates the amount of fuel that the injector should supply to the intake tract.

The amount of air passing depends on the angle at which the throttle valve is open.

What to do if the MAF signal level is low?

When this problem occurs, diagnostics is performed:

  • the presence or absence of supply voltage, as well as the reliability of connecting the device to ground;
  • resistance level between contact element 5 (in the diagram) of the connector and ground, this indicator should be from 4 to 6 kOhm.

The problem may be:

  • poor quality contact;
  • incorrect wiring harness route;
  • wear or damage to the cable core or insulating layer;
  • poor connection of the device to ground;
  • connecting more powerful energy consumers to the block.

Device diagnostics includes the following steps:

  1. The quality of contact between pins 7 and 12 on the injection system connector, as well as the sensor, is checked. A visual check of the condition of the block is performed to ensure correct connection. The problem may be damage to the locks or the use of damaged contact elements. The connection quality of the conductor to the block may be poor.
  2. You need to make sure that the harness route is not broken. Problems may arise if the cable harness is laid close to high-voltage wires.
  3. The integrity of the harness is checked to ensure that it is not damaged. If the element is visually intact, you need to try to move it and at the same time monitor the readings of the diagnostic equipment.
  4. The air filter device is also checked for clogging. If required, it is replaced.

If you have a tester, you can check the serviceability of the mass air flow sensor as follows:

  1. The key is turned in the lock to turn off the ignition. It is necessary to disconnect the connector with wires from the controller.
  2. Then the ignition is turned on, but the power unit does not start.
  3. The tester is used to diagnose the voltage level between the contact elements on the connector. Between outputs 2 and 3 this value should be above 10 volts, between 3 and 4 - 5 V, and between ground and the third contact - 0 V. If the values ​​obtained are different, it is necessary to eliminate breaks in the line and get rid of the short to ground.
  4. Then the ignition in the car is turned off. Using a multimeter, you can diagnose the resistance level between the fifth contact and the ground on the block.


Connection diagram of the flow meter to the microprocessor

If the resulting value is about 4.6 kOhm, then the regulator itself is faulty. The problem may lie in its poor-quality connection. If the resistance level is 0 ohms, the problem is a short to ground of the fourth contact or a malfunction of the sensor. If the obtained value is more than 100 kOhm, this indicates a break in the 4G wire or a breakdown of the regulator.

What can break in the air flow sensor

  1. Trivial clogging of the flow meter. During severe operation in city mode or on dusty country roads, the air filter may not cope and allow the smallest particles to enter the channel. The sensors can be cleaned with compressed air or a special aerosol product if the problem is not severe.
  2. Ingress of return gases from the intake manifold (incorrect operation of the USR) onto the sensitive elements. The problem is typical for cars with a high Euro environmental class.
  3. Physical damage to the temperature sensitive element. It can deteriorate from normal wear and tear or from foreign objects (including oil or moisture). The element itself cannot be repaired (at least the labor costs are higher than the actual cost of a new AFMV). Therefore, it would be wiser to simply replace the entire flow meter.
  4. Mechanical damage to the body of the measuring channel (dents, cracks). Plastic can be restored if the internal geometry is not damaged. A similar “fault” is that the housing does not fit tightly to the air duct flange or throttle body.
  5. Destruction of the contact group (connector) or oxidation of contacts. The air flow sensor is installed in a place exposed to negative environmental influences (humidity, temperature changes, etc.)


    Broken contacts can be determined visually, or by ringing using a tester. If the contact group on the wiring harness connector is broken, it can be replaced. The contacts in the mass flow sensor housing are more difficult to restore. Oxidation can be eliminated by simple cleaning with a stiff brush. Then you need to apply a special lubricant to the contacts.

  6. Broken power or signal wire. Even a completely serviceable mass air flow sensor will not work if there is no contact or a damaged cable. The malfunction can be easily fixed using a soldering iron.

Tip: Do not twist broken wires together. In conditions of the engine compartment, such a joint will not last long.

What to do if the MAF signal level is high?

In case of this problem, you also need to check the presence of voltage on the power circuit and the quality of the connection of the sensor to ground. The parameter is also diagnosed on the fifth pin of the connector.

The check is done like this:

  1. The ignition is turned off. You need to disconnect the connector with wires from the device.
  2. The ignition turns on, the engine does not start.
  3. Using a multimeter, you can diagnose the voltage on the block. The readings obtained should be the same as when the sensor signal is low.
  4. Then the resistance is measured; the tester must first be configured in the appropriate mode. The measurement is made between the fifth contact element and ground. If the resulting value is 0 V, then the regulator is faulty and must be replaced. Other parameters will indicate a short circuit of the 4G conductor to the power source.

How to check the MAF sensor

You can detect and identify a problem in the operation of the sensor during self-diagnosis, when the error code is read by the system. Unfortunately, in most cases this is more difficult to do: the error is not detected in the memory of the car's control unit. In this case, you can check the performance of the mass air flow sensor in three ways:

  • Using a multimeter. It is believed that this is one of the easiest methods after self-diagnosis. Using a multimeter, you need to check the integrity of all wiring and each wire, and also look at the voltage on the signal wire;
  • Using a scanner. After connecting the scanner to the diagnostic block and control unit, you need to start the car. When evaluating, the sensor's analog-to-digital converter should show 0.996 V;
  • Using a motor tester. This is considered to be the most difficult method. It consists of recording the output signal when the ignition is turned on. If the sensor is working properly, the readings should show 3.11 V with a voltage surge.

It is much easier and more reliable to contact a nearby car service center, which has all the necessary equipment for an accurate check of the mass air flow sensor.

How to clean the sensor yourself?

By cleaning and flushing the air flow controller, you can restore its operation.

In particular, you will have to work with the sensitive element of the sensor - this part always becomes dirty during operation of the flow meter.

Selecting a cleaner

To complete the task you need to purchase a cleaning agent:

  1. Liquid Moly. This brand's mass air flow sensor cleaner is not cheap. But its use allows you to effectively remove contaminants and restore the operation of the device. The use of Liqui Moly cleaning products can be carried out on mass air flow sensors running on gasoline or diesel internal combustion engines.
  2. Technical or medical alcohol. This option is one of the oldest and most effective. The chemical properties of alcohol allow you to efficiently remove dirt from the sensitive part of the sensor.
  3. Carburetor engine cleaner. One of the most inexpensive and effective ways to restore the controller.
  4. Liquid key product. Allowed for use not only on mass air flow sensors, but also for cleaning other components and mechanisms.
  5. WD-40. Allows you to remove not only dirt, but also traces of rust.

Step-by-step instruction

Do-it-yourself repair of the mass air flow sensor is carried out as follows:

  1. Before removing the sensor, turn off the ignition and disconnect the terminal from the battery. In the engine compartment, the connector is removed from the flow meter.
  2. A pipe is connected to the device; it is also loosened and disconnected. Using a wrench, you unscrew the bolt that secures the mechanism to the air filter, in particular, to its body.
  3. The device is removed from the corrugation. Depending on the car model, this may require different tools, including star keys. The screws securing the device are unscrewed, and then the flow meter is removed from the landing site.
  4. If there are traces of oil on the device, they must be removed. To clean, use one of the products described above.
  5. The sensors themselves on the flow meter are usually made in the form of a wire located on a mesh. When using a cleaner, you must carefully treat the sensitive component. The film must not be damaged. When the area of ​​contamination is cleaned, you need to wait about 10 minutes for the product to take effect.
  6. If there is too much dirt on the device, then it is advisable to repeat the cleaning procedure several times. To ensure rapid evaporation of the product, you can use a compressor or pump. But too high a pressure can destroy the sensing element of the flow meter.

Photo gallery


Dismantling the flow meter


Cleaning with WD-40

Sensor malfunction

Like all devices, the sensor in question can fail. It is necessary to accurately establish that the cause of problems with the engine is precisely in it, and take appropriate measures.

Signs

A malfunction of the mass air flow sensor can be detected by the following signs:

  • Check engine error light is on;
  • gasoline consumption has increased;
  • power drops, the engine stalls;
  • speed gain decreases;
  • launch is difficult or impossible;
  • interruptions and rough operation of the engine at idle.

Important! In this case, it is worth contacting a service station to determine the cause of the breakdown, since the above symptoms may also indicate the presence of other malfunctions

Causes

Factors that cause DMRV malfunctions are the following:

  • air filter clogged. For this reason, the air contains many dirt particles that enter the sensor and cause its failure;
  • sometimes it happens that the sensor itself is working, but there are cracks in the hose connecting the mass air flow sensor with the throttle module;
  • Wear of the piston rings and seals is caused by excess oil in the crankcase gases. An oily film clogs the sensor.

Diagnostics

If you suspect a malfunction of the mass air flow sensor, it is necessary to check it:

you need to dismantle this device and carry out an external inspection

If the device is hot-wire, then care must be taken to ensure that the platinum threads are not damaged. A broken thread indicates that the sensor is faulty;

you can disconnect the power source from the sensor and start the engine

If the number of revolutions increases noticeably (often above 1500 revolutions), then this also indicates a malfunction of the device. It must be said that some injection systems do not increase speed;

Certain models of mass flow sensor can be tested with a voltmeter or multimeter. During normal operation, the voltage in it is in the range of 0.9–1.4 V. Higher readings indicate a malfunction of the device; Here's another way to simply determine the problem in this device - replace the sensor with a new one. If the machine works normally, then the reason is a malfunction of the old device. If nothing has changed, then the cause of the malfunction lies elsewhere.

We recommend that you learn how to choose the right spark plugs for your car.

Cleaning the air flow sensor

Different models of mass flow sensors should be cleaned differently. Let's look at the cleaning process using a VAZ car as an example. To carry this out, the following actions are recommended:

  • turn off the ignition;
  • disconnect the pipe;
  • loosen the air filter with sensor;
  • There is a part on the device that is bolted to it. You need to unscrew them with the appropriate keys;
  • Gently spray the cleaning agent inside onto the sensitive element from the syringe. Any strong impact can damage the sensitive element, so this procedure must be done as carefully as possible;
  • you can also wash the contacts of the block;
  • let dry thoroughly;
  • fasten everything back in reverse order.

Video: cleaning the mass air flow sensor

How to replace

The mass air flow sensor cannot be repaired: if it is faulty, it must be replaced with a new device. Replacing the sensor yourself is quite easy - it does not require any special skills.

Did you know? The oldest, but still driving car, moves on steam traction.
It was produced in 1884 and is named "La Marquise". In 2011, it was bought at auction by an unknown buyer for more than $4 million.
Let's consider replacing the sensor using the example of a VAZ car. To do this you need to do the following:

  • First of all, you should check that the ignition is turned off;
  • disconnect the chip with wires from the device that connects the sensor to the power source;
  • loosen the clamp securing the inlet pipe to the filter, and then disconnect the pipe from the filter;
  • Use the appropriate keys to unscrew the bolts securing the device;
  • carefully remove the device from its mounting location;
  • before attaching a new DMVR, it is necessary to check the fit of the seals, since with poor density, the likelihood of air leaking from outside increases, which is not cleared of impurities, which can cause failure of the device;
  • install the DMVR at the mounting location and secure it with bolts;
  • put the pipe in its original place and connect the chip with wires;
  • check engine operation.

Video: replacing the mass air flow sensor

Improper maintenance of the DMVR and its breakdown can cause interruptions in engine operation. In the event of a breakdown, it is quite possible to replace this sensor yourself.

Do-it-yourself replacement of the mass air flow sensor

If repairing the device does not help, then it will have to be replaced; you can perform this task yourself.

Step-by-step instruction

Replacing the mass air flow sensor is done as follows:

  1. The ignition is turned off and the engine compartment of the car is opened.
  2. The negative terminal is disconnected from the car battery; this is necessary in order to cut off the power supply.
  3. Using a screwdriver, loosen the clamp that secures the corrugation to the sensor.
  4. The pipe is removed.
  5. The power supply is disconnected from the flow meter.
  6. Using a wrench, unscrew the bolts securing the device to the filter element housing.
  7. The controller is removed and then replaced. All elements are subsequently assembled in reverse order.


Removing the sensor and replacing it

Signs and causes of malfunctions

If the flow meter partially fails, the driver will notice one or more of the situations listed below. In particular:

  • the engine does not start;
  • unstable operation (floating speed) of the engine in idle mode, up to its shutdown;
  • the dynamic characteristics of the car are reduced (when accelerating, the engine “fails” when you press the accelerator pedal);
  • significant excess fuel consumption;
  • The Check Engine light on the dashboard lights up.

The listed symptoms may also be the result of other malfunctions of individual engine components, however, among other things, it is necessary to check the operation of the air flow meter. Now let's look at the reasons why the described malfunctions occur:

Flow meter restoration

  • Natural aging and sensor failure. This is especially true for relatively old cars that have an original flow meter installed.
  • Motor overload. Due to overheating of the sensor and its individual elements, it may produce incorrect data for the ECU. This occurs due to the fact that when the metal is significantly heated, its electrical resistance changes, and, accordingly, the calculated data for the amount of air passing through the device.
  • Mechanical damage to the flow meter. It can be the result of various actions. For example, damage when replacing the air filter or other components close to it, broken contacts during installation, and so on.
  • Moisture getting inside the housing. The reason is quite rare, but it can occur if a large amount of water gets into the engine compartment for some reason. This may cause a short circuit in the sensor circuit.

As a rule, the flow meter cannot be repaired (except for mechanical samples), and if it fails, it must be replaced. Fortunately, the device is inexpensive, and the process of dismantling and installation does not take much effort and time. However, before replacing, it is necessary to diagnose the sensor and try to clean the sensitive element with carburetor cleaner.

Recommendations for extending the service life of the mass air flow sensor

The service life of the device is affected by the purity of the air flow that passes through it. Therefore, when using a flowmeter, it is necessary to prevent the formation of deposits on its working surface. To do this, it is recommended to periodically check the functioning of the air filter device. If necessary, the sensor must be changed regularly. If the car is operated in a large and polluted city, then the part must be replaced more often than indicated in the car maintenance regulations.

Cleaning the air flow meter

Since the manufacturers do not provide for repair of the mass air flow sensor, this electrical device is considered “consumable”. There is no consensus on the possibility of cleaning to restore performance, even among service station professionals. If the car owner nevertheless decides to clean the mass air flow sensor on his own, it is necessary to take into account the nuances of the technology:

  • the cleaner should not contain acetone or ether;
  • Cotton swabs and compressed air are prohibited;
  • most often WD-40 or Air Senso Clean from CRC is used;
  • After removing the device, the spray is applied to it evenly with a powerful jet, the dirt dissolves and flows off under its own weight.


Rice. 14 Cleaning the VU meter with spray

Installation of the mass air flow sensor in place is possible after drying the surfaces without using a hair dryer.

Video “Diagnostics and malfunctions of mass air flow sensor”

The 24 Hours channel spoke in detail about the signs of malfunction of flow meters and how to diagnose them yourself.

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Replacing the air flow sensor

It is important to know

The mass air flow sensor is purchased for a specific car model. The use of analogues is not recommended, as this may lead to malfunctions of the device.

What will you need?

To complete the task you will need:

  • key head with a knob;
  • Phillips screwdriver;
  • wrench 10;
  • new mass air flow sensor.

Step-by-step instruction

ImageStep

  1. The hood of the car is opened and the negative terminal is disconnected from the battery.
  2. The wires must be disconnected from the regulator; to do this, the user must press the pad lock from below.
  3. Using a screwdriver, loosen the clamp that tightens the air filter pipe.
  4. After loosening, the pipe must be pulled towards you and moved to the side.

The sensor is fixed with two bolts on the body of the filter device. To unscrew them, use a key or ratchet.
After removing the last fastening, the regulator is dismantled. A new sensor is being installed, after which a chip with wires must be inserted into the mass air flow sensor.
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