How to check the DMRV sensor in a Chevrolet Niva

March 23, 2017 Lada.Online 122 383 5

The MAF (mass air flow sensor) is designed to estimate the amount of air entering the engine of a fuel injected vehicle. Based on its data, the electronic control unit (ECU) adjusts the composition of the fuel-air mixture. Let's look at the features of checking the mass air flow sensor with a multimeter.

Operating principle of the sensor

There are two designs of the sensor:

Resistive is a classic potentiometer with a film track and a movable contact located on the rotation axis. As the slider moves along the track, the resistance changes. The ECU instantly receives information about the angle of rotation of the damper. Simple design, reasonable cost. The standard equipment of Niva Chevrolet engines is with exactly these sensors. The only drawback is that over time the tracks are erased, the TPS gives incorrect information or does not work at all. Requires regular replacement.
Non-contact magnetic sensor. Inside there is a magnetic field sensor and a microcontroller that converts information about throttle rotation into a format familiar to the ECU. This device lasts a long time, since it has practically no wearing parts, and gives more accurate readings. However, the complexity of the sensor in the presence of a microcontroller makes it dependent on operating conditions. For uninterrupted operation, a stabilized supply voltage is required. With a slight deviation, the electronics fail. Of course, the cost of such a device is somewhat higher than its resistive counterpart.

Principle of operation

The piston stroke occurs when fuel is burned with air in a ratio of 1:14, maintaining which ensures optimal operation of the power plant. When the proportion decreases or increases, the engine does not stop working, but there is excessive fuel consumption or a decrease in engine operating power. We need a mass air flow sensor so that air flows in portions. The operation of the unit proceeds as follows: the VAZ 2110 air flow sensor calculates the portion of fresh air, and then sends the data to the main computer, which, based on this information, calculates the portion of fuel.

The harder you push the gas, the more filtered air the powerplant requires. The mass flow sensor detects the increase and commands the electronics to increase the amount of fuel. When moving at the same speed, each portion should be equal to the previous one. The mass air flow sensor receives data on the load of the power unit, and then calculates the required portion of air. When the driver presses the pedal, the throttle valve opens, thereby increasing the volume of intake air - the load increases. When the pedal is released, the load drops.

Damaged sensor due to dust

Information about the operation and design of the mass air flow sensor

Again, we will not consider the historically outdated mechanical options with a weather vane and the General Motors frequency flow meter, which was used in conjunction with the January 4-series ECU. Modern flow meters for the VAZ 10 series operate on the principle of a hot-wire anemometer.

It is based on the properties of some metals to significantly change resistance depending on heat (the MAF sensor uses an alloy of iridium with platinum, which causes the high cost of the device). There are two resistors in the air flow: one is precision, the second can change the resistance using heat. Voltage is applied to it, the thread is heated until it matches the standard. Depending on the strength of the air flow, the thread cools and the resistance changes. By increasing the voltage across the resistor, the temperature and, accordingly, the resistance are restored. This happens in real time, that is, the control of the air mass is constant. At the output, the mass air flow sensor displays the signal voltage with an accuracy of hundredths of a volt. The received information is processed by the ECU to accurately dose gasoline into the fuel-air mixture.

All elements are arranged into a single electronic model, which is placed in the measuring channel (air duct).

Sensor device

View of the flow meter from the grid side.

The sensor is disassembled.

The platinum thread is visible in this photo.

Visual inspection

As for visual diagnostics, first of all it is necessary to check the condition of the corrugation in which the flow meter is installed, as well as the device itself. If, as a result of the check, you see traces of motor fluid or condensation, then it is possible that the device does not work for this reason. In some cases, cleaning the device from contaminants allows the flowmeter to resume operation and prevent possible replacement. It should be taken into account that contaminants usually accumulate as a result of infrequent replacement of the air filter element (the author of the video about the regulator malfunction is the channel In Sandro’s Garage).

Demonstration of a faulty mass air flow sensor on Kalina, Priora, Grant, VAZ 2110-2112, 2114-2115

If you notice traces of engine fluid, then there is a possibility that the reason lies in a clogged oil seal, or the problem may lie in exceeding the permissible level of lubricant in the crankcase. When cleaning is complete, you will need to make a visual inspection of the regulator - on the front of it you can see the rubber seal that is used for sealing. The seal is necessary to prevent uncleaned air flow and it may be that the rubber band moves a little - this will lead to the accumulation of dust on the flowmeter grid.

Throttle position sensor - TPS.

The function of this sensor is to provide information to the brain about the position of the gas pedal and the degree of throttle opening. The TPS contains electromechanical parts, that is, a potentiometer. This means that after some time it wears out and the sensor dies. In Russia there are about 10 companies producing this sensor

But I want to draw the reader’s attention to the so-called non-contact (inductive) TPS. It is made by one company that used to be a “mailbox”

My experience has shown that the sensor in their “non-contact” design is virtually eternal. This is exactly what is shown in the photo.

Video “Checking the mass air flow sensor using a multimeter”

This video from the “Simple Opinion” channel demonstrates how to check the mass air flow sensor with a multimeter.

For optimal operation of an injection internal combustion engine (hereinafter referred to as ICE), it is necessary to take into account how much air mixture enters the combustion chambers of the cylinders. Based on these data, the electronic control unit (hereinafter referred to as the ECU) determines the fuel supply conditions. In addition to information from the mass air flow sensor, its pressure and temperature are taken into account. Since mass air flow sensors are the most significant, we will consider their types, design features, diagnostic and replacement capabilities.

Signs and causes of malfunction of the Niva Chevrolet flow meter

Since the controller responsible for recording OBD-II errors on the Chevy Niva lights up the “Check Engine” lamp only after the complete “death” of the patient, it is better to know the symptoms of the malfunction yourself.

on an unheated engine, idle speed floats randomly;
when you press the accelerator all the way and suddenly release the gas, the rpm hangs at 1500;
starting a cold engine is difficult;
under load the car may stall;
When moving evenly, the engine jerks.

Why does the air flow sensor fail?

Natural demise does not occur quickly; under normal operating conditions, mass air flow sensors (especially BOSCH ones made in Germany) live and live for several years.

The quality of gasoline or the use of LPG does not affect them. All reasons are subjective, and are associated with the owner’s reluctance to invest in maintaining his car.

Problems with the air filter. It is this that is the source of contaminants that kill the sensitive elements of the flow meter. This item includes untimely replacement of the filter, crooked installation (presence of cracks), loose fit of the mass flow sensor to the flange of the filter housing. Separate items include zero-resistance filters and incorrectly installed snorkels (typical for ShNiva).
Water entering the air filter (after fording). The amount of liquid is not enough for water hammer, but droplets penetrate the air flow sensor and destroy the sensors.
Oil in the intake manifold. We are not talking about the USR (it simply isn’t there), if there are problems with the crankcase ventilation valve, oil dust easily penetrates into the air duct, right up to the air filter.

As a result, the flow meter looks something like this:

At best, it will not work correctly, at worst, it will quickly fail.

All these points can be forgotten if you check the car components in a timely manner during maintenance.

Suitable scanners for Chevrolet Niva

For diagnostics, reading indicators and errors, ELM327 automotive scanners are used - for ECUs with a CAN bus and VAG KKL and K-Line “laces” for earlier ECUs. For control units that operate using the OBD2 protocol with a CAN bus, the following scanners are suitable:

Typically, ECUs are of the Bosch brand and are found with the following catalog numbers:

21230-1411020-10-0 – BOSCH MP7.0 controller
21230-1411020-30-0 – BOSCH M7.9.7+ E3 controller
21230-1411020-40-0 – BOSCH M7.9.7+E4 controller
21230-1411020-90-0 – BOSCH M7.9.7+AC controller

Information about the type of controller and the firmware that is installed on it can be found on the sticker on the body of the control unit itself.

Determining fault codes on a Chevrolet Niva

Self-diagnosis via OBD1

On the Chevrolet Niva, the ECM unit with the BOSCH controller has built-in self-diagnosis, which detects and deciphers faults in electrical circuits. The ECM identifies the problem, then the “Check Engine” lights up - the presence of an error is identified, then the fault code is stored in memory and displayed on the dashboard.

Did the Check Engine light come on on a Chevrolet Niva?

Detailed article on the causes of Check Engine and how to clear the Check. If your Check Engine light comes on, read this article immediately. The material explains what a Check Engine is, what to do if it appears, and how to remove this error yourself.

Is the Check Engine light on?

TOP 15 reasons why the Check Engine light comes on and ways to solve the problem. Read the article to solve the Check Engine problem.

Reviews of diagnostic scanners for Niva Chevrolet

Read detailed articles on reviewing scanners for car diagnostics, including for the Chevrolet Niva.

Reviews of OBD2 diagnostic car scanners

This section provides descriptions of diagnostic scanners and adapters. Before purchasing a scanner for your car, it is recommended that you read reviews of the most popular equipment models.

Types and principle of operation of flow meters

The mass air flow sensor is a hot-wire device.

The main types that are used on cars:

Film with analog and digital signal.
Wire (thread) analog.
Frequency mass air flow sensor. Already installed on most modern cars coming off the assembly line.

Pitot tube (vane type) flowmeters are not considered due to their outdated design.

The operating principle of the first two types of devices is similar to each other and is based on changing the voltage readings supplied to the heating elements (threads or film). The ECU monitors these changes and performs calculations to form the fuel-air mixture. More details below.

Wire mass air flow sensor

Used on most modern cars. In such devices, the key role is played by thermistors - two tungsten or platinum filaments with a diameter of 0.07 mm, to which voltage is applied with a certain current strength, as a result they heat up, as well as a thermistor (temperature sensor), but it is not provided everywhere.

One thread is closed from the air flow, and the second, with the throttle valve open, on the contrary, is blown and actively cooled.

To equalize the temperature readings of thermistors, more current is supplied to the open thread.

The ECU takes into account the difference in voltage readings between the threads, the intensity of their cooling and, based on them, calculates the volume of incoming air and, in accordance with this, calculates the required amount of fuel supplied to the cylinders.

Wire mass air flow sensors have several significant disadvantages: over time they become dirty or wear out.

To solve the first problem, the designers developed a self-cleaning mode. It provides for a short-term (so as not to discharge the battery) heating of the filament to 1000-1100C with the engine turned off. At this temperature, all deposits burn out.

When the thermistors wear out, the sensor is replaced.

Film flowmeters

Structurally, such sensors differ from the first ones, although the principle of their operation is largely the same.

Instead of a sensitive thread thermistor, a platinum-coated ceramic heating element or semiconductor film is installed here.

The location of the film device remains the same, and the ceramic element itself has several resistor layers, each of which performs its own function: a temperature sensor, a heating one, two thermistors.

An important advantage of such a sensor is that it measures the temperature of not only the incoming air, but also the reflecting air. The device is also less susceptible to contamination.

It is worth noting that in modern devices, the output signal U is transmitted not only in analog mode, but also in digital mode, this speeds up data processing.

Frequency mass air flow sensor

The General Motors product was installed on the first VAZ 2109 and worked in tandem with the January 4 ECU. It is characterized by reliability and a long service life.

The principle of operation is not based on a change in direct voltage, but on a change in the frequency of the output signal of an alternating signal U. When the frequency is high, this indicates high air flow, low frequency indicates low air flow.

The main advantage of a frequency flow meter is stable data transmission to the ECU when the voltage in the circuit drops (poor contact, oxidation, etc.).

Let's imagine that the contacts in the connectors have oxidized. Then the output signal of 1.02V will decrease and, for example, 0.9V will come to the controller. This is not critical, but it will increase fuel consumption.

In the frequency sensor, voltage surges do not affect the operation of the ECU in any way. Oxidation of the contacts will not change the signal frequency in any way, which means 100% of the output data will reach the recipient, i.e. controller (ECU).

Methods for checking sensor functionality

How to check the flow meter yourself? There are several diagnostic options, we suggest you familiarize yourself with each of them (the author of the video is the Bezdelnik TV channel).

Checking the mass flow sensor on the go

Shutdown

First you need to try disconnecting the flow meter from the power supply. To do this, you need to start the engine and let it run for a while. Next, you will need to disconnect the plug from the flow meter - after this, the emergency mode of operation of the motor should be activated. In this case, the volume of required air flow will be calculated in accordance with the throttle position. If, after switching off, you notice that the engine began to work more correctly and at the same time it became more dynamic, then the mass air flow sensor definitely needs to be replaced.

Diagnostics using a multimeter

Diagnostics can be performed using a multimeter; for this we recommend that you read the operating instructions for the tester. The device must be configured in the DC voltage measurement mode; it is usually marked with the symbols DCV or V.

To ensure that connecting the device does not cause difficulties, you need to know exactly the pinout of the device:

black-red or pink contact is a connection to the control module;
green is ground (grounding, ground), connected to the body or battery;
gray-white contact - output voltage;
yellow - used to supply current to the input.

Diagnostics with a multimeter is performed as follows:

To begin with, the tester should be turned on and the voltage value set on it to 20 volts, and then the probes from the device are connected to the corresponding contacts on the plug.
To make the connection more convenient, you can use pins; you will need two of them. Each of them is installed in a hole with green and yellow contacts. Then you will need to connect the probes of the device to these pins.
The next step is to activate the ignition and measure the voltage. Read more about the test results below (the author of the video is the IZO channel)))LENTA).

Checking the air flow sensor.
mass air flow sensor VAZ 2110, 2112, 2114, 2115, Priora, Granta, Kalina On a working device, the voltage level will be around 1.01-1.04. If the readings are between 1.02 and 1.05 volts, this indicates that the device will need to be changed in the near future. If the readings obtained are higher, then the flow meter must be replaced because it is faulty.

It should be noted that during operation, the voltage parameter will only increase, since the resistor components of the device wear out, and the resistance value, accordingly, decreases. You can also accurately determine the voltage using the on-board computer, if it has the appropriate function. To search, go to the flowmeter voltage section and find the U value.

Visual inspection

Demonstration of a faulty mass air flow sensor on Kalina, Priora, Grant, VAZ 2110-2112, 2114-2115

Replacing the air flow sensor

To replace the sensor with your own hands, you need to prepare a shaped screwdriver and a “10” key.

The replacement procedure consists of the following steps:

First you need to turn off the ignition and open the hood.
Then you need to disconnect the negative terminal on the battery.
At the next stage, you need to loosen the clamp with which the corrugation is attached to the mass air flow sensor.
Next, remove the corrugation from the pipe.
Then you need to bend the comb and disconnect the sensor connector.

Disconnecting the sensor connector
Then, using a “10” key, you need to unscrew the sensor mounting bolts to the air filter housing. Now you can remove the mass air flow sensor. Installing the sensor yourself is carried out in the reverse order.

Thus, if the car stalls and has all the signs of a breakdown of the mass air flow sensor, then before you start repairing it, you should check the level of its signal, it should not be low, perform a full diagnosis of the car and repair all faulty components and parts.

Checking the serviceability of the mass air flow sensor with a multimeter

You can also check the air flow in the VAZ-2110 using a multimeter.
This method is well suited if the car has a Bosch sensor with numbers 0280218004, 0280218037, 0280218116. Each cable in the VAZ-2110 sensor device provides separate functions:

yellow – indicates the signal input to the installation;
gray-white – removes supply voltage from the mechanism;
green – determines the grounding output;
pink with black - approaches the main relay.

Note that the wire colors may change, but the pinouts remain the same. For a better understanding of the mass air flow sensor in the VAZ-2110, a diagram of the sensor is presented below.

Step-by-step instructions for checking the mass air flow sensor in a VAZ-2110 with a multimeter look like this:

Turn on the ignition, but do not start the engine.
Connect the multimeter with the red wire to the yellow, black to green, using a probe. This procedure allows you to determine the voltage that has arisen between the terminals.
What’s good about the probe is that it is inserted through rubber seals along the wires without violating the integrity of the insulating material. The use of needles is considered incorrect; the error in measurements may be large.
Next, take readings from the multimeter.

The output voltage of the new device varies from 0.996 to 1.01 Volts. During operation, the values may change, mostly increasing. A higher voltage indicator indicates a greater degree of wear on the mass air flow sensor:

from 1.01 to 1.02 – the sensor is fully operational;
from 1.02 to 1.03 – the condition is not bad;
from 1.04 to 1.04 - soon the air meter will have to be changed;
from 1.04 to 1.05 – the condition is critical, operation is possible if no negative symptoms are reported;
more than 1.05 – it’s time to replace the sensor on the VAZ-2110 immediately.

Operating principle

Modern Nivas use BOSCH sensors 0 258 006 537; NTK:629-W2:8965 and others. These are zirconium elements that react to the volumetric amount of oxygen in the exhaust and produce an output voltage in the range: 0.1–0.9 V (high O2 content - low O2 content).

The operation of the device is based on the principle of comparing the amount of oxygen in the exhaust gases and in atmospheric air sealed in the internal chamber of the lambda probe. It has 2 platinum electrodes separated by zirconium dioxide, which are surrounded by different oxygen environments. The device starts working only when heated to 300 °C and above. When heated, zirconium acquires the properties of an electrolyte and a potential difference arises between the electrodes.

Therefore, during ignition, until the engine warms up and the oxygen sensor starts working, the fuel supply to the injectors is adjusted according to a cycle programmed in the ECU controller.

Comparison of MAF Bosch 037 and 116.

VAZ owners often have a question: which mass air flow sensor should they install to replace the damaged one?

The answer is simple - you need to install it the same as it was from the factory.

However, often the mass air flow sensor has already been changed. It also happens that the MAF insert element is, for example, 116, and the sensor housing is from 037. Or vice versa.

The main algorithm for selecting a mass air flow sensor (except for classics). If your car was manufactured before 2004 and has an ECU with a 55-pin connector January 5.1, Bosch M154 or VS-5.1, you need a mass air flow sensor 037.

If your car is manufactured after 2004 and has an ECU with an 88-pin connector January 7.2, January 7.2+, Bosch M797(+) - you need a mass air flow sensor 116.

Question: is it possible to install the common and cheaper MAF 116 instead of the expensive and rare MAF 037?

Answer: in principle it is possible, but it is extremely undesirable. The sensors differ in calibration. For correct replacement, it is also necessary to change the calibration of the mass air flow sensor in the firmware of the control unit.

How necessary this is - decide for yourself by studying the differences in the MAF calibrations given below.

In a simplified form, the recalculation of the mass air flow sensor calibration is as follows:

This means that with the same actual air flow, the measured amount of air with a mass air flow sensor 116 will be 10 percent more than with a mass air flow sensor 037. Accordingly, the ECU will calculate a longer injection time for the injectors, which means a 10 percent higher fuel supply.

Theoretically, instead of the ideal mixture composition of 14.7, it will be 13.2. This is a fairly rich mixture. The maximum permissible mixture composition is in the region of 12.1-12.3 - with a richer mixture, gasoline stops burning completely due to lack of air.

Verdict: when replacing DMRV 037 with DMRV 116, the vehicle’s traction may improve along with an increase in fuel consumption. If the system has a working lambda probe, due to automatic regulation of the mixture composition, the consumption will not increase significantly. If the system does not have a lambda probe, it is possible to increase fuel consumption by up to 10 percent while improving traction. It is also not necessary, but it is possible that the smoothness of engine operation at idle may deteriorate until it stops.

Chevrolet Niva cooling fan does not turn on

The Chevrolet Niva SUV, which is popular in our country, is equipped with a high-quality cooling system that allows you to constantly maintain optimal engine thermal conditions. A special role in this unit belongs to two fans, which provide the required air flow through the radiator core.

If the cooling fan on a Chevrolet Niva does not turn on, excess heat will no longer be removed from the engine, which will lead to overheating of the engine. Since the number of cooling fans on this car model has been increased, the electrical circuit of their operation has become much more complex than in classic passenger cars.

If the cooling fan does not turn on on a Chevrolet Niva, the first thing you need to do is check the condition of the fuses responsible for the operation of the unit. The fuses are located in the mounting block under the front panel, near the front passenger's feet. This car has two fuses that protect the electrical circuit of the fan motor.

The mounting block contains three relays responsible for connecting the left fan at high speed and the right fan at low and high rotation speed. The additional relay is activated when a signal is applied from terminal number 46 of the ECM to terminal number 86. In this case, the voltage to the fan motor terminals passes through a resistor.

If there is no control signal, we can talk about a failed relay. At the same time, the cooling fan on the right side does not turn on on the Chevrolet Niva

It is important to remember that the same control signal is responsible for turning on the left fan. In this case, a jumper process occurs between terminals 85 and 86

However, the fan motor on the left is powered via a separate fuse.

Removing Chevrolet Niva cooling fans

The cooling fans on the Chevrolet Niva do not turn on even if the sensor that detects the coolant temperature breaks down. According to this sensor, the system understands how much the coolant temperature has increased or decreased. In this case, the controller determines whether to turn the fans on or off.

It happens that fans do not turn on due to deformation of the plastic casings of the parts. This can happen if the temperature in the engine compartment is too high. In this case, the fan blades will touch the casing, which will lead to overheating and melting of the tips. When the fans stop, the blades will simply weld to the casing and will not be able to work the next time they are turned on.

Replacing this part is relatively easy. The on-board computer registers errors such as P0340, PO342, PO343.

Mechanical specialists, even if the sensor is in good working order, still recommend changing it every 4-5 years - such prevention will protect you from breakdowns and accidents, especially since the part is very cheap despite its importance. After all, the semiconductors inside the sensor react poorly to temperature fluctuations - remember your school physics course

There is a special offer on our website. You can get a free consultation with our corporate lawyer by simply submitting your question in the form below.

On the Niva 2123, the idle speed control is made in the form of a small electric drive with a spring and a rod ending in the form of a needle, which are enclosed in one housing. The IAC is attached to the throttle body. The sensor starts working when the key is turned in the ignition switch. At this moment, the rod rests against a special hole to count the necessary steps, after which the valve returns to its original position.

Features of installation and operation.

The disgusting thing is that the Niva mass air flow sensor “dies” without a “check engine”. That is, his death can be confirmed by a “doctor” who knows what indications should be included in the diagnostic program. An indirect sign is sometimes “dullness” when accelerating.

Now about the designers. For me, the bible is the German and Italian literature on engines. It clearly states that the flow meter must be installed at a distance from the receiver or damper, no further than 2-3 cross-sectional diameters and not have 90-degree turns, otherwise there will be a very large error due to the inertia of the air flow and its heating in the engine compartment. Remember how the flow meters are located under the hood of the Niv and ShNiv......and smile sadly)))

Articles on the topic: air filters

The main signs of a malfunction of the mass air flow sensor are loss of engine power, difficult starting, “floating” engine speed. To find out the exact cause of the flow meter failure, you need to visually inspect the device and then test it with a scanner (via Openidag), a voltmeter or a motor tester.

Phase sensor - DF

It's also a camshaft sensor. The VAZ phase sensor is designed to determine the angular position of the camshaft. The main function is that when the engine is running, the phase sensor provides a pulse signal to the controller synchronizing fuel injection with the opening of the intake valves. Failure of the phase sensor switches the fuel supply to pairwise-parallel mode, which leads to a slight (up to 10%) increase in fuel consumption. And I’ll also add this “miracle of nature” is a headache and a source of a lot of errors, for example the famous 0301, 0302.... In my humble opinion, this is the same disgusting and abomination as the old-style hydraulic compensators. But what has grown has grown. (How to get rid of it forever, lambda, roll sensor - will be written in the article about chiptuning). The only normal manufacturer of this sensor is Avtovazagregat. The logo is visible in the photo.

Source

Possible sensor malfunctions

There may be several device malfunctions:

the sensor is clogged with dirt;
mechanical damage to the device;
lack of contact, that is, damage to the power supply wiring of the device.

The main symptoms of controller failure:

A Check indicator appeared on the control panel. As practice shows, this lamp most often lights up when the controller breaks down, so to determine the malfunction you need to connect to the electronic control unit. Engine power has decreased

Of course, this symptom is indirect, since a decrease in power can be caused by various malfunctions, but, nevertheless, it cannot be ignored. Fuel consumption has increased. This problem can also be attributed to the failure of the fuel pump or fuel filter, but the performance of the mass air flow sensor also needs to be checked. In addition, the acceleration dynamics of the car will be reduced

As a result of less air entering the combustion chambers, the quality of the air-fuel mixture as a whole will be lower. Accordingly, because of this, the car cannot accelerate normally. And if you press the gas, then when accelerating the VAZ 2112 may move jerkily. Poor engine starting; in more severe cases, the engine will not start at all. This, again, is due to a poor-quality combustible mixture. Such a mixture can cause detonation, which contributes to poor engine starting. In addition, uncharacteristic popping noises may be heard from the exhaust pipe. When the car is idling, the engine speed will fluctuate. This problem is due to the different volume of air flow that enters the combustible mixture (the author of the video is the channel In Sandro’s Garage).

How to check the air flow sensor (3 ways to check)

In some cases, to check the mass air flow sensor, it must be removed from the car. Dismantling procedure:

Loosen the clamp
Remove the air pipe,
Unscrew the screws securing the sensor to the air filter housing.
Before disconnecting the electrical connector, you must remove the negative terminal from the battery. This must be done so that the electronic engine control unit does not generate an error and the check lamp does not light up.

Method number 1. Visual control

To do this, you need to remove the sensor and carefully inspect it for mechanical damage or foreign objects or debris. It is also worth visually assessing the integrity of the heating filament sensors or heating film.

Such problems can arise due to a leaky air filter housing, or due to a poor-quality air filter.

If visible damage is detected, the sensor must be replaced. And if there is debris or dirt in it, the air flow sensor can be cleaned with special products or a carburetor cleaner (alcohol-based spray). Mass air flow sensors are very fragile, so be careful not to clean them mechanically. The sensor cannot be repaired!

Method number 2. Power off

The easiest way to check the mass air flow sensor is to disconnect power from it. With the engine not running, disconnect the electrical connector on the mass air flow sensor. Then we start the engine.

In this situation, the engine control unit switches to backup mode and replaces the readings of the disabled sensor with those programmed by the manufacturer.

In this case, engine operation should normalize and idle speed should increase. For additional checking, you can drive a car with the MAF connector disconnected - 100-200 meters. If all symptoms of a malfunction of the mass air flow sensor have disappeared, then the sensor is transmitting incorrect data - it is considered inoperative and requires replacement.

When checking the mass air flow sensor in this way, after disconnecting the electrical connector from the sensor, the “Check” engine error lamp will light up on the instrument panel.

After completing the check or replacing it, you will need to reset the error! To do this, you can disconnect the negative terminal of the battery for a few minutes (carefully, absolutely all settings will be lost). In some car models, the error can only be reset at a service center using a special scanner connected to the car’s diagnostic connector

Method number 3. Checking with a multimeter

To check the air flow sensor with a multimeter, you need to know which parameters to measure and from which contacts of the electrical connector. They may differ for each car brand. The location of the sensor wires and terminals can be found in the vehicle's electrical diagram.

For example, on Bosch sensors that are installed on VAZ and GAZ cars, you can check the voltage (V) between the incoming signal and ground at the mass air flow sensor connector. To do this you need:

Turn on the car ignition, but do not start the engine,
Connect the red (+) probe of the multimeter to the yellow wire,
The black (-) probe goes to the green wire of the connector.
We set the mode switch on the multimeter to measure the minimum direct current.

The voltage at the contacts should be in the range of 1.00-1.04 Volts. If the readings are higher, the sensor requires replacement.

Additionally, you can remove the sensor without disconnecting the electrical connector and apply a stream of air to the sensor from the air filter side. The voltage should increase to 1.3 Volts, in which case the air flow sensor is considered working.

Depending on the sensor design, it is still possible to measure the resistance on the resistors. Moreover, the measurement results at different air temperatures will be different. Accurate data on the optimal values of resistance readings, measurement temperatures and the location of contacts on the connector are usually indicated either in special technical literature or in the car repair instructions.

Replacing the sensor - instructions

Using a screwdriver, unscrew the clamp of the air intake corrugation at the sensor outlet, pull it off and carefully inspect the internal surfaces of the sensor itself and the corrugation. These surfaces must be dry and clean; traces of condensation and oil are unacceptable. If the air filter is changed rarely, then dirt getting on the sensitive element of the sensor is the most common cause of its breakdown in VAZ cars.

There may be oil in the mass air flow sensor as a result of an increased oil level in the engine crankcase, or the oil sump of the crankcase ventilation system is clogged.

Next, unscrew the 2 screws of the sensor with a 10mm wrench and remove it from the air filter housing. There should be a rubber sealing ring on its front part (at the entrance edge). It prevents unfiltered air from being sucked into the intake tract through the sensor.

If the ring is out of place and stuck somewhere in the air filter housing, then there will be a thin layer of dust on the inlet mesh of the sensor itself. This is the second reason that destroys the mass air flow sensor ahead of time.

Correct assembly should take place in the following sequence: put a sealing rubber band on the sensor, check the sealing skirt, then insert everything together into the filter housing.

This concludes the visual check of the mass air flow sensor at home. You can check its operation 100% only with the help of special equipment in a car service center. For example, using a technique for assessing the oscillogram when the throttle is sharply opened to the cutoff mode (a motor tester is needed), or assessing the oscillogram when the ignition is turned on.

On most foreign cars, a mass air flow sensor was installed until 2000; subsequent generations of models began to be equipped with a pressure controller. Replacing a non-working sensor is simple and can be done on your own without any problems, you just need to buy a mass air flow sensor that matches the ECU firmware version. Its price is around 3,000 rubles, depending on the manufacturer.

Overview and characteristics of the mass air flow sensor

The sensor is connected to the electrical harness and is located in the intake tract. The signal from the mass air flow sensor is a direct current, which has its own voltage. The magnitude of the current depends on the movement of air in the Priora that has passed through the sensor. The Priora mass air flow sensor includes:

a ring located inside the sensor, it is designed to fix the filter;
the filter itself, located in the mass air flow sensor;
inlet flange;
different thermoelements;
electronic board;
contact connector;
outlet flange.

3 thermocouples were installed inside the sensor. The first determines the temperature in the environment. Heating the air to the desired specific temperature is assigned to the next two thermoelements.

During the measurement of electrical power, the determination of the consumed air begins to occur. Electric power maintains the temperature at the desired level.

The filter that is installed in the Priora mass air flow sensor prevents large particles from entering the sensor housing. If this happens, the thermocouples may fail. It also has the function of cutting air to ensure even distribution of air. The filter is fixed with a ring intended for it in the inlet flange.

There is one rubber ring on each side of the housing for sealing. This is done to prevent air from being sucked in. Great importance should be paid to the seal ring located between the housing and the outlet flange located in the sensor.

If air begins to be sucked in, the system will not be able to take this into account, as a result of which the fuel mixture will become leaner. In this case, it is impossible to ensure maximum engine performance. It will be difficult to know that this is the problem with poor sensor performance. This will be difficult to do even with measuring instruments.

The mass air flow sensor on Priora is of the film type. The film is placed on a ceramic base. It contains both measuring and compensation resistors. These resistors are located inside the film. With this design, the sensor looks more reliable.

The film performs only the measuring elements. The substrate, in turn, functions as the strength elements of the structure. But such a sensor also has its drawbacks. Such sensors have a mechanical contact between the resistance track and the tire made of metal, resulting in wear.

DETAILS: Tips on how to reduce fuel consumption in a car - Financial Life

Signs of a malfunction of the mass air flow sensor on a VAZ-2110 and diagnostics

The automotive market does not stand still; manufacturers are constantly improving car engine power, fuel consumption, aerodynamic values, and coming up with options for changing overall comfort. The main and obvious improvement was the transition from the use of a carburetor method of power supply to a more efficient injection system.

How does the latter work? Regulates the quantitative supply of fuel according to a single dosage for the operation of the power plant in different formats of activity. This allows you to reduce the amount of air consumption and ensure maximum power output from the power structure.

However, mechanics argue that the design of the carburetor system is technologically simpler, because the carburetor operates mechanically, which means that the mechanism can be assumed to be highly reliable. The VAZ-2110 is equipped with such a system. The advantage of the device is that the fuel-air mass is formed in the carburetor and in the cylinders through vacuum, which is created by the pistons.

The technical version of the injection system is more complicated. The working mixture appears in cylindrical products, and the supply of its components is realized separately from each other.

The required amount of fuel is provided by the electronic control unit, but it needs to have several important characteristics:

how is the crankshaft positioned?
what is the rotation speed;
how much air enters the cylinders;
what volume is contained in the exhaust gas;
where is the throttle valve located.

These data and the calculation of the required fuel are responsible for the sensors recorded in the individual components of the power product - mass air flow sensor, which we will look at in more detail right now.

How to check the mass air flow sensor for serviceability

There are several basic methods for checking the mass air flow sensor, which allow you to verify its malfunction.

Checking the mass air flow sensor in motion

The easiest way to diagnose a flow meter is to analyze the operation of the engine when the sensor is forcibly turned off. The check proceeds as follows:

It is necessary to open the hood and disconnect the connector from the mass air flow sensor. After this, close the hood; Next, get behind the wheel of the car and start the engine. The car should start to operate in limp mode, in which the Check Engine light will be on.

In such a situation, the amount of air in the fuel mixture will be determined depending on the throttle position; Try driving the car and pay attention to its dynamics in comparison with how the car worked before the mass air flow sensor was turned off. With the sensor turned off, the car should become “more lively”, that is, accelerate faster. If this is the case, then we can confidently talk about problems with the mass air flow sensor.

If this is the case, then we can confidently talk about problems with the mass air flow sensor.

It is highly not recommended to operate a car for a long time with the mass air flow sensor turned off.

Checking the mass air flow sensor with a multimeter

You can diagnose a problem with the sensor using a multimeter. To do this, you must first understand the design of the device and its “pinout,” that is, the wiring of the wires on the board. There are 4 wires coming out of the mass air flow sensor. Depending on the MAF model and manufacturer, their colors may vary, but in most cases they are as follows:

Pink (or pink-black): wire to main relay;
Green: wire to ground;
Gray: wire to power;
Yellow: signal input.

To check the mass air flow sensor, the multimeter must be set to constant voltage measurement mode and set the limit to 2 Volts. Next, you need to turn on the ignition, but do not start the engine. Once this is done, connect the multimeter's red lead to the sensor's signal input (yellow wire) and the black lead to ground (green wire). This can be done without “exposing” the wires by inserting the probes of the diagnostic device through the rubber seal of the connector.

Based on the measurement results, conclusions can be drawn about the state of the sensor:

Fully serviceable device (new): 0.996 - 1.01 Volts;
The sensor is in good condition, but has already worked: 1.01 - 1.02 Volts;
The sensor has been working for a long time, but is still working: 1.02 - 1.03 Volts;
The mass air flow sensor will soon need to be replaced: 1-03 - 1.04 Volts;
The flow meter is close to failure, but continues to cope with the tasks: 1.04 - 1.05 Volts;
The sensor needs to be changed: 1.05 Volts and above.

Some modern on-board computers allow you to view the voltage on the mass air flow sensor. In such situations, you can do without a multimeter.

Visual inspection of the mass air flow sensor

Experienced motorists can determine a malfunction of the mass air flow sensor by its appearance. The first step is to remove the mass air flow sensor, and then inspect it carefully. Signs of a malfunction are liquid getting into the air pipe and the mass air flow sensor (or the presence of mechanical damage).

Most often, liquid may end up in the sensor for the following reasons:

Increased oil level in the crankcase. In such a situation, oil enters the sensor;
Clogged oil sump of the crankcase ventilation system;
Untimely replacement of the air filter, due to which dirt gets onto the MAF hot air anemometer.

The easiest and most reliable way to diagnose problems with the mass air flow sensor is to replace it with a working device. For example, you can remove a suitable working sensor from another car, install it and make sure that engine operation has stabilized. In such a situation, you can immediately go buy a new sensor without diagnosing it with a multimeter or other methods.

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Symptoms of a malfunction of the mass air flow sensor on a VAZ-2110

Now about the symptoms of a malfunction of the mass air flow sensor. You need to understand that you can definitely blame the mass air flow sensor only after accurate computer diagnostics of the engine management system. Even the on-board computer can easily make mistakes. However, we will try to identify the breakdown without involving specialists.

Symptoms of a sensor malfunction may coincide with symptoms of other malfunctions:

Increased or floating idle speed.
It is impossible to adjust the CO level at idle.
The engine stalls immediately after starting, the speed is maintained only when the throttle is open.
Increased fuel consumption.
The Check Engine light comes on.
Dips when changing speed, loss of power and dynamics.

Diagnostics of mass air flow sensor

In principle, the mass air flow sensor is not as critical for starting the engine as, for example, the DPKV. It can be turned off by pulling out the connector, the ECU will go into emergency mode and will determine portions of air in the fuel mixture using another sensor - the TPS throttle position.

Therefore, the breakdown is determined in several stages according to the degree of complexity:

visual inspection and disconnection of the sensor;
determining the compliance of a specific modification of the mass flow sensor with the ECU firmware;
diagnostics with a tester in voltmeter mode.

This will reduce the complexity of the process. For example, before checking the mass air flow sensor with a tester, you should make sure that the sensor is compatible with a specific MIKAS controller and that the original brains have not been flashed.

Checking the serviceability of the mass air flow sensor using a multimeterChecking the serviceability of the mass air flow sensor using a multimeter

Visual inspection

The mass air flow sensor is checked after access to this sensor is provided. To do this, you will need to partially dismantle the air intake elements (usually the corrugation). Knowing how a VU meter works, you can visually detect mechanical damage or traces of liquids/dirt in the pipe.

Rice. 11 Inspection of the air sensor and corrugation

Oil gets inside the corrugation due to a clogged oil sump of the crankcase ventilation system or when the lubricant level inside it increases. If the machine's maintenance schedule is violated, dust and dirt get onto the walls of the pipe, as the air filter becomes clogged.

After removing the sensor from the air filter housing, the inlet mesh should be clean. If there is a build-up of dust, most likely the rubber seal was not installed tightly and unfiltered air was getting inside. In any of these cases, the operation of the mass air flow sensor is disrupted by default.

Diagnostics on the move

The following method for checking the air sensor allows you to determine its performance. You don’t need a tester or other tools for this:

Diagnostics of the mass air flow sensor is carried out after disconnecting the ECU connector;
the engine starts, Check lights up on the panel, indicating a sensor malfunction;
however, the controller goes into emergency mode, ensuring the operation of the internal combustion engine;
If the dynamic characteristics of the engine improve when driving with the air sensor turned off, then the mass air flow sensor is faulty.

Rice. 12 Disabling the mass air flow sensor

Compliance of the mass flow sensor with the ECU firmware

As necessary, owners reflash the computer's brains to improve performance, while getting side problems. For example, if the MIKAS controller has been updated with firmware, the mass air flow sensor may not work correctly.

In this case, it is fundamentally incorrect to talk about a sensor malfunction, but its signals are not intended for the new version of the MIKAS controller that was installed on it. In this case, the only way to identify signs of a malfunction in the mass air flow sensor is:

change the angle of the throttle valve (usually a 1 mm shim near the throttle stop);
disconnect the mass air flow sensor while the engine is running (pull the chip out of the connector).

Design of the mass air flow sensor

Car enthusiasts call the mass air flow sensor a flow meter; in specialized literature it is designated as a volume meter. What is actually measured inside this electronic device is not the volume of air passing through it, but its mass per unit of time, moreover, compressed.

Since Ohm's law is familiar to every school graduate, the design of the mass air flow sensor is understandable to 100% of car enthusiasts:

the device is analogous to an anemometer that measures flow speed;
inside a tubular housing with an air deflector and a mesh metal screen at the inlet, the sensor itself is inserted perpendicular to the flow with a connector extending outward;
Apply a current of 500 - 1200 µA to the thread or film inside the sensor, remove the voltage value 0 - 1 V in reverse flow or 1 - 5 V in normal mode;
when current passes, the element heats up, its resistance increases (500 - 700 Ohms), and the voltage changes accordingly;
The air flow cools the wire, the resistance decreases, and the voltage increases.

Rice. 4 Design of filament air flow sensor

The mass air flow sensor is connected according to the diagram below:

green – to ground;
white-gray – output voltage;
yellow – input signal;
dark – output signal.

Rice. 5 DMRV connection diagram

The film MAF has a built-in platinum resistor on a ceramic plate. In a filament sensor, the resistance is made of an alloy of iridium and platinum. The first VAZ models were equipped with sensors that controlled the flow rate based on the frequency of the output signal. Currently, domestic and foreign cars have mass flow sensors that determine fuel consumption based on voltage.

Rice. 6 Film mass air flow sensor

To increase functionality, the operating sensor uses two temperature-dependent elements. Since the difference in air temperature can introduce an error into the device readings, the second thread element compensates for it by measuring the temperature of the environment. Common to all devices is the presence of an adjusting screw, which is used to adjust the CO with your own hands. The designs of different manufacturers differ in the following details:

thread thickness – 0.07 – 1 mm;
method of fastening the thermally dependent element - laser welding, hooking with a loop on an elastic suspension;
thread geometry – V-shaped or U-shaped;
The design of the stand is square, eliminating errors when rotating the element around its axis.

Rice. 7 German sensor and Russian analogue

In addition to these differences, factors to consider:

thread devices began to be produced by Bosch and General Motors, then interchangeable analogues appeared from the APZ and JSCB Impuls plants;
introduced a film-based air flow sensor from Siemens, which was copied by the Kaluga Research and Production Enterprise AVTEL;
the thread is heated to 140 - 170 degrees, the film to 100 degrees;
the accuracy of measuring film modifications is lower - 4%, for thread modifications is higher - 1%;
The devices are interchangeable with each other, but only together with a bundle of wires, since the pinout of the wires does not match.

Rice. 8 Sensor connector

Currently, thread sensors are discontinued in Europe for a number of reasons:

low level of manufacturability of thread production;
the presence of corrective lambda probes;
automatic calibration of films in blowing units.

In other words, manufacturers sacrificed speed and high accuracy for the sake of significantly reducing the cost of film mass air flow sensors.

There is a domestically produced mass air flow sensor M with protection against overvoltage, short circuit and conducted interference.

Rice. 9 Modification of mass air flow sensor M

By default, thread sensors are based on the principle of self-cleaning of a temperature-dependent element. After stopping the engine, the ECU independently supplies current to the filament to warm it up to 1000 degrees for 1 second. The adhering dirt burns out completely.

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.

Part diagnostics

Serviceability is determined with a multimeter in voltmeter mode. The results of the check are interpreted as follows:

The sensor is working: 1–1.02 V.
OK, cleaning required: 1.03 V.
average wear, readings are incorrect: 1.04 V.
high wear, urgent replacement needed: 1.05 V.
the part is faulty: 1.06 V. The engine operates in emergency mode, relying on the readings of the throttle assembly.

After cleaning, you need to check the flow meter again; the indicator should be at 1.02 V. If the mass air flow sensor breaks down, it cannot be repaired. If the flow meter fails, it will have to be replaced with a new part.

The vast majority of foreign cars with injection engines after 2000 began to be equipped not with mass air flow sensors, but with pressure controllers.

Video about checking with a multimeter

Signs of problems with the mass air flow sensor are identical on most brands of cars, be it a classic VAZ, Priora or Kalina, Chevrolet Niva or foreign cars.

How to properly clean the mass air flow sensor?

The cost of a new sensor sometimes reaches 4,000 rubles. When identifying its breakdowns, you cannot do without these expenses. But if the device gets dirty, you can clean it yourself. To do this, use special chemicals that are sold in car dealerships. For example, chemistry from Liqui Moly. A mixture of 30% distilled water and 70% isopropyl alcohol works well. To wash the part, it is not advisable to use carburetor cleaners, WD-40, dishwashing liquid or window cleaner. Cleaning is done like this:

Remove the device and its housing from the car;
Separate the sensor from the housing. You can use pliers to unscrew the fasteners;
Wash the resistors and channels of the part with chemicals. When using the product, you need to warm it up with a hair dryer to about 70 degrees.
Dry the device sensor;
Wash the body with soapy water, and then with water and dry it;
Assemble the element and install it in place.

In order to save money, some drivers try to restore the functionality of a broken mass air flow sensor by installing additional resistors, changing the ECU firmware, or blocking part of the air supply channel with aluminum. These methods may be dangerous or ineffective. Therefore, in the event of a breakdown, the part must be replaced.

Functionality of the mass air flow sensor

The normal ratio of the components of the fuel-air mixture is 14 to 1, where 14 is the share of air. Violation of the proportion is fraught with engine malfunctions, excessive fuel consumption and loss of engine power .

The functional purpose of the sensor is to measure the volume of intake air for the fuel-air mixture. Information from it goes to the ECU (electronic control unit) of the engine. In response, the control unit sends a signal to the injectors about the required amount of fuel. The flow meter is located between the air filter housing and the throttle valve, to which it is connected by wide corrugated pipes.

What is a DMRV?

Mass air flow sensor - sensor that measures mass air flow. The device is located in the engine air pipe between the air filter and the throttle valve. Thanks to it, the on-board computer determines the volume of air entering the cylinders necessary for complete combustion of fuel and normal operation of the car.

The device is equipped with a sensitive element consisting of 2 platinum threads with a diameter of 70 microns. One of them is cooled by passing air, and the other is a control. When the ignition is turned on, the wire heats up, sending a signal to the on-board computer to open the throttle valve and cool the element. At the same time, the injectors open, resulting in the formation of the required amount of fuel in a given engine operating mode.

After turning off the engine, the wire heats up to 1000 degrees. As a result, deposits, soot and dust particles on its surface that can affect the sensitivity of the sensor are completely burned.

There are outdated models of mass air flow sensors that operate using a vane damper, as well as more modern modifications with film-silicon elements and platinum coating.

Symptoms of a malfunctioning mass air flow sensor

Usually the sensor breaks due to natural burnout or contamination of the wire surface, which is caused by untimely replacement of the air filter and due to extreme driving. A sensor malfunction can be determined by a number of signs:

fuel consumption increased;
the engine is unstable at idle speed;
the engine does not start;
The “check” light is on on the on-board computer display.

These symptoms are indirect. Similar phenomena occur when the fuel pump is faulty, the throttle valve is stuck and the USR valve is bent. The exact cause of the breakdown can only be shown by diagnosing the meter using a motor tester, which allows you to construct and evaluate an oscillogram before the cutoff mode or when the ignition is turned on.

How to check the MAF sensor

Checking the mass air flow sensor is not particularly difficult and can be done in several ways:

In move

It is considered the simplest, but least effective way to diagnose a sensor. Disconnect the connector of the device, start the engine and drive the car, making sure that the engine speed does not fall below 1500. When the air flow meter is turned off, the controller begins to work in emergency mode, forming the fuel mixture according to the throttle position. If this way the car picks up speed faster than with the mass air flow sensor connected, it means the device has failed.

Multimeter

Before checking the mass air flow sensor with a multimeter, turn off the engine and turn the key in the ignition. Connect the red probe to the terminal of the yellow wire (located on the edge of the element, closer to the windshield), and the black probe to the green one (third from the edge).

The colors of the wires may vary, but the location remains the same. The voltage should vary in the range of 0.996...1.01 V, but if the numbers exceed the upper value, then the unit will require immediate replacement. Device readings of 1.05 V and above indicate a high output voltage and that the sensor is not working.

More detailed instructions for checking the DPRV with a multimeter are presented in the video

https://youtube.com/watch?v=EIyKzTBhyBA

Setting idle speed on a Chevrolet Niva

In this case, it must be carefully dismantled. But sometimes the device may be working properly, but problems in operation are associated with its clogging.

In this case, you can try to clean it with carburetor cleaner. Typically, this method helps to revive a device that has no visible mechanical damage. Checking the work. The idle speed of the Chevrolet Niva may be incorrectly adjusted if the sensor has increased travel between the valve and the supporting surface. When measured with a caliper, this distance should not exceed 23 millimeters.

Compliance with these parameters is necessary in order to ensure correct installation and not damage the throttle body. Before installation, the seat must be cleaned. You can also lubricate the O-ring with engine oil to make it easier to put it in place.

Operating principle of the idle speed sensor. The idle speed sensor, in other words, the IAC regulator, allows you to select the optimal crankshaft speed depending on the specified conditions.

If this part breaks down, the rhythm of the engine’s operation is disrupted, since a sufficient amount of air does not enter the combustion chamber, or a too lean mixture is formed, as a result of which the engine speed begins to float, this is especially noticeable at idle speed.

The principle of operation is as follows: Engine speed is read by the DPKV crankshaft sensor, and if this indicator is small, the IAC increases the air supply, simulating the gas pedal.

The system operates in the same way when starting from a cold state. The IAC increases the air supply so that the engine quickly warms up to the optimal temperature, or you can start driving without fear of stalling. Where is the idle speed sensor located on How to replace the idle speed sensor on a Niva Chevrolet Niva. On the Niva, the idle speed control is made in the form of a small electric drive with a spring and a rod with a needle-shaped end, which are enclosed in one housing.

The IAC is attached to the throttle body. The sensor starts working when the key is turned in the ignition switch. Do not purchase a regulator with a needle protrusion greater than 23 mm. Before installing the regulator, clean the valve seat, air duct and the surface for the regulator's O-ring in the throttle body.

We put the sealing ring on the cylindrical surface of the regulator. Apply engine oil to the O-ring.

We install the idle speed control in reverse. How to replace the idle speed sensor in a Chevrolet Niva. Thus, when the throttle valve is completely closed, the engine speed is maintained due to partial inflow through the additional bypass or bypass, from bypass - to move around the channel. The shut-off needle of the IAC valve, moving according to commands from the engine control unit, regulates the width of the valve gap and, accordingly, the flow of air into the engine, on which its speed depends.

Direct-acting speed controllers on the damper directly regulate the angle of maximum closing of the damper, leaving a small gap to maintain air flow into the intake manifold and, accordingly, ensure idle speed.

Video about IAC - what it is, principle of operation and design options: The control unit usually controls the number of revolutions based on the engine speed signal coming from the crankshaft sensor.

Most engine control systems are designed in such a way that when the accelerator pedal is pressed and the speed increases, the IAC drive is turned off and remains in its last state before acceleration. Thus, the load on the regulator drive is reduced. In diesel engines, to maintain idle speed, fuel supply control is also used by bypass type.

For this purpose, high-pressure fuel pumps use a special electronic control system.

Solenoid or rotary valves are used as IAC drives in high-pressure fuel pumps. This method makes it difficult to accurately set the idle speed. Therefore, the valves are controlled by a high-frequency pulse-width modulated signal (PWM modulation).