This article will consider the IAC, what it is, the principle of operation, the main parameters. It will also tell you when you need to replace the regulator. idle move on VAZ cars. Do you know that modern car crammed with a variety of sensors and actuators. These include and It is supported with its help.If the IAC breaks down, the motor begins to function poorly, symptoms such as unstable rotation appear crankshaft, its turns are constantly jumping. In some cases, it is possible that the engine stalls and will not start.
What is an idle speed regulator?
To begin with, it is worth considering the external and internal appearance of the IAC. You will learn what it is from this article. It is installed not far from it, with its help, the crankshaft speed is maintained at a level of 700 to 900 rpm. This is done by adjusting the air supply to the throttle assembly. Externally, the idle speed regulator looks like a small plastic box, inside which there are small stepper motors(or solenoid). But some models are in the shape of a cylinder, made of metal. or a solenoid drives a metal stem that opens and closes the air supply.
Engine operation at XX
The operation of the engine at the most low revs- this is a very difficult regime for him. To begin with, fuel with air is very slowly fed into the combustion chamber, therefore, the formation of a mixture proceeds ineffectively. It should also be borne in mind that during intake manifold engine is very low pressure therefore it is possible for exhaust gases to flow back into the combustion chamber. Hence, we can conclude that there is a decrease in efficiency, an increase in exhaust toxicity, excessive wear of the elements of the cylinder-piston group. It should be noted that the price of the device is not very high. The idle speed regulator has a cost of about 400-500 rubles.
Idle speed regulation
If you remember carburetor motors, then the engine speed was not regulated using special screws. During the tuning process, it was necessary to control the oxygen content in the exhaust gases, the crankshaft speed. The procedure itself is very laborious and requires a qualified specialist to carry it out. When the first forced fuel injection systems appeared, the procedure was greatly simplified.
In fact, the IAC, what it is, discussed in the article, is an actuator, not a sensor. It is connected to an electronic control unit, which collects all data on the operation of the motor in real time. Based on the data received, the car's ECU monitors all the most important engine parameters internal combustion... It should be noted that the design of the idle speed controller is original, since in diesel engines a completely different adjustment scheme is used.
How does IAC work
So, above it was considered why an idle speed regulator is needed. Everything that has been described can be realized only if air is supplied at idle speed, bypassing throttle... This happens using a bypass channel. Depending on how open this channel is, the air flow changes. Please note that if the idle speed regulator malfunctions, the lamp " check engine»Does not light up in most cases. And remember, a regulator is not a sensor. IAC is because it does not measure anything.
When using a bypass IAC, the only drawback arises - it always tries to stabilize the crankshaft speed. True, while driving, the need for this practically disappears, since it is necessary to stabilize the speed only during gear shifting or braking.
What are the regulators
There are several types of idle speed controllers. Perhaps the simplest one is solenoid-based. When voltage is applied to it, the metal core is pulled out. Consequently, the bypass channel begins to close, reducing the air supply. And vice versa. But there is a small drawback. Regulators of this type have only two positions - open and closed. To make very fine adjustments, you need to apply voltage to the solenoid very often. Before checking the IAC, make sure that it is powered when the ignition is on.
The second type is a rotary regulator. The principle of operation is practically similar to the previous one. The only difference is the presence of a rotor that opens and closes the bypass channel. But the stepping idle speed controller, which consists of 4 windings and a ring-shaped magnet, has received widespread acceptance. Each of the windings is supplied with voltage from the electronic control unit. As a result, the rotor rotates, which opens or closes the bypass channel. These are the differences between different models IAC. What it is, you were able to learn.
The main breakdowns of the idle speed controller
If you are trying to diagnose the operation of the engine yourself, and you suspect that the idle speed controller is out of order, you should find out the main symptoms of a breakdown. And the very first is that the revs jump at idle speed. Also, during the gas release, the so-called stall occurs - the revolutions are held for some time at one value. It is also possible that the engine stalls during adventure speeds.
When powerful consumers are turned on, for example, headlights, air conditioning, acoustics, a decrease in engine speed is observed. It is possible that the engine may not start at all. It is worth noting that VAZ does not require any settings for the IAC. In case of failure, you will need complete replacement... The only exception to the rule is a blockage in the bypass duct. Therefore, before producing replacement of IAC, clean this channel.
If you say in simple words, then IAC (idle speed regulator) is a part that is responsible for regulating the idle speed of the car. Of course, this is an important part of any engine.
IN carburetor systems the sensor is called " solenoid valve"," Electropneumatic valve ". There are basic types of sensors.
- Solenoid- the principle of operation is based on electromagnetic force.
- Stepper- the principle is based on a ring magnet.
- Rotary- similar to the solenoid type, but it is the rotor that is used.
The sensor is a rather hopeful part and its failure is frankly a rarity. But any driver must understand that a breakdown can happen, and know how to properly check the performance of a part and make sure that the problem is in the IAC or another part of the engine. Before moving on to the symptoms of a malfunction and recommendations for repairing a part, it is worth discussing the principle of operation and its location inside the engine.
Location and principle of operation of the idle sensor
The idle speed regulator is located next to or on the throttle body. The location of the sensor may vary depending on the make of the vehicle. For example, on Opel and BMW models, the regulator is external, that is, it is located separately from the manifold.
In most cases, the IAC is secured with two bolts through a rubber O-ring and located directly in the throttle body. Difficulties in dismantling and installing the product may arise due to the sticking of the bolts, if such a problem is relevant, then try the simplest method - drilling.
The main task of the IAC is to supply fuel to idle which helps us save fuel consumption and maintain a stable idle speed.
When the ignition is turned on, the sensor rod moves forward to its maximum length and abuts against the hole on the throttle pipe.
After the required number of steps has passed, the valve returns to its original position. The number of steps is a constant value that is set by the manufacturer. When starting the engine, you can observe on the tachometer how the speed drops as the engine warms up, this is a process that occurs due to the presence of a sensor.
The more the stem is pushed forward, the more steps are used in the work. The average stroke is 250 steps. According to this principle, the engine receives the right amount of air for its full operation, and thus the idle speed of the car is regulated. With a cold engine, thanks to the regulator, the speed rises, which allows you to start driving without full warming up of the engine.
Further work is carried out and regulated by the mass fuel consumption sensor, it analyzes the air entering the engine and gives a command to supply fuel, based on the data obtained. By observing the engine speed, the controller begins to control the governor. Thus, the required air volume is monitored and further work is adjusted.
The main task of the IAC is a more complete combustion of fuel due to the supply of air and, of course, reduction of wear on the crankshaft bearings.
Idle sensor malfunction symptoms
The main problem will be that this detail is not equipped with any kind of self-diagnosis. On the control panel, you will not see a blinking light or an inscription that will indicate a malfunction of the IAC. Everything will depend on your attentiveness and how you feel and hear your car. Signs that indicate that a part is worth checking will be:
- the car began to stall at idle (irregular idle speed);
- a sharp drop or increase in revolutions during idle;
- when driving on a cold engine, the speed does not increase;
- when changing gear, the car stalls.
There are few reasons why the IAC failed. As they said earlier, this is a fairly reliable part, but it can still fail. There may be several reasons for the malfunction:
- Worn pilot adjuster needle.
- Broken contacts inside the part.
- Clogged needle due to poor quality fuel.
As we all know, fuel is one of the most important components of both the engine and the car as a whole, and the idle sensor is no exception. Most of the reasons for part breakdown are the use of gasoline with impurities.
Any changes in the operation of the engine speed indicate a malfunction and defective operation of the XX sensor. If the part fails completely, you will not be able to start the car without using the gas pedal. And such a procedure will negatively affect work. vehicle generally. Manufacturers do not recommend this practice for a reason.
Idling sensor check
Diagnosing a part is easy enough, but pay attention to a few points. The first problem may be the removal of the part, most manufacturers attach the XX sensor to screws, and in extreme cases they can be drilled out, but in some variations the part is installed on varnish. If your regulator is secured with varnish, be careful not to pull it off forcefully, as this could damage the intake side of the vehicle. In your case, it will be correct to dismantle the throttle assembly completely and only then disconnect the IAC.
The easiest way to check is of course visual inspection. On visual inspection, the first thing to look out for is contamination of the needle. Also pay attention to the condition of the contacts and the throttle valve itself.
If broken wires are found, they must be returned to their place. Solder them and, in order to avoid corrosion, treat with varnish.
It will be appropriate, if possible, to check the IAC with a multimer or homemade tester. You can check the resistance with a multimeter, and with a homemade tester (you can do it from charging mobile phone) check the stroke of the regulator.
If you find that the motor is destroyed, the stem is completely worn out, or the taper needle is worn out, the part will need to be replaced. Do not be too upset about this, the cost of the part will be only about 1000 rubles.
Idle sensor cleaning process
A cleaning process is required to stabilize operation, especially if during inspection you find a clogged needle or throttle valve. To clean the contacts, use a cotton pad: after dipping it in alcohol, wipe them off.
Clean the tapered needle with a carburetor cleaner or WD - 40. After sprinkling liberally on the needle, let it dry, then you can put the part back.
Cleaning the throttle body will take a little longer, but it won't be time consuming either. You will need any kind of cleaning agent: gasoline, thinner, carburetor cleaner, WD - 40. Also use a rag and a brush. Be sure to remove the flute before cleaning. air filter, and don't forget to clean the shutter on both sides.
Good day, dear readers, in this article we will analyze many reasons but mostly symptoms of malfunction of vehicle sensors. Remember that before you go to a hundred and panic, you should spend a little time and try to find the cause of the malfunction yourself and save money.
Signs of a malfunction of the TPS sensor:
- idling possible high revs, this is the most characteristic feature;
- a noticeable decrease in engine power and deterioration in throttle response;
- when the accelerator is pressed, jerks, dips and twitches;
- floating idle speed;
- when shifting gears, the engine turns off spontaneously;
- overheating is possible;
- detonation.
(personally, my symptoms were high revs, the inability to brake with the engine, jerks, a decrease in power and, accordingly, increased gas mileage).
The photo shows heavily worn tracks
The reasons for the malfunction of the TPS sensor may be:
- oxidation of contacts - you can help in this case, you need to take special liquid WD and a cotton swab to clean all contacts in the block and under the lid;
- worn-out sensor substrates if a resistive layer deposition was provided for in their design;
- the movable contact fails - some tip of this contact may break, then a scuff is formed and other tips also fail;
- the throttle valve does not close completely at idle speed - in this case, you can file it off a little seats sensor and the flap should close.
The tpdz sensor rarely fails, however, an ordinary car owner will not be able to diagnose its failure, and some also do not know where the sensor is. The sensor is located opposite the throttle valve.
Idle valve malfunction symptoms:
- unstable engine idle speed;
- spontaneous increase or decrease in engine speed;
- stopping the engine when turning off the transmission;
- absence increased speed when starting a cold engine;
- decrease in engine idle speed when the load is switched on (headlights, stove, etc.).
The idle valve in this state will not be able to function normally. The check error does not always pop up.
The best prevention of the idle valve is to periodically remove and clean the idle valve, usually in the fall and spring. The valve is located near the throttle valve.
Signs of malfunction of the DMRV sensor:
Signs of malfunction of the dmrv sensor or absolute pressure in the intake are characterized by:
- Up to 70 degrees, the machine works more or less well, after 70, an unstable idle speed begins;
- Dips during acceleration and undertraining;
- The car sometimes stalls at idle when hard pressing gas pedals;
- Increased consumption;
— Bad smell exhaust;
- Pops in the muffler during operation and sometimes pops in the intake manifold. (incorrect ignition timing due to faulty sensor)
The air flow sensor is very sensitive and it is not recommended to clean it yourself, the more often you change the filter, the longer it will serve you. The check error pops up only when the dmrv sensor has stopped working completely, and it can give incorrect readings for a long time.
You can check the dmrv or the mass air flow sensor with a multimeter or a diagnostic scanner at hand.
Signs of a malfunctioning speed sensor:
- the speedometer does not work or gives incorrect readings;
- unstable idle;
- increased fuel consumption;
- the motor stops developing full power.
- the arrow of the fuel gauge reacts almost instantly to fluctuations in the fuel level in the tank, because the computer thinks that the car is not moving, and less "smooths" the sensor readings;
- odometer does not reel mileage;
sensor in automatic transmission
- the automatic transmission, when shifting the speed, is reset itself to neutral, or it switches spontaneously illogically;
- the car stops responding to the gas pedal and starts coasting;
- in city traffic when gaining speed, the gearbox sharply increases the revs and does not accelerate, does not react to other modes 2 and 1. It seems to go only at 1 speed but does not brake the engine.
The principle of operation of the speed sensor on all cars is the same and it is quite possible to restore it yourself, let's take an example. The speed sensor is located, in most cases, on the side of the automatic transmission.
Signs and causes of a malfunction of the knock sensor:
- Comes into a disrepair quite rarely. Than the sensor breaks down, more likely something will happen to its wiring. Perhaps something happened to them if, at speeds exceeding 3000, the engine's sensitivity to how high-quality fuel is poured into it increases. If the fuel turns out to be of poor quality, there will be a “knock of fingers”.
- symptoms of incorrect ignition timing. Who drove cars with mechanical system engine management, he knows what I'm talking about. One has only to shift the UOZ by a few degrees to the early or late side, so the engine will either lose momentum, as if you are driving on the handbrake, or will start to detonate - ringing at a low load or exhaust system... Everything depends on the detonation resistance of the poured fuel and the UOZ at which your engine is running.
For example (from experience), I met Audi with V-shaped engine with two knock sensors, which flatly refused to develop full power. The engine was gaining momentum very sluggishly, and Pavlodar experts pointed out a clogged fuel system. However, when checked on the bench, the nozzles sprayed the fuel perfectly, and the pressure gauge showed the reference value of the pressure in the rail. But still, when measuring with a stroboscope UOZ, it turned out that it was displaced by more than 10 degrees from the normal value, which is described in the manual. The reason for this was one of the two knock sensors on the second engine block.
Another interesting case related to a malfunction of the knock sensor was with Subaru engine... At the time of purchase, the car, like the Audi described above, did not develop full power. At the same time, the engine ran very smoothly, fuel system(injectors, gas tank) was absolutely clean and there were no signs of any malfunctions at all. However, the owner of the car complained that he could not overtake the usual injection top ten. From experience with Audi, we tested the knock sensor on this engine, but the sensor turned out to be very “alive”. Resistances 540 kOhm, as it should be according to the specification. DD reacted vividly to tapping - 30-40 mVolts.
The reason was not found soon. On several American sites, I found owners of exactly the same cars who also complained about the terrible dynamics of the engine. But smart Americans quickly realized what was going on and shunted the knock sensor circuit with a capacitor, and there were those who did not want to mess around with electronics and preferred a lining made of a piece of rubber, which was placed under the sensor. As a result, the sensitivity of the DD decreased and the appearance of small vibrations in the motor was completely ignored. Thus, after a few kilometers, the car became frisky and dynamic.
The check error does not always pop up.
Signs of a malfunction of the coolant temperature sensor:
— Electronic system control sets the engine temperature suitable for starting to zero degrees Celsius and a corresponding command is sent to the auxiliary air regulator. In the event of a malfunction of the temperature sensor, the proportions of air and gasoline in the mixture will be far from optimal, which will make it difficult to start the engine in conditions low temperatures... After the engine can still be started, after two minutes, the electronic unit the control will decide that the coolant temperature has risen to 80 degrees. For this reason, you will have to play the gas pedal not only when starting, but also when the engine is warming up.
With the same malfunction, there will be problems in hot weather. When the engine heats up to a temperature close to the maximum allowable temperature, the control unit will assume that the antifreeze temperature is normal and will not take measures to correct the ignition timing. Power loss will occur and engine detonation will occur.
- idle speed is below normal.
- incorrect operation of the car fans, turn on on cold engine and do not turn on when required, as a result of which the temperature rises.
- the appearance of dark smoke from the exhaust pipe.
Most cars have 2 coolant temperature sensors, the data from the first goes to the dashboard, and the on and off of the radiator fan depends on the data of the second sensor.
The error does not always pop up.
Camshaft position sensor malfunction symptoms:
- the gearbox is locked in one gear, usually in the first, restarting the engine can solve the problem;
- the car moves in jerks;
- the vehicle experiences a difficult acceleration after 60 km / h.
- the engine periodically stalls, especially often at idle;
- pops in the system are possible exhaust gases;
- the spark disappears, it will not work to start the engine.
Crankshaft Position Sensor Malfunction Symptoms:
- detonation appears during intensive acceleration;
- unstable idle speed;
- the speed of the car rises or falls on its own;
- the engine cannot be started.
Signs of a malfunctioning ignition coil:
- It breaks down quite often. Symptoms are power sags that occur, a decrease in overall engine power, instability at idle, dips during acceleration, and even two-cylinder shutdown. If the distance to the service station is several kilometers, and it is possible to reach it, then turn off the corresponding nozzles. Otherwise, the gasoline injected by the injectors into the non-working cylinders, and the oil will be washed off from the disabled cylinders, after which it will flow into the crankcase.
You can check by turning off the ignition coils in turn, and when you come across a faulty coil, the engine will not change.
Symptoms of a generator malfunction:
- When the engine is running, flashes (or is continuously lit) control lamp battery discharge;
- Discharge or recharge (boil off) battery;
- Low light car headlights rattling or quiet sound signal with the engine running;
- A significant change in the brightness of the headlights with an increase in the number of revolutions. This can be permissible when increasing the speed (overgassing) from idle, but the headlights, having lit up brightly, should not increase their brightness further, remaining at the same intensity;
— Extraneous sounds(howl, squeak) coming from the generator.
Idle speed regulator article - principles of operation, possible malfunctions and their warning. At the end of the article - a video about checking the device.
The content of the article:
Engine idle speed, idle speed is the operation of a car without any load, when the engine is disconnected from the crankshaft and the wheels. Stabilization of the engine idling occurs due to the operation of the idle speed regulator, which is located in the throttle body.
For uniform operation of the engine, a strict dosage of the fuel mixture is required: air and fuel must be evenly mixed in certain quantities. At low revs, the sensor or idle speed regulator supplies air to the fuel bypassing the throttle valve, which starts working only when the accelerator pedal is depressed. Stabilization occurs by changing the flow area in the air line through which air enters.
A breakdown or any malfunction of the regulator affects the operation of the engine as a whole. The motor cannot reach the required number of revolutions of 800-1000 units (average value for passenger cars sedan class), there are power drops, interruptions in the supply of the fuel mixture.
After the car is started, the engine warms up the system, the speed is always slightly increased, after a while (10-40 seconds) the speed decreases to the idle speed.
- The sensor allows the power unit to gain the required number of revolutions after the start of the robots and reduce them to the idle speed setting parameter.
- The regulator maintains the required engine speed when the gears are switched, neutral speed is turned on, when stopping at traffic lights.
- The idle control adjusts the RPM to allow the engine to warm up quickly before driving. The increase in incoming air depends on the signal from the ECU, which corrects the operation based on the readings of the crankshaft sensor.
The main point that is important to know is that the signs of failure of the idle speed sensor are similar to those that are characteristic of a broken or seized throttle valve. Since the two nodes are located side by side, their diagnosis is carried out simultaneously.
The most common symptoms are:
- Engine speed is unstable. Differences in revs are clearly audible.
- The motor stalls at a traffic light when the transmission is turned off.
- Vibration of the engine at idle appears, which is noticeable on the body.
- The car does not move when the accelerator pedal is depressed.
- By connecting additional electrical components - air conditioning, headlights, etc. - the speed is noticeably reduced.
The regulator is located in the throttle body and is usually fastened with two screws. If the installation involves the reamed top of the bolt, then a complete dismantling of the damper will be required to clean the regulator. The main components of the sensor:
- regulator body;
- valve;
- ball bearing;
- spring;
- rotor;
- screw;
- stator winding;
- plug.
The solenoid type regulator operates on electromagnetic force. When voltage is applied to the coil, the core is retracted, the damper rises, opening access to the air flow. When the solenoid is turned off, the flap is closed.
The design of the stepper regulator includes a ring magnet and four types of windings. Voltage is applied alternately to each winding, a magnetic field arises, in which the rotor connected to the damper begins to rotate, the mechanism opens and closes.
Rotary encoders have a similar principle of operation with a solenoid; a rotor is used as the supply force.
The idle speed regulator cannot be repaired if the needle is worn out. It is required to replace the part. But if the stem channel is clogged, when it is jammed, the unit can be cleaned. If the electrical circuit is broken, you can diagnose the problem using a multimeter. Replacing the sensor does not take much time and even a non-professional driver can do it.
Regulator cleaning steps:
- Removing the assembly from the throttle body. First of all, the terminals are removed from the battery. The four-pin connector of the regulator is disconnected. The bolts are unscrewed.
- Analysis of the part.
- Soak the stem body in one of the solutions: alcohol, VD-40, carburetor cleaner, solvent, for 15 minutes.
- Do not rub. Blow out the part with a fan or hair dryer.
- Installation is carried out in reverse order... The distance between the flange and the sensor does not exceed 2-3 mm. Connects the connector.
It is easier to prevent a disease than to cure - this rule is known to all car owners, convinced from personal experience that simple prevention of components and assemblies is always more profitable than expensive repairs.
So that the regulator does not have to be cleaned and changed several times a year, it is recommended to follow these simple tips:
- Timely replacement air filters prevents clogging of the regulator stem channel.
- Moisture and dirt should not accumulate in the throttle valve.
- If the car is in cold weather for a long time without operation, the engine should be warmed up once every 24 hours.
Video on how to check the idle speed controller:
Signs of a malfunction of the idle speed regulator (IAC).
Idle speed regulator is an executive device and its self-diagnosis is most often not provided in the system. Therefore, in case of malfunctions of the idle speed controller, the lamp "CHECK ENGINE"does not light up on all vehicles. Symptoms IAC faults are in many ways similar to faults of the TPS (throttle position sensor), and in this case, the "CHECK ENGINE" lamp clearly indicates a TPS malfunction.
To malfunctions of the idle speed controllerthe following symptoms can be attributed:
Unstable engine idle speed,
Spontaneous increase or decrease in engine speed,
Stopping the engine when disengaging the transmission,
Lack of increased speed when starting a cold engine,
Decrease in engine idle speed when the load is turned on (headlights, stove, etc.).
Cleaning the idle speed regulator (IAC).
If the sensor does not work, then you can try to rinse and clean the sensor. Cleaning the IAC is an easy and quick process. For this we need a carburetor cleaner or wd-40.
1) First, we disconnect the wiring block from the sensor.
2) Apply a cleaner to a cotton swab and clean the contacts.
3) Take a small one Phillips screwdriver and unscrew the 2 sensor mounts.
(If there are no fasteners, then the sensor is planted on the varnish, in this case, you need to remove the entire throttle assembly)
4) We take out the sensor and look at its condition:
If the sensor is in oil and in black dirt, then it follows that in addition to cleaning the sensor, the entire throttle valve must be cleaned (How to clean and flush the throttle valve? ).
5) We take VD-40 or a carburetor cleaner and spray abundantly on the tapered needle with a spring, thereby clearing it of dirt. Then we dry the sensor and install it back. Check the distance from the probe body to the needle (23mm) before installation.
If there are no changes in the operation of the engine and the sensor at idle, then the guides of the tapered needle are worn out (replacement with a new sensor) or the wire inside the sensor is broken.
Checking the idle speed regulator (IAC).
Switch off ignition. Disconnect the harness connector from the regulator. Use a multimeter to check the resistance of the IAC windings. Resistance between system contacts idle speed adjustment A and B, and C and D should be 40-80 ohms... If not, replace the IAC. If yes Check resistance between terminals B
and C, A and D. The meter should show infinity (open circuit). If not, replace IAC. If yes, the IAC circuit is OK.| IAC schemes |
2) Disconnect the 4-pin IAC connector.
3) Unscrew the two fixing screws.
Installation of the idle speed regulator (IAC) is carried out in the reverse order, but after checking the distance from the flange to the end point of the taper needle, which should be 23 mm ... In addition, the O-ring on the flange should be lubricated with engine oil.
