Regulator idle move or abbreviated IAC is a stepper motor equipped with a spring-loaded tapered needle. The principle of operation of this regulator is to control the operation of the engine at idle speed by changing the flow area of the additional channel that supplies air.
Such a feed is carried out bypassing the closed throttle, at the same time, the amount of air necessary for stable operation is supplied to the engine. This volume, in turn, is controlled by a mass air flow sensor or mass air flow sensor. Depending on the amount of air, this controller supplies the engine fuel mixture through the fuel injectors. Thanks to the position sensor crankshaft- abbreviated as DPKV, control and monitoring of engine speed is carried out, taking into account their number and in mandatory accordance with the mode in which the engine is running at one time or another - it controls the IAC, reducing or vice versa adding the amount of incoming air.
Warmed up to working temperature engine, the controller maintains a constant idle speed. When the engine is not warm enough, the controller is able to increase the speed with the help of the IAC and ensure that the engine is warmed up by increased revs crankshaft. In this operating mode of the engine, it is allowed to start driving vehicle without preheating the engine.
The idle speed regulator is an executive device, so it is not able to independently diagnose faults in its operation. If there is any problem, the IAC will not light up.
How to diagnose a malfunction of the IAC? Malfunctions of the idle speed regulator may be indicated by:
1. A spontaneous increase or decrease in engine speed in the common people is called - "speed float"
3. When starting a cold engine, complete or partial absence of increased speed.
5. By adding additional load in the form of headlights or a stove - there is a decrease idle speed.
Removing IAC
To dismantle the idle speed control, with the ignition off, disconnect its four-pin connector and unscrew the 2 mounting bolts. The installation of the IAC is carried out in the reverse order, but before that it is necessary to make sure that the distance between the end point of the taper needle and the flange is 23 mm. Be sure to also lubricate the O-ring on the flange with engine oil.
Signs of a malfunction of the idle speed regulator (IAC).
It 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 (throttle position sensor), and in this case, the "CHECK ENGINE" lamp clearly indicates a 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 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 cone 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 the 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.
Today, the hero of our story will be another imperceptible and modest component of the car system, which is called the idle speed control, or IAC. What is IAC, why do I need to adjust the idle speed, what are similar devices and what problems arise with them, we will talk about all this.
Every time you disengage and release the gas pedal, logically, the engine should stop, but it doesn't. Moreover, the motor continues to operate at certain speeds, independently supporting them. If you want to turn on the stove, any of the electrical equipment of the car at idle, then the engine speed will be automatically increased. And nobody touches the gas pedal. Therefore, air is supplied to the engine bypassing the throttle valve. It is for this feed that the IAC is responsible. And although this device is typical for engines with direct injection fuel, y carburetor systems there is a distant analogue. It is called solenoid valve... That's just this valve regulates the fuel supply through the idle channel. And the air supply at idle in carburetor cars adjustable by hand using special screws on the carburetor. And for this procedure you need optional equipment, and the necessary knowledge, of course.
What does IAC look like for Lada Kalina
In addition to maintaining the stability of the engine at idle, the IAC is responsible for the warm-up speed of the engine. So, if the engine is cold, then it idles for more high revs, due to which, it is carried out quick warm-up system, which means you can go faster. In addition, the idle speed control comes into action when you drop the accelerator pedal to apply the brake. It is thanks to the IAC that the engine does not stall in such situations.
Another one important function the idle speed regulator is that with its help the electronics prevents the engine from running on a lean mixture. Which is very harmful both for the engine itself and negatively affects fuel consumption. These are in general outline, idle speed regulator functions.
Types of idle speed controllers
In essence, the idle speed regulator is a valve that opens or closes the air supply to the system, through the so-called "bypass channel". The name comes from the English bypass - go bypass. In this case, air is supplied bypassing the throttle valve. Actually a variety of IAC, it is different ways opening and closing such a valve. The valve itself is a cone-shaped needle that enters the hole, blocking it, or, on the contrary, comes out of the hole, respectively, opening up air.
What the IAC looks like on a Chevrolet Lanos
V modern cars three types of idle speed controllers are mainly used:
- solenoid;
- stepping;
- rotary;
Solenoid IACs have a fairly simple device and principle of operation. When operating voltage is applied to the solenoid, its core is pulled in, thereby opening the air supply channel. When the solenoid is turned off, the core returns to its place, blocking the bypass channel. But such devices have only two positions - open and closed. Therefore, for fine adjustment of the air supply, they use a change in the frequency of supply of control pulses. Core with high speed moves back and forth, thus providing the right amount of air.
Rotary IACs use a rotor to open and close the valve. For fine adjustment of the air supply, a pulse-frequency type of control is also used here. Simply, instead of a solenoid, the valve drives a rotating rotor.
Well, the idle stepper regulator in its design has a ring magnet and four windings. It is on these windings that voltage is alternately supplied, due to which the control rotor rotates. Actually, the stepper motor has been known for a long time and is widely used in various techniques.
In principle, it is impossible to say unequivocally which type of IAC is better or worse. This is part of a complex and variable system, and therefore, it is the reliability and efficiency of the entire system that should be assessed, and not its individual element.
Video about problems with IAC
About breakdowns and problems with IAC
First, let's look at the signs that the idle speed controller is not working properly or does not work at all. In general, the symptomatology of violations here is similar to sensor breakdowns:
- throttle position;
- mass air flow;
- crankshaft position;
- camshaft position;
A rather expressive difference in the event of a breakdown of the IAC is the absence of a light signal - Check Engine... In general, the symptoms are quite common. Change in speed or even stop the engine at idle. Lack of engine response when turning on the stove, air conditioner, or other attachments, again at idle speed. Stopping the engine when releasing the gas pedal. If one or more of these symptoms appear, it makes sense to check the operation of the idle speed regulator. But remember, control of his work, in other words, Feedback is usually carried out using a crankshaft sensor or a camshaft sensor, which means that problems may arise in them.
Dirty IAC on Daewoo Matiz
The main reasons for the failure of the idle speed regulator should be considered problems with the wiring, the actual failure of the sensor itself - when the winding burns out or a mechanical failure occurs, as well as the reason for the failure of the IAC may be that it is corny clogged. Flush the idle speed regulator, usually with a carburetor washer, but the WD 40 will do. If you removed the IAC or even changed it, you need to calibrate the sensor. For this, as a rule, you need to de-energize the electronic unit engine control, install and connect the IAC, and then apply voltage to the ECU. After that, turn on the ignition for five to ten seconds, during this time, the electronics will calibrate the IAC.
Generally speaking, it is believed that the idle speed regulator should go through the entire engine life without problems, but the reality, as is usually the case, is far from ideal.
If the idle speed on the car starts to "float", and its operation as a whole has become unstable, then first of all, the idle speed sensor should be checked. In this article, we will tell you in detail about this, and also show you how to approach the issue of choosing this sensor.
Video with an overview of the main malfunctions of the idle sensor (+ replacement)
The main symptoms of a malfunction
Among all engine malfunctions, floating idle speed is especially noticeable, and they manifest themselves in the following:
- The engine stalls at the moment of gear shifting.
- Engine speed rises sharply, then drops to a minimum.
- The speed drops sharply at the moment of stopping with the engine running (at the moment of stopping at a traffic light - approx.).
If these symptoms are present, the idle speed sensor is usually defective. However, before you start repairing it, you need to understand how it looks and where it is located.
Location of the sensor on the engine
The idle speed sensor on the VAZ-2114 is usually fixed with two bolts next to the throttle assembly. It is easy to recognize by the presence of the power pad and its specific shape.
Idle sensor location
Now that we have figured out its location, we can proceed with diagnostics and, if necessary, repair.
Troubleshooting
The difficulty of diagnosing the idle sensor is that it will not show its malfunction on-board computer, and the operability can only be checked manually. What cannot be said about the throttle position sensor, because they have the same signs of malfunctions, and the most common on-board computer can identify the latter.
Sensor circuit check
Please note that on cars equipped with a 1.6-liter engine, it is necessary to dismantle the throttle assembly and remove it from the receiver itself by about a couple of centimeters.
We take a multimeter
If, after checking, it was found that the circuit is in good order, then you can proceed directly to the sensor.
Idling sensor check
When testing the sensor itself, you must connect the sensor to resistance test mode as follows:
If the test readings were abnormal, then you can try to clean it with a carburetor cleaner, or purchase a new one.
Which sensor should you choose?
In order to correctly approach the choice of the idle speed sensor on the VAZ-2114, you should know that the last two digits on the sensor article number have a special meaning. Because, if the article is old, it ends with " 01 ", And a replacement sensor will be supplied with the digits" 04 ", Then there will be no sense from this, because it simply will not work properly.
Native sensor and analog
Sensors from the number " 01 " on " 02 " and " 03 " on " 04 " respectively.
When choosing this device, pay attention also to counterfeit goods, because there are enough of them on the modern market.
The idle speed regulator (idle speed sensor, IAC) is a device for automatic stabilization and adjustment of idle speed. This idle speed sensor is often an electric motor that has a tapered needle.
The purpose of the IAC is to supply the amount of air necessary for stable engine operation bypassing the throttle valve at idle speed. In other words, if the engine is idling, the throttle is closed. In this case, air enters through an additional channel. The idle speed adjustment becomes possible due to the change in the cross-section of this channel, which overlaps the idle speed sensor needle.
The principle of operation of the idle speed sensor (IAC) is as follows. The amount of incoming air is determined by an air flow meter, after which the engine receives the corresponding signal and sends it through injection nozzles the right amount of fuel. The ECU also takes into account the readings (crankshaft position sensor), thus determining the engine speed in different operating modes. In parallel, the electronic control unit of the internal combustion engine controls the operation of the idle speed controller. After the engine reaches idle speed, the idle regulator IAC stroke under the control of the ECU, it opens an additional channel so that the required amount of air is supplied to the engine to maintain the specified idle engine speed.
IAC also changes idle speed depending on the degree of heating power unit... If the engine is not warmed up to operating temperatures, the ECU sends a signal to the IAC, the regulator increases the flow area of the additional channel. The amount of air increases, the control unit increases the fuel supply, thereby increasing the idle speed. At higher rpm, the engine warms up faster.
In a similar way, the ECU also compensates for changing loads on the engine in idle mode (turning on headlights, heating mirrors or seats, connecting climate control and other powerful consumers.) Thanks to the synchronous operation of the ECU and the IAC actuator, it is possible to dynamically increase or decrease the amount of incoming air that bypasses the throttle valve. As a result, the engine runs stably at idle speed.
Idle sensor malfunctions usually show up as the following symptoms:
- the engine will not start;
- the engine idles unstable;
- rpm float "cold" and / or "hot";
- there is an independent increase or decrease in idle speed on a warm engine;
- after entering idle mode, the engine stalls;
- when starting a cold engine, the speed does not increase to warm up;
- idle speed falls after turning on energy consumers (dimensions, headlights, air conditioning, heating, etc.);
The indicated malfunctions of the idle speed control can manifest themselves both individually and in combination. Note that "check" on dashboard usually off in case of problems with the IAC. Also, malfunctions of the idle speed sensor are reminiscent of the symptoms of a breakdown of the throttle position sensor (TPS). In this case, failures in the operation of the TPS are accompanied by the "check" lighting up.
To accurately determine the breakdown, it is necessary to check the idle speed regulator. After removing the IAC for diagnostics, cleaning or replacement and its subsequent installation, it is necessary to additionally calibrate the device. To do this, before installing the regulator, you will need to remove the terminal from. After installing the device, the terminal returns to its place, then for 10-15 seconds. the ignition is turned on without starting the engine. At this time, the ECU is calibrating the IAC. Please note that without removing the terminal from the battery, the electronic control unit will not calibrate the regulator. Then the engine should be started to check the operation of the idle speed controller with the engine running.
Read also
Setting idle speed on the carburetor and injection engine. Features of the XX carburetor adjustment, idle speed adjustment on the injector.
