Many people underestimate the importance of sensors or idle air control. But in fact, the speed stability depends on the correct operation of the IAC. It also prevents the car from stalling when the gearshift lever is in an intermediate position.
In this material we will talk about the meaning, device, and signs of malfunction of this device. We’ll also tell you how you can easily replace the IAC with your own hands.
Appearance of the device
Causes of malfunction
Floating engine speed shown on the dashboard
It’s not just that the speed in a car starts to fluctuate; this is due to the operation of many systems. Before we begin to consider the reasons, it is worth noting that with such an effect the check may light up or not, but as practice shows, the outcome of the reasons is the same.
Let's consider the main problems of the occurrence of floating speed at idle according to the practice of car enthusiasts and service manuals:
Method for eliminating floating speed on a 16-valve VAZ-2112
Before we move on to eliminating the causes, it is worth noting that untimely repairs can lead to the engine reaching the “start-stop” effect. This means that the engine will start and immediately stall at idle . Therefore, at the slightest occurrence of floating speed, it is worth eliminating the problem. So, let's move on to the actual repair.
Fuel system and everything connected with it
The effect of floating idle speed can occur due to intermittent injection. On older carburetor cars this happens quite often, especially during and after winter. So, to eliminate the causes on the VAZ-2112, it is necessary to perform the following operations:
- Check the operation of the gasoline pump , repair or replace if necessary.
- Replace the fuel filter, which may be clogged due to poor quality fuel.
- Check and clean injection nozzles. If necessary, replace faulty injectors.
- Check the fuel rail for leaks .
- Carry out diagnostics of injector wiring .
If the cause is found, then you should check whether the effect of floating speed has disappeared; if not, then examine the remaining systems.
General view and diagram of the fuel system
Ignition
The car's ignition plays a very important role in setting the speed. It is worth noting that a malfunction of spark plugs (incorrectly selected gap), high-voltage wires or lock can affect the achievement of this effect. Therefore, it is necessary to diagnose these particular components and parts, and, if necessary, replace them.
Replacing the ignition switch can eliminate floating speed
Bad gasoline
Now, the market for fuels and lubricants is quite actively saturated with counterfeits, and therefore even at trusted gas stations you can fill up with low-quality or “bodied” gasoline. This is one of the reasons for floating idle speed . To eliminate the problem, it is necessary to clean the entire fuel system. To do this, do the following operations:
- Remove and then clean the fuel tank.
- Replace the fuel filter.
- Remove the fuel rail and clean the injectors using a special stand.
- Blow out the fuel lines.
- Remove the fuel pump and clean (replace) the coarse strainer.
- Check the condition of the engine cylinders (this is not necessary, but recommended).
Poor quality fuel is one of the reasons for floating speed
Idle speed sensor
Like any engine and electrical part, the idle speed sensor has its own resource and service life, and therefore can fail. It is necessary to unscrew it, carry out diagnostics and, if necessary, replace it with a new one.
The idle speed sensor may be the main cause of floating speed
Throttle
A clogged throttle valve often caused the car to experience the effect that the speed began to float. Therefore, it is necessary to diagnose the condition of this element, and if necessary, clean it.
Throttle valve before and after cleaning
ECU errors
The accumulation of errors in the electronic control unit can lead to various incorrect commands. One of them may be idle speed. So, to fix the problem, you need to connect to the car using a special cable and reset all accumulated errors in the ECU.
Possible ECU error codes
Sensors affecting engine operation (possible malfunctions)
Of course, if a computer gives inadequate commands, this does not mean that it is broken. The reason may be the sensors involved in the system:
- IAC, regulating idle speed;
- Mass air flow sensor that monitors air flow;
- EGR.
Failure of one of these devices may result in floating speed. When the sensors have been checked and their operation is satisfactory, it is necessary to check the spark plugs and inspect the air filter. Sometimes the reason for the appearance of floating speed is the wiring of the sensor, oxidation of the contacts.
- IAC check.
Among all the works, this sensor is checked very first. It is attached to the throttle body next to the sensor that controls the throttle valve. The fastening consists of two screws. To check the functionality of the sensor, you must have a multimeter. The ignition is turned off and the chip with the wire is removed.
A multimeter measures the amount of resistance that exists between the sensor contacts. When everything is normal, the resistance will show 50 ohms. If the readings do not correspond to the standard, we can conclude that the regulator is broken. It cannot be repaired; a new sensor must be installed instead.
- DMRV.
This sensor, responsible for uniform air supply, is located on the body of the air filter. It shows how much air the engine sucks in in one hour. The measurement is in kg. I must say that the device is very reliable. Its main enemy is moisture, which can be absorbed together with air. As a result, the sensor malfunctions. It begins to show low speed values that are overestimated by about 15%.
As a result, the engine begins to idle unsteadily when the car stops after high-speed driving. After this, the vehicle is difficult to start. Fuel consumption increases. At idle, the air flow should be 8-10 kg/hour. When the rpm reaches 3000, the air flow should be in the range of 28-32 kg/hour.
To check the mass air flow sensor, you need a multimeter. In this case, it is necessary to measure the value between the two sensor connectors. The green wire goes to one, the yellow wire goes to the other. When checking, the engine must be turned off and the ignition on. The multimeter readings should correspond to the range of 0.999-1.02 V. With other values different from normal, we can talk about a breakdown of the mass air flow sensor.
- EGR.
This sensor is responsible for recirculating all exhaust gases. The valve sends a small amount of such gases into the combustion chamber of the engine. This promotes complete combustion of gasoline. Therefore, a minimum of toxic substances enter the atmosphere. The design of this valve is quite simple. But it often causes a variety of problems.
If you do not regularly clean the valve seat and take care of its seat, the engine will begin to operate intermittently. This is precisely one of the main reasons for the appearance of floating revolutions.
The situation can be corrected by cleaning the contaminated area with a special aerosol. You need to be very careful while cleaning. The valve diaphragm must remain dry and must not be touched by any foreign substances. It is important to prevent the substance from getting on the valve diaphragm.
To check the ignition module, it is necessary to install a working part in its place. If the engine starts to operate stably and no floating phenomena are detected, then the module has failed. It needs to be replaced.
A few words about carburetor engines. Typically, the cause of floating speed on cars of this type is poor adjustment or malfunction of the carburetor. In addition, poor air intake and failure of the XX valve also causes unstable engine operation.
The condition of the air filter also affects normal operation. However, in most cases, the cause of engine instability is the carburetor itself. To adjust, you need to rotate the quality screw and the fuel supply screw until the engine starts to operate normally.
Why does the VAZ-2110 idle speed fluctuate, and what to do?
When the idle speed fluctuates noticeably, or not very much, then, as a rule, this indicates a malfunction of the car. The problem is that the sign mentioned is not a characteristic symptom. Simply put, there are quite a few reasons why the idle speed starts to float. It is impossible to find out what exactly failed by eye - a comprehensive diagnosis will be required. It's not the easiest way to try to figure out the situation on your own, but you can save a lot of money and get to know your car better. We'll tell you how to do everything right below.
Device role
On injection engines that are installed on the VAZ 2110, the XX regulator serves to control the stable operation of the power unit. It is unlikely that you will be pleasantly surprised by a situation in which the idle speed starts to fluctuate, and every now and then the car will stall.
Some people do not know about another very important role of the idle speed sensor - warming up the power unit in case of low air temperature.
It is generally accepted that if there is an injector, there is no need to warm up the engine. The opinion is wrong. Do not overstress the engine, but first let it run for a while without increased speed. This will have a positive effect on the reliability and service life of the motor. .
Location
Externally, the IAC looks quite simple. It looks like a small electric motor. Its design includes three parts:
- Stepper motor;
- Spring;
- A rod with a needle at the end.
And the desired regulator is located near the mechanism that is responsible for changing the position of the throttle valve. There is no complex fastening system. To dismantle you just need to remove the mounting bolts.
How does he work
The function of the IAC is to regulate the amount of fuel supplied. He may indicate the need to increase or decrease the quantity. An important nuance is that the sensor performs its functions directly when the idle speed is turned on.
The actual action of increasing or decreasing occurs due to the extension or retraction of the needle at the end of the rod. The needle is responsible for closing or opening the special channel to the required extent.
Learning to distinguish a fake from an original
Today, many people complain about the abundance of counterfeit products on the auto parts market.
If we talk specifically about the XX regulator for the VAZ 2110, then there are several key signs by which a fake can be distinguished from the original. Be guided by these data so as not to accidentally install a device of dubious quality and origin on your car.
Fake and original
- On fakes, the black body made of metal is 1 millimeter shorter than the real part.
- In the case of the fake, the three white rivets on the case have no heads. They must be present in the original. And the diameter of the caps is 3 millimeters.
- On fakes, the spring is made in white and has more frequent winding. In the original, the coiling is less frequent, and the spring itself is black.
- Pay attention to the rubber ring of the regulator. On fakes it is black and thin, but in the case of a real part, a reddish tint is noticeable. Plus the thickness is greater.
- Take a closer look at the tip. In fakes it is darker compared to the original spare part.
- There are no markings on the counterfeit packaging; the boxes are noticeably different in appearance.
- The original yellow sticker located on the case must have an outer frame. Manufacturers of counterfeits apparently forgot about it.
Article on the topic: Does the engine on the VAZ 2114 get hot?
As you can see, recognizing a fake is not difficult. You just need to be more attentive to details.
The difference is in the boxes
Main reasons
As noted above, there are many factors that ensure the occurrence of the characteristic in question. For example, instability of speed when idling is on can provoke failure of the mass air flow sensor.
Sensors can also be “naughty”:
- speed;
- throttle position;
- crankshaft
A problem with speed is often caused by the idle speed control, as well as faulty spark plugs, air filter, wiring, etc.
Next, we will consider all the options in more detail.
How stable the VAZ-2110 operates largely depends on the correct functioning of the mass air flow sensor, because it is responsible for creating the optimal fuel-oxygen mixture. Device failure is caused by excess fuel or air. Regardless of this, starting the power plant in normal mode becomes impossible.
Signs of a malfunction of the mass air flow sensor are as follows:
- fuel is consumed more actively and usually with less efficiency;
- the engine starts unstably or does not respond to the starter at all;
- the motor malfunctions while driving;
- when the vehicle is idling, the revs fluctuate.
It is not difficult to make sure that the problem is in this sensor. For this:
- turn on the ignition of your VAZ-2110 car (but not the engine);
- take a multimeter;
- set its scale to DCV 20 volts;
- find the mass air flow sensor (under the hood, at the outlet of the air duct corrugation);
- connect the red probe to the yellow wire or the one located closest to the windshield (pierce the rubber band);
- to green (central) - attach black;
- take readings.
If the multimeter shows from 0.99 to 1.03 volts, then everything is in order with the sensor. Otherwise it is changed.
Floating or unstable idle speed on VAZ-2110, 2111 and 2112 main reasons
Today we will look at the main reasons why idle speeds fluctuate on the VAZ-2110, VAZ-2111 and VAZ-2112, the engine is unstable at idle .
One of the most common problems for owners of tens is to understand why the engine floats or does not idle. At the same time, the most unpleasant thing about this scourge is not that repairs require large financial costs to eliminate, but that there are a lot of reasons that, to one degree or another, can affect idle malfunctions on engines of the tenth family, and their search can be very labor-intensive and time-consuming work.
So, let's look at the main ones. The first and most common cause of floating idle speed is a malfunction of the mass air flow sensor (MAF). You can check the mass air flow sensor using the method described in this article - What is a mass air flow sensor and how to check the mass air flow sensor for a malfunction?
It would also be useful to check the serviceability of the idle air control - see what it looks like and where it is located in 2110, see the photo below.
Another sensor that has problems with idle speed and not only is the crankshaft position sensor (CPS). If it fails completely, the car will not start at all, but if there are bad contacts in the sensor area (and this is a common problem), such symptoms are quite possible.
The sensor itself is quite reliable; carefully inspect the wiring around it. It also wouldn’t hurt to check the entire intake system for air leaks (including the vacuum seal). Be sure to thoroughly clean the throttle body on your vehicle.
At the same time, check the TPS (throttle position sensor). It should also be noted that many people do not pay attention to the condition of their high-voltage spark plug wires. Sometimes in the dark you can observe some kind of “Tesla” effect under the hood. Well, I hope that no one forgot to check the condition of the spark plugs. After all, spark plugs also require periodic replacement and maintenance, especially with our fuel quality.
By the way, do not forget about such basic things as the condition of the air filter - if it is clogged, then you are guaranteed problems with the normal operation of the engine. After all, he is directly involved in mixture formation, and many simply forget about it. We hope that our small manual will help you find and eliminate problems with idling on your car of the tenth VAZ family
