Many VAZ-2112 owners may have experienced that the speed starts to fluctuate at idle. But not everyone knows why this effect occurs. In this article, we will consider the main malfunctions, as well as methods for eliminating them.

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 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:

1. The problem lies in the injection.
2. Unstable ignition operation.
3. Bad fuel.
4. The sensor () has failed idle move.
5. Error .

Method for eliminating floating speed on a 16-valve VAZ-2112

Before moving on to eliminating the causes, it is worth noting that untimely repairs can lead to the engine will achieve the start-stop effect. This means that the engine will start and immediately. 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 old 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, if necessary, repair or replace.
• , which may be clogged due to low-quality fuel.
• Check and. If necessary, .
• Check fuel rail sealing.
• Conduct injector wiring diagnostics.

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 (), high-voltage wires or a lock can affect this effect. Therefore, it is necessary to diagnose these particular components and parts, and, if necessary, replace them.

The idle speed sensor may be the main cause of floating speed

Throttle

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

conclusions

Diagnosing and eliminating the cause of floating idle speed for the VAZ 2112 is quite easy and simple, but this operation may not be feasible for every motorist. Therefore, it is recommended that if a malfunction occurs, contact a specialized car service, but as practice shows, car enthusiasts usually cope on their own.

The question of why the idle speed is floating is perhaps the most frequently asked question regarding the engine. Indeed, problems with idle are a common occurrence that car owners have to deal with.

The most unpleasant thing is not that this is very serious or that repairs will be too expensive and time-consuming, but that there can be a lot of reasons why the idle speed is floating. In this article I will try to help you find and eliminate the cause of unstable engine speed, so that you save your time and nerves.

We are looking for the reason why the idle speed on the VAZ 2110 is floating

1. The first thing I recommend paying attention to is the mass air flow sensor (MAF or flow meter). Read how to check the mass air flow sensor.
2. The second “suspect” usually becomes the idle air regulator (IAC), if after checking the flow meter you find nothing.
3. After this, inspect the wiring of the speed sensor (DS). Read how to check and replace the DS.
4. The next sensor that can cause floating idle speed is the crankshaft position sensor (CPS). The sensor itself is unlikely to have failed; most likely the reason is in the wiring or chip. If you don't find anything strange in the wiring.
5. The throttle assembly can also often affect the idle speed, so it would not be superfluous (position sensor throttle valve), as well as the throttle valve itself, it may need cleaning. I wrote how to clean the throttle valve.
6. Candles, high voltage wires and the ignition module can be the cause of the problem with idle, so first of all, and then and.
7. Engine idle speed fluctuates often due to a faulty idle speed solenoid valve. To test this valve, remove power from it, then turn on the ignition and connect the power wire to the contact on the valve. In this case, you should hear a distinct click; if this does not happen, connect the wires to the contact that is connected to the “positive” terminal of the battery. Even if you do not hear a click, you can conclude that the valve is faulty. If there is a click, but the engine speed fluctuates as before, check its jet.

Among other things, check the condition it is in; it may need to be replaced. Make sure it works properly and there is no air leak.

If the tips and recommendations described above do not produce results or you are not sure that you can cope with such work, seek help from professionals; specialists will quickly and accurately determine the source of the malfunction and stabilize the floating idle speed of the engine.

Thank you for your attention, I will be glad if it helps someone. If you know other reasons or methods of verification, you can safely add to this article using the comment form. Until we meet again, take care of yourself and your car.

VAZ (Lada) 2112 1999 - 2008

Car VAZ 21124, 1.6, 16 valves. A problem has arisen: the check light comes on and the car sometimes jerks, especially when it is cold. At first it’s like there’s a failure (the car is choking), then after a while it rushes on its own, as if it’s broken off the chain.

I went for diagnostics, it showed an error on the oxygen sensor, it showed a lean mixture. He says change it. I borrowed a known good sensor from a friend and installed it and the car began to operate at high speeds. I turned it off to restart it, but the car began to stall completely, and the check never stopped lighting. What could it be?

Mass air flow sensor, IAC, DPS, DPKV are new, rail pressure is normal, I changed the fuel pump mesh, air filter I changed it, cleaned the throttle, cleaned the injectors, it still didn’t help. What else can affect a lean mixture? As I understand it, the DC shows an error, but in fact the problem lies elsewhere?

In general, having unscrewed the DC valve, I noticed that it was black in color, the engine was not running smoothly at idle, but after driving for some distance it began to jerk. I let off the gas, the speed runs at high speeds, 1300-1500 rpm, the compression in the engine is 11-11.5. The vacuum brake booster is new, unscrewed the spark plugs with a white coating (as I read on the Internet, this indicates a lean mixture). What else could be in our miracle VAZ car? Honestly, this problem has been tormenting me for a long time)

Yes, it’s difficult to advise anything, since a lot of things have already been done and a lot of things have been replaced. Judging by the spark plugs with a white coating, your engine has a lean mixture. Having excluded all the sensors you replaced, we can only assume that there is an unaccounted air leak. I hope that you have already replaced the spark plugs with the onset of cold weather; they should always be installed with new ones before winter so that the engine starts more reliably.
Check vacuum hoses for intake manifold and other connection points (receiver, manifold to the block, injector connection points, for example oil seals, rings do not fit tightly). When installing injectors, the sealing rings must be lubricated, for example, with diesel fuel. Otherwise, when dry, they can be torn or placed askew, and that’s where you get air leaks or fuel leaks.

How did you clean the injectors? If you removed it from the engine as required and took it to a service station to wash it, then this is correct, you could also see the spray there.

If you used a wash that is poured into the tank, then this is not always useful, even often the effect is the opposite: the dirt in the tank is washed off and rushes to the engine, and there it can very successfully clog the injectors more. And in your text I did not see information about the adsorber sensor. If it is faulty, then there may be engine interruptions at certain moments.
I read about replacing the IAC and TPS. Doesn't the throttle valve itself stick the moment you let off the gas pedal? Or is the cable slowing down in the sheath? You may have checked this, but the description of your question does not contain this information.

And after you replaced the DC, did you check the error number? She could have changed, that’s why the check remained lit.
But in fact, the error in lambda could not be in the sensor itself, but, for example, in poor contact on the connecting block of the wires.
Please provide the error number.

You also need to check the wires and connectors for the oxygen sensor, air sensor, air sensor, check the operating parameters of the coolant temperature sensor, it is advisable to drive with a scanner connected and check the parameters of the engine sensors at the time of malfunction. It is also worth checking the cleanliness of the ECU connector contacts; the problem may also be in the ECU. By rich mixture The reasons are described, you can also check the spray pattern of the injectors on the stand.

Almost every owner of a domestic VAZ has encountered the problem of high idle speed. That is, when starting the engine, the speed is increased as expected, but when the engine warms up, it does not drop below 1500 or 1000 revolutions, which is not normal. There may be several reasons for this, including a malfunctioning TPS and idle air control.

To fix the problem, you should diagnose the main components and components that affect the increase in speed.

Why might there be high idle speed?

One of the main reasons may be the failure of the IAC, the idle air regulator, which is responsible for adjusting the engine speed at idle. At , the speed can “float”, rise and fall spontaneously. If the sensor completely fails, the car may simply stall at idle.

Also, increased speeds can be caused by a malfunction of the throttle position sensor (TPS). Over time, moisture gets under the sensor, which leads to the formation of oxide and rust on the regulator rod. To check this, you need to unscrew the sensor and carefully inspect it and the rod. If rust is found on them, they should be treated with penetrating lubricant or WD 40.

Typically the problem increased speed on the VAZ 2110-12 lies precisely in these two sensors. Therefore, first of all, you need to pay attention to them.

Where are the IAC and TPS sensors located?

So, first, let's check the IAC sensor. It is located on the throttle assembly below the TPS sensor. Dismantling it is very simple - remove the block from the sensor and use a Phillips screwdriver to unscrew the two bolts securing it. Then we pull out the sensor or perform diagnostics on it, read about this below.

The throttle position sensor is located above the IAC and is also secured with two bolts. It unscrews quite easily; there is no need to remove either the pipe on the throttle or the throttle itself. Disconnect the block, unscrew the two bolts and pull out the sensor.

To make sure that the problem with high speed is really in one of these sensors, and maybe in each other at once, you should diagnose them.

Diagnostics of the IAC sensor 2110

There are several ways. To check we need a multimeter. First, let's describe the simplest way:

IAC check method 1

1. Disconnect the block from the sensor and unscrew the sensor
2. Turn on the ignition
3. We connect the block to the removed sensor, the needle in the sensor should move out, if not, then the sensor is faulty

IAC check method 2

1. Disconnect the negative terminal of the battery
2. Using a multimeter, we measure the resistance of the external and internal windings of the IAC, while the resistance parameters of contacts A and B, and C and D should be 40-80 Ohms.
3. If the instrument scale is zero, it is necessary to replace the IAC with a serviceable one, and if the required parameters are obtained, we check the resistance values ​​in pairs B and C, A and D.
4. The multimeter should detect an open circuit
5. With such indicators, the IAC is serviceable, and if they are absent, the regulator must be replaced.

IAC test method 3

1. Disconnect the block from the sensor
2. Using a voltmeter, we check the voltage - the “minus” goes to the engine, and the “plus” to the terminals of the same block of wires A and D.
3. The ignition is turned on and the received data is analyzed - the voltage should be within twelve volts, if less then there is most likely a problem with the battery charge, if there is no voltage, then you will have to check and the electronic unit control, and the entire circuit completely.
4. Then we continue the inspection with the ignition on, and analyze terminals A:B, C:D one by one - the optimal resistance will be about fifty-three ohms; During normal operation of the IAC, the resistance will be infinitely high.

Diagnostics of TPS VAZ 2110

To diagnose the sensor we need a voltmeter.

1. It is necessary to turn on the ignition and check the voltage between the slider contact and the minus with a voltmeter. The voltmeter should read no more than 0.7 V.
2. Now you need to turn the plastic sector, thereby completely opening the damper, then measure the voltage again. The device must show at least 4 V.
3. Turn off the ignition and disconnect the connector from the sensor. We check the resistance between the slider contact and some terminal.
4. Slowly, turning the sector, monitor the voltmeter readings. Make sure that the needle moves smoothly and slowly; if you notice jumps, the throttle position sensor is faulty and must be replaced.

Symptoms of TPS malfunction

• Deterioration of vehicle dynamics
• Floating idle speed
• Jerking during acceleration
• Increased idle speed
• The engine may stall at idle

If one or more of the above symptoms are detected, the sensor should be checked and diagnosed in the manner described above.

Which TPS sensor to choose for replacement

• DPDZ /2110/ GM 2112-1148200 price from 300 rub.
• DPDZ /2110/ PEKAR 2112-1148200 price from 200 rub.
• TPDZ /2110/ StartVOLT VS-TP 0110 price from 200 rub.
• TPDZ /2110/ HOFER HF 750260 price from 150 rub.
• DPDZ /2110/ CJSC Account Mash 2112-1148200-05 price from 400 rub.
• DPDZ /2110/ JSC RIKOR ELECTRONICS 2112-1148200 price from 300 rub.

Replacing the Throttle Position Sensor on a VAZ 2110

Using a Phillips screwdriver, unscrew the two sensor mounting bolts, disconnect the block and remove the sensor.

If traces of rust or oxidation are found on the rod, which regulates the speed, it is necessary to clean it with penetrating lubricant.