Engine speed does not drop at idle: how to fix the problem. Engine speed does not drop at idle: we are looking for the cause and fix it Engine speed does not drop immediately

In the process of operating a car, drivers have to face various problems. One of the faults, which is quite widespread, is the constant maintenance by the engine high revs... That is, even on Idling engine speed does not drop. Such a problem can be observed in both injection and carburetor engines, but the reasons for this will be different. Within the framework of this article, we will consider what kind of malfunction this problem is, and how you can get rid of it.

Table of contents:

How to diagnose that idle speed is not falling

Even an inexperienced driver can easily notice that the idle speed of the car does not drop. This is easy to determine by ear, since, as you know, the lower the rpm, the quieter the engine runs. In addition, if the car is equipped with a tachometer, it can be used to determine the number of revolutions per minute at a particular point in time.

Depending on which engine is installed in the vehicle, the idle speed may vary. On average, it is generally accepted that the engine is operating normally when the idle speed is between 650 and 950 rpm. If the turnover is higher (unless otherwise stated in technical passport to the vehicle), then this can be called a deviation.

Please note: On most vehicles with injection engines, the Check Engine light on the dashboard comes on at high idle speed.

What are the risks of high idle speed

The first thing a driver should remember is about high flow fuel at high speeds. Accordingly, if high revs are maintained at idle, this means that part of the fuel "flies into the pipe". Moreover, this problem directly affects the resource of the engine, which suffers as a result of such a malfunction. The node itself, which led to the occurrence of the malfunction in question, may also suffer. That is why, if this problem is identified, it should be eliminated as soon as possible.

Why the idling speed of the carburetor engine does not fall

At the moment, carburetor engines are practically not used in modern cars... However, it is necessary to consider why there may be a problem with high idle speed in such engines, since most of the problems overlap with injection engines. In the event of such a malfunction, you should pay attention to the following elements:

Most of the problems that lead to high idle speed in a carburetor engine are discussed above. Also, a common problem for carburetors and injectors cannot be ruled out - jamming of the gas pedal.

Why the idle speed of the injection engine does not fall

Now let's look at the malfunctions that lead to increased idle speed in an injection engine. Unlike carburetor engines, where all the problems are of a mechanical nature, a malfunction in the injector may be associated, among other things, with improper operation of the electronics. The main reasons are as follows:

As you can see, there are a lot of problems due to which the idle speed does not decrease. If such a malfunction occurs, you should start looking for its cause as soon as possible in order to prevent even more serious problems.

The owners of front-wheel drive VAZs have enough troubles during the entire operation of the car. One of the most annoying is the high idle speed, moreover, on an already warmed up car. This problem is usually frustrating because there are too many reasons for its occurrence, and it is not easy to find them.

Let's list them.

The most basic is a malfunction or failure of the mass air flow sensor.
Breakdown of the idle speed control valve occurs at least as often.
A crankshaft position sensor giving incorrect information to the control unit can also become the root of high or floating idle speeds.
The position sensor may also be to blame. throttle.
It happens that for some reason the gas pedal does not return to the end. Moreover, this happens both because of a banal malfunction of the cable, so because of something completely ridiculous - for example, after washing the car, the driver's mat was covered so that the tip of the mat began to touch the pedal.
Heavily clogged air filter... Because of this, the combustion mixture turns out to be too rich in gasoline, again there are high rpm during idling.
The cable flew off the throttle.
Defective engine temperature sensor. It gives incorrect values to the "brains" of the car, they increase the speed of the crankshaft, thinking that the engine is cold.

As you can see, we have before us a whole forest of various reasons why high turnovers appear! Next, we will take a closer look at the most typical, plus the most common problems associated with the described problem. At the same time, we will figure out how to eliminate them with our own hands.

Ways to eliminate the "sore"

If such a nuisance occurs, it is necessary to search for which node is to blame analytically, checking all the indicated sensors.

To begin with, consider the following option for correcting the problem situation. Suppose high revs were found at the VAZ 2110. Inspection of the suspects for faulty components showed that the throttle position sensor has traces of rust. It is located directly above the throttle valve. Measurements with a voltmeter showed that when the motor is idling, the voltage on it remains high, which means that it does not close the damper.

How do I fix the problem? For this we only need a screwdriver. We proceed to the implementation of the procedure.

Disconnecting the terminal block, as well as unscrewing two screws, dismantle the assembly.
We notice that traces of rust inside interfere with the movement of the wheel that adjusts the position of the damper.
We fill the insides of the defective device with a penetrating anti-rust aerosol.
Scroll the wheel with a screwdriver for development.
We assemble in the reverse order.

Checking if it is high now idle speed engine. The problem should be fixed.

Now let's look at another case. Let's say we have an overestimated idle speed at a VAZ 2114. This is what we do when faced with this situation.

When clarifying the circumstances of the problem under study, we initially always check the operation of the idle sensor. This device consists of a needle embedded inside an electromagnetic coil. The needle either moves inside the coil, moving away from the orifice of the throttle tube, or extends, closing this hole, thereby stopping the supply of air for combustion of the mixture.

Also read about and.

This element is located at the throttle valve, opposite the gas pedal cable. To diagnose it, we pull out the terminal block from it, start the car, after which we see that our high engine speed has not changed at idle. Then we remove this defective unit, then we clean it or replace it. For work we take:

screwdriver;
a toothbrush;
petrol.

Begin.

We unscrew the two screws. We take out the broken knot.
We connect the wiring to it. We turn on the ignition. If the needle of the device is slightly pushed into the coil by touch, then it is serviceable.
If the needle does not respond when an electric current is applied, wash the device with a toothbrush with gasoline.
We assemble in the reverse order.

When you cannot restore the functionality of this unit with your own hands, it is better to purchase a new one. Moreover, the cost of the spare part is low.

Other ways to fix

Of course, the options considered do not exhaust the possible ways of correcting the drawback when high revs are noticed on a warm engine. To further explore the most common situations, let's look at the case of a malfunctioning mass air flow sensor.

This device is responsible for supplying the correct portions of air for combustion of the mixture, as well as supplying data to the unit electronic control about these portions so that the unit can match the supplied portions of gasoline.

Diagnostics of this node can be made as follows. It is necessary to disconnect the terminal block from our mass flow regulator, and then start the engine, after which you need to drive at speed crankshaft above 2000 rpm.

This automatically starts emergency mode, the portions of the mixture are now calculated only by the position of the damper. If the sensations showed that the car with the disabled sensor became more dynamic than with the connected one, then the malfunction of this unit is obvious.

To replace it, take the following tools:

Phillips screwdriver;
flat screwdriver.

We are starting repairs.

After muffling the engine, disconnect the wires from the MAF sensor.
After loosening the clamp, remove the hose on the inlet pipe.
We dismantle the defective device by unscrewing two bolts.
We are replacing the device.
We do the assembly, moving backwards point by point.

This is how this cause of high revs is eliminated.

For some reason it didn't help

Now let's look at another such situation. The car owner changed, for example, the idle sensor, while the crankshaft revolutions became high, or they still remained elevated.

The reasons for this unpleasant phenomenon may be as follows.

Most likely, the car enthusiast made a replacement just like that, at random, maybe he would stop turning too quickly. The real situation things suggests that the fault must be looked for elsewhere.
If this is not a completely new sensor, it has an adjusting bolt, it may need to be tightened to adjust the problem node. Modern idle valves, when installed, do not need any additional adjustment. However, for example, if Priora has a high idle speed, then you can look for an adjusting screw for this car.
It is possible that the new spare part turned out to be defective.
The new part is incorrectly installed.

Here, perhaps, all the roots of the phenomenon are listed.

Let's talk about the cost

Not everyone can do this type of repair, like even reinstalling a sensor. Although the main difficulties are caused not so much by the substitution of one of the sensors involved in the process, but by the diagnostics of the sources of the overestimation of the crankshaft speed when idling. After all, we found out that the search for the causes of this disease is complicated by their diversity.

If the car enthusiast decides to contact the service station masters with a request to find the reason for the high engine speed produced at idle speed, then the cost of diagnostics in large cities of the Russian Federation will be as follows.

Town	Price
Moscow	RUB 700
St. Petersburg	650 RUB
Ekaterinburg	RUB 500
Samara	RUB 500
Krasnodar	RUB 550

Since the price of manipulation is low, then if the car owner doubts the success of his own diagnostics, he can safely contact the service station.

In the course of the article, we examined the main options for solving a common problem. Now, if a car enthusiast is faced with a manifestation of an overestimated idle crankshaft speed, he will already know what to do.

Now read about and.

Often, car owners are faced with such a malfunction when the engine speed does not fall when the gas is released, or rather, does not fall to the normal idle speed (XX). This applies to both the fuel injection system and the carburetor one.

Usually idling gasoline passenger cars mobiles, depending on the motor model, are in the range of 650-1000 rpm. Any deviations from these indicators indicate incorrect operation of the vehicle's power supply system. It is not worth delaying with the elimination of this malfunction, since increased engine speed leads to an increase in fuel consumption in the car and acceleration of engine wear, which negatively affects the financial condition of the driver.

Sometimes the reason may lie in the excessive enrichment of the fuel-air mixture supplied to the cylinders. This provokes an increase in revolutions to a certain level, after which the engine begins to "choke", thereby reducing the revolutions to a normal value, after which they rise again. This malfunction causes the effect of "floating speed", but the problem may lie in other malfunctions of the power system. In addition, do not forget that malfunctions in cases with injection and carburetor engines will be different.

Major engine problems with a carburetor power system

The location of the needle valve, which is responsible for adjusting the level of gasoline in the float chamber.
Loose closure of the throttle valve, which often happens when it is clogged or mechanically damaged. A contaminated valve should be cleaned with a cleaning product available from an auto parts store. And in case of mechanical damage to this unit, most often, it is required complete replacement carburetor.
Incorrect adjustment of the XX system. This problem often appears after cleaning or replacing the carburetor. To eliminate it, you just need to adjust it, ensuring the optimal ratio of gasoline and air in the fuel-air mixture.
A consistently high idle speed may indicate a leaky closure of the throttle valve located in the primary chamber. This problem appears due to wear on the throttle cable or deformation of the valve itself.
Damage to the intake manifold or wear on the gasket between the cylinder head or carburetor.

In case of injection system nutrition, possible reasons the increase in idle speed is noticeably greater. This is due to the fact that they can be associated with both the failure of mechanical components and the malfunction of electronic sensors.

The main malfunctions of the injector

Coolant temperature sensor malfunction... Interruptions in the operation of this sensor lead to the fact that the motor constantly operates at increased speeds, in the warm-up mode. In this case, after warming up the power unit to operating temperature, the electronic control unit does not drop the speed to normal values, since the sensor signals that the engine has not yet warmed up. The same happens if the idle speed regulator does not function properly.
The throttle cable is stuck. This happens especially often on vehicles with high mileage.
Malfunction of the XX regulator or its electronic sensor, while idle speed may increase or disappear altogether.
Throttle position sensor malfunction.
Jumping or excessive stretching of the return spring, which should return the damper to its original position.
Violation of the integrity of the gaskets, rubber seals of the injectors or the manifold itself. In the event of these malfunctions, excess air from the environment enters the combustion chamber.

The most commonplace reason that the engine speed does not drop to idle when the gas is released may be the careless placement of the mat under the accelerator pedal after visiting the car wash.

Let's summarize

First of all, a malfunction of the injection and carburetor power system should be diagnosed with an inspection of the throttle valve.

In case of injection engine, to pinpoint the malfunction of a specific sensor will help computer diagnostics... To do this, it is best to use the services of a service that specializes in servicing cars of a particular brand.

Drivers often wonder why the engine idle speed does not drop. This situation is quite common, and neither carburetor engines nor a more modern injector. True, the reasons for the malfunction will be different for them. But, in practice, everything can be diagnosed independently, and also on almost all car models, the problem can be eliminated by hand without much difficulty. The most important thing here is to correctly diagnose, this will significantly speed up the repair process, and save you from additional problems and difficulties.

What it is?

Why does the engine idle speed not drop? First, let's figure out how to understand that there is a problem, and also see what it can lead to. Even an inexperienced motorist can determine the increase in idle speed. It can be easily felt by ear. With an increase in revolutions, an increase in the noise of the engine running is observed when the gas pedal is released. Also, on cars equipped with a tachometer, you can track the increase in revolutions on the device. On almost all models of passenger cars, idle speed fluctuates within 650-950 rpm(check the indicator in the technical passport of your car), everything above is considered a deviation from the norm. Also, on many injectors, this problem is caused by the inclusion of a "check" on the panel.

In any case, you should try to fix the problem as soon as possible. Higher revs are the reason for an increase in fuel consumption. This increases the cost of refueling. Also, an increase in revs significantly accelerates engine wear. So it is not advisable to delay the solution of this problem. This will save you a lot of money. When identifying and eliminating the cause of high revs, it should be remembered that on carburetors and injectors, the problem can be caused by various malfunctions.

Carburetors

First, let's deal with the problem on carburetor engines... This type of power supply is considered obsolete, but there are still many vehicles on the road that are stocked this way. Also, many motorists, for their ideological reasons, use such motors, and are not going to give them up. It is quite difficult to diagnose the source of the problem here, and this is given the small list of items causing an increase in revs. Let's take a look at what you should pay attention to:

Needle valve engagement... In this case, the fuel enters the chamber in a non-metered manner. Moreover, depending on the location in which the valve is jammed, idle speed can both disappear and vice versa increase;
Violation of regulation idle system. This usually happens after cleaning or repairing the carburetor. To avoid problems, the ratio of fuel and air should be set correctly. If you have not previously produced, then it is better to read how this is done exactly on your version;
Closing problem. There may be several reasons for such a malfunction. Most often, the damper does not close due to the presence of carbon deposits on it. In this case, you will need to clean this node. This usually helps. In some cases, the throttle valve can be damaged. Then you will need to change this part, but not all carburetors have this option;
Sometimes, the problem can appear when, this happens quite rarely. But, it's still better to check. To do this, with the engine running, open the radiator cap; with a burned-out gasket, white smoke will come out of the neck. In this case, you will need to change the gasket;
Open suction... Check how the damper in the primary chamber works. If you have identified a problem, then it makes sense to see how the suction works. Most often, to fix the problem, it turns out to be enough just to lubricate the cable and the damper drive.

In addition, jamming of the gas pedal may occur. This situation can happen not only on carburetors, but also on injectors. Be sure to check if the pedal moves freely.

Injector

On engines equipped with injectors, there are more possible reasons for increased revs. In particular, the problem can be caused by both mechanical failures and the failure of electronic sensors. But, unlike simpler carburetors, it is simplified by the presence on-board computer that is capable of reading errors. So, let's consider the reasons for the increase in speed on the injectors:

Refusal . If this sensor breaks down, power unit starts to work non-stop in the warm-up mode, that is, the revolutions are not reset. The control unit considers that the optimum operating temperature has not yet been reached and tries to heat the unit. Such a malfunction is fraught with engine overheating and costly repairs. The easiest way to identify this problem is through computer diagnostics;
Disruption of work. Sometimes, the cause is the mass air flow sensor. Again, they make diagnostics, after which they check the suspicious sensors with a multimeter. An additional check is required to ensure that there is no open circuit in the wiring. If necessary, faulty sensors are changed;
Throttle cable sticking may occur. Check if it works. If a malfunction is identified, it is recommended to try to lubricate the cable and develop it. If it does not help, then you will have to replace the part completely;
The damper return spring has jumped off or is too stretched. This problem is also common in older vehicles. Replace the spring. If it is stretched, then you will need to buy an injection repair kit;
... In this case, it sends a signal to the engine control unit about the open throttle, in turn, the "brains" of the car provide more revolutions than it actually needs. The cause of the breakdown may be a simple jamming of the part, or a burnout of the resistance. In the latter case, only the option with replacing the sensor is possible;
The last reason to check is integrity injector gaskets... The check will require a fairly serious intervention in the injector, therefore, this reason is checked last, although this phenomenon is not the rarest. If the gaskets are damaged, excess air enters the combustion chambers, which causes an increase in engine speed.

In addition to all of the above, always monitor the location of the mat in the car, sometimes it gets under the pedal and does not allow it to work optimally.

Conclusion... Every motorist has encountered problems with the operation of the power system at least once. Therefore, such a question as to why the engine speed does not drop at idle is not surprising. Unfortunately, it is almost impossible to answer it unequivocally. There are many reasons for this behavior of the car. To identify and eliminate the breakdown, you will have to carry out detailed diagnostics.