Do not fall momentum. Why do not turn the engine speed and what to do. Why do not fall at idle driving engine

The high speed of the engine at idle, except for completely unnecessary fuel reproduction, also interfere with driving cars - let's say, when driving a particularly broken section of the road, when you want to gently "sneak" among the selected on the first gear, and the car boldly takes the suspension strikes. In addition, with long downtime in traffic jams, the motor will work all the time in elevated temperature mode.
Consider several reasons why the increased speed of idling on a heated engine is not falling. The reasons may be faulty in both the mechanical and in the electronic components of the engine power system, so we describe the possible breakdown options separately. But since in the car these components interact in the complex, then you may be able to independently find the answer to the question why your engine has large idle speeds by taking the material of this article as "information for reflection".

Checking the intake manifold for tightness

The redundancy of excess air may cause high idle speed. Moreover, depending on the place of penetration of excess air in the intake manifold, idling turns either will be simply elevated, or will begin to "swim".

If idling "float", then most likely takes place.

If there is simply disruption of the tightness of the intake manifold gaskets, damage to vacuum hoses or sealing rings, the turnover will "swim". This is due to the fact that the amount of gasoline supplied to the cylinders will be permanent, and the quality of the mixture becomes the "richer", then "poorer". When a certain critical value (air content in the fuel mixture), the motor will start slowing down - up to the stop. But with a decrease in the number of revolutions, the amount of air entering the collector will decrease, i.e. the mixture will encine and the engine "comes will be limited" - idling turns will increase. So it will continue until not eliminate the tightness of the intake manifold.
On turbocharged engines, air drums can also be performed through damage in the intercooler or connection of air nozzles. With a significant subsoil (for example, if screwed off the nozzle from the intercoule), the engine begins to work with a whistling (or hissing) sound. But sometimes it is possible to identify the place of impairment of the intake path, overlapping the air supply to the intake manifold in different places in turn - from the air filter to the collector itself.

Supply of excess fuel

Cleaning throttle valve

A completely different situation will turn out if not just an excess air, and the fuel and air mixture - for example, through a slot formed as a result of a loose closure of the throttle. In this case, highly idle engine turnover will be stable.
In the fuel systems of some engines there is a semi-automatic regulation of fuel supply in the engine warming mode - due to its large idle speeds are maintained until the motor is warmed to a given temperature. Fuel is served on the channel, "bye" throttle.
Such a channel can close / open in various ways - the valve in it has either an electric drive (solenoid), or it can be arranged like a refrigerator thermaller - when the engine warms up, the channel is locked.

With high idling, it is necessary to check the entire throttle node with sensors and the XX regulator.

In any case, such a valve may break, and then in the intake manifold will always come with excess fuel, which will be the cause of larger idle speed after the engine warms up.
In all such cases, first of all, it is necessary to remove the body of the throttle valve and rinse with it with a special solution - a lot of things are sold in stores of such "chemistry". After washing, you need to thoroughly inspect the node - especially for the subject of hot or, on the contrary, excessive throttle of the throttle valve.
The throttle valves of some injection engines have, in addition, the screw for adjusting the idling of the engine or restrictions on the closing of the damper - you should pay attention to them, - is the adjustment node.
Often the engine speeds are not falling at idle due to the hot gas cable or falling under the pedal of foreign objects - the corner of the rug, for example.
Of course, almost all of the above can relate to carburetor motors. In addition, a characteristic malfunction (or, more precisely, deviation from the norm) for them is the incomplete opening of the air damper - mainly due to improper installation of the "Suppress" cable. In the absence of a breakdown, normal speeds at idle the carburetor engine are installed by adjustment using two screws - "quantity" and "quality" of the mixture.

Files of electronics

Checking the engine idle regulator

After replacing the idling regulator, it must be "prescribed" i.e. Apply its parameters in memory of the ECU.

The idling regulator (RXX) is a stepper motor (solenoid), operating from pulse signals supplied. It works in a similar manner with a screw adjustment screw of the mixture in the carburetor - when extending the valve it overlaps the fuel channel when it opens it.
It often happens that the core of the regulator simply encourages, and it ceases to respond to the signals of the ECU. And it is possible to damage the idling regulator yet in the store when buying - trying to turn or press the valve to the needle.
If, after replacing the sensor (regulator) of idling, there are high speeds, then, most likely, the case or in the ECU or in the mass flow sensor - all components of the power system elements are operated in the interaction, and must be diagnosed. It is quite possible that a new regulator will have to "prescribe" - that is, to enter the message to the computer.

temperature sensor

This sensor can also affect the engine fuel system. Having groaning an invalid signal (appropriately reduced) on the ECU, it will cause the controller to give a signal to other elements of the fuel system (nozzles incl.) On the enrichment of the mixture. The incorrectness of the sensor signal will lead to the fact that at idle turns will be more than 1000 min-1.

Air Flow Sensor

The DMRV directly affects the quality and the amount of mixture supplied to the cylinders - because the ECU "knows" about its composition thanks to this (and some other) sensors.
In conclusion, if the engine of your car was unfortunately climbing idling, look first in the possible hotels of the fuel system mechanisms - after all, it is primarily subject to different contaminants, and for electronic nodes, a voltage or closure is much more dangerous.

Often drivers are interested in why engine speeds do not fall at idle. This situation is quite often occurring, and no carburetor engines or more modern injectors are not insured. True, the causes of malfunction will be different. But, in practice, everything can be diagnosed on their own, as well as almost on all models of cars, the problem is eliminated with their own hands without any particular difficulties. Here the most important thing is to correctly diagnose, it will significantly speed up the repair process, and will save you from additional problems and difficulties.

What it is?

Why don't the engine speed fall at idle? For a start, let's decide how to understand that the problem arose, and also let's see what it can lead to. To determine the increase in speed at idle can even inexperienced car enthusiast. It is easily felt by rumor. With increasing revolutions, there is an increase in the noise of the operating engine when the gas pedal is released. Also on the machines equipped with a tachometer, you can trace the increase in the revolutions. Almost on all models of passenger cars, idle turns fluctuate within 650-950 revolutions per minute (Specify the indicator in those. your passport of your car), all that is considered to be a deviation from the norm. Also on many injectors such a problem causes the inclusion of "Check" on the panel.

Carburetrators

To begin with, we will deal with the problem on carburetor engines. This type of food is considered obsolete, but still many cars on the roads are accurately so. Also, many motorists in their ideological reasons use such motors, and are not going to refuse them. Diagnose the source of the problem here is quite difficult, and this is taking into account the small list of elements that cause an increase in revolutions. Let's look at what should be paid to:

• Loading needle valve. In this case, the fuel enters the chamber is not dosed. Moreover, depending on the location in which the valve jammed, idle turns can both disappear and vice versa increase;
• Violation of adjustment idling systems. It usually occurs after cleaning or repairing the carburetor. To avoid problems, you should correctly set the ratio of fuel and air. If you have not previously done, it is better to read how it is done on your version;
• The problem is closed. There may be several reasons for such a malfunction. Most often, the damper is not closed due to the presence of Nagar on it. In this case, you will need to clean this node. Usually, it helps. In some cases, the throttle may be damaged. Then it will be necessary to change this item, but this possibility is not provided on all carburetors;
• Sometimes, the problem may manifest itself when it happens quite rarely. But, nevertheless, it is better to check. For this, on the engine running engine, open the radiator cover, with a running gasket from the neck, the white smoke will go out. In this case, it will be necessary to change the gasket;
• Open Soots. Check how the valve works in the primary chamber. If they revealed the problem, then it makes sense to see how the sacrifice works. Most often, to eliminate the problem, it is enough to simply lubricate the cable and the damper drive.

Injector

On engines that are equipped with injectors, possible reasons for increased revolutions. In particular, the problem may be caused by both mechanical faults and the refusal of electronic sensors. But, unlike simpler carburetors, simplifies the presence of an on-board computer, which is capable of reading errors. So, consider the reasons for increasing revolutions on the injectors:

• Failure When breakdown of this sensor, the power unit begins to work nonstopable in warm-up mode, that is, the revs are not reset. The control unit believes that the optimal operating temperature has not yet been reached, and tries to heat the unit. Such a malfunction is fraught with overheating of the engine and expensive repairs. The easiest way to identify this problem using computer diagnostics;
• Violation of work. Sometimes, the reason in the mass flow sensor. Again, they are diagnosed, after which suspicious sensors are checking the multimeter. Additional check is required to eliminate the wiring break. If necessary, faulty sensors change;
• A throttle cable may occur. Check it with its performance. When the malfunction is detected, it is recommended to try to lubricate the cable, and develop it. If it does not help, you have to replace the part completely;
• Jumped, or the return spring of the flap was too stretched. This problem is also characteristic of old cars. Put the spring in place. If she stretched, it will be needed to buy an injection repair kit;
• . In this case, it serves an engine control signal of an open valve, in turn "brains" of the car provide more revolutions than in fact. The reason for the breakdown may be in a simple piece of part, or resistance brave. In the latter case, only a variant with a sensor replacement is possible;
• The last reason to be checked is the integrity sealing gaskets injectors. The check will require enough serious interference in the injector, therefore, they check this cause last, although this phenomenon is not the rare. In case of damage to the gaskets in the combustion chamber, there is an excess air, which causes an increase in engine speed.

Conclusion. Problems with the operation of the power system at least once met each motorist. Therefore, such a question is why the engine speed does not fall at idle, is not amazing. Unfortunately, it is almost impossible to answer it uniquely. There are quite a few reasons for such behavior of the car. To reveal and eliminate breakdown, you will have to carry out a detailed diagnosis.

Often, car owners are faced with such a malfunction when the engine is not falling when the engine is not falling, more precisely, they do not fall to the normal level of idling (XX). This applies to both the injector fuel supply system and carburetor.

Usually, idle speed of gasoline passenger cars, depending on the motor model, are within 650-1000 rpm. Any deviations from these indicators indicate the incorrect operation of the car supply system. With the elimination of this malfunction, it is not worth tightening, since the increased engine speed leads to an increase in fuel consumption in the car and accelerating the wear of the motor, which negatively affects the driver's financial condition.

Sometimes the reason can be wounded in excessive enrichment of the fuel and air mixture supplied to the cylinders. It provokes the growth of revolutions to some level, after which the engine begins to "chop up", thereby reducing the turnover to normal value, after which they rise again. This malfunction causes the "floating revolutions" effect, but the problem may be in other disorders of the power system. In addition, you should not forget that malfunctions in cases with injection and carburetor motors will be different.

Main engine malfunctions with carburetor power supply system

• The occurrence of the needle valve responsible for adjusting the gasoline level in the float chamber.
• The loose closure of the throttle is often happening when it is clogged or mechanically damage. The contaminated valve should be cleared with a special tool that can be purchased at the auto parts store. And with mechanical damage to this node, most often, the complete replacement of the carburetor is required.
• Incorrect adjustment of the XX system. This problem often appears after cleaning or replacing the carburetor. To eliminate, it is necessary to simply adjust it, providing the optimal ratio of gasoline and air in the fuel and air mixture.
• Stable high idling may indicate a loose closure of the throttle, located in the primary chamber. Such a problem appears due to the wear of the throttle damper cable or deformation of the damper itself.
• Damage to the intake manifold or wear of the gasket between the GBC or the carburetor.

In the case of an injection system, possible reasons for increasing idolotes are noticeably more. This is due to the fact that they can be associated both with the failure of mechanical components and a malfunction of electronic sensors.

Major malfunctions injector

• Fault Cooling fluid temperature sensor. Interruptions in the operation of this sensor lead to the fact that the motor constantly functions on elevated circulation, in warm-up mode. At the same time, after warming up the power unit to the operating temperature, the electronic control unit does not reset the revolutions to normal values, since the sensor signals that the engine has not yet warmed. The same happens with the improper functioning of the idle regulator.
• The throttle adjustment cable is hot. Especially often it happens on cars with great mileage.
• Disrupting the performance of the controller of the XX or its electronic sensor, while the turnover at idle can increase or disappear.
• Throttle position sensor fault.
• Scapping or excessive stretching of the return spring, which should return the flap in the original position.
• Violation of the integrity of gaskets, rubber seals injectors or the collector himself. With these problems, excess air from the environment falls into the combustion chamber.

The most banal cause is that when the gas is discharged, the engine revolutions do not fall to idle, there may be an inaccient placement of the rug under the accelerator pedal after visiting the car wash.

Let's summarize

First of all, the malfunction of the injection and carburetor system, you should begin to diagnose from inspection of the throttle.

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

It is very important that the engine work correctly in any mode, including at idle. However, many car owners face a problem: when the engine is discharged, the engine turnover is not reset. As soon as this defect is detected, it is necessary to immediately find out the reason and eliminate the malfunction for the uninterrupted operation of the car. Also, the engine can reset the turnover for a long time, which also does not contribute to the right job.

Usually upon reaching the operating temperature, turns should fall to its norm. Indicators for each specific vehicle model Manufacturer indicates the manual. They can change slightly depending on the mileage and the overall condition of the car, but usually hold up 650-1000 revolutions.

In some cases, turns are very slowly discharged or at all hold on at the same level in 1500-2000 revolutions. In this mode, not only the fuel consumption increases, which affects the driver's finances, but also contributes to the wear of the engine.

The cause of work failure in idle mode must be diagnosed using qualified masters. However, to independently understand why the engine turns do not fall.

Carburetor System Problems

When the gas is discharged, the drop in revolutions can pass badly both on the injectors and on the carburetor systems.

If the car is a carburetor, then there may be several defects.

Most often, turns are not reset due to the faulty throttle. When the engine warms up, it is in the open position so that more air falls into the system. Then it closes and turns should fall.

Not closed to the end, the throttle valve leads to the fact that when the operating temperature is still being reached, the re-entered mixture is still fed, and the revolutions remain at the same level. If this item is strongly contaminated or deformed, it cannot be completely closed.

You can clean the damper using a special tool, which can be purchased at the automotive goods store. The deformation may require the replacement of the carburetor completely. The valve can be loosened loosely, if the drive cable is strongly worn. His replacement can correct the situation.

Another common reason, due to which the engine speed does not fall in idle mode, becomes a laying between the carburetor and the head of the cylinder block, which has become unusable, or the damaged intake manifold.

After replacing the carburetor or cleaning the power system, it is often possible to notice that the engine turns slowly. This is due to improper adjustment of the idle system, the re-entered air-fuel mixture is often fed. To eliminate a malfunction, it is necessary to adjust the supply ratio into the fuel and air system.

Also provoke a work defect can high fuel in the carburetor float chamber. The needle valve is responsible for it. Checking this detail can correct the situation.

Injector system

If an injection system is installed on the car, the causes of high speed at idle can be significantly larger. Here, both mechanical elements and electronic devices that are responsible for adjusting the XX can fail.

The main malfunctions of the injector include:

1. Incorrect operation of the temperature sensor installed in the cooling system. Incorrectly obtained data from this instrument makes the electronics to recognize the engine as cold and work for warming up, due to which high revs required for a set of operating temperature are supported. Often, overheating may occur, which leads to more serious breakdowns, up to the overhaul of the engine. The same effect is possible with incorrect operation of the idle mode regulator.
2. The cable regulating the work of the throttle can ignite. The more car mileage, the higher the risk to face a similar problem.
3. The electronic XX operation sensor often comes into a malfunction, then turnover will be or grow or will disappear.
4. The spring, leading the throttle to the original closed position, incorrectly functions, scores or is very stretched.
5. To the combustion chamber of fuel, there is too much air due to poor-quality or past gaskets. It is necessary to carefully check the collector seals and nozzles.
6. And the most simple reason is usually the wrong arrangement of the rug after a visit to the car wash or dry cleaning of the cabin. It is often inactively placed under the accelerator pedal, which leads to the visibility of the engine improper operation.

If the car is oversaturated with a variety of electronics and all work is built on the proper functioning of the sensors, one of them may well become a problem. It will serve incorrect data on a computer, as a result, turns will not fall. Self detect the problem, most likely, will not succeed.

It is necessary to contact the car service for computer diagnostics. The best task will be cope with specialists working on a service that specializes in the repair of a specific car brand. If the diagnosis is carried out on time, it is possible to get rid of a simple sensor replacement.

It is not worth tightening with repair, because the oversaturated mixture does not affect the operation of the engine and significantly reduces its life.

Floating revs

In addition to slowly falling revolutions, car enthusiasts can push into such a phenomenon as floating momentum when they fall, and then increase sharply. The reason becomes an excessive supply of air into the system, which causes the engine to spin turns up to 2 thousand at idle.

This often occurs in cars having a fuel injection sensor. It calculates how much air is needed. When his work is broken, at different times a different amount of oxygen is supplied, as a result, rumble jumps are observed approximately every 3 seconds.

Faced with a similar phenomenon, a prerequisite will be all the same computer diagnostics. It is very important that her and all subsequent work carried out experienced, qualified specialists. Turning to a service that does not specialize in breakdowns of this kind can face the need to carry out an expensive engine overhaul before time.

Often, car owners are faced with such a malfunction when the engine is not falling when the engine is not falling, more precisely, they do not fall to the normal level of idling (XX). This applies to both the injector fuel supply system and carburetor.

Usually, idle speed of gasoline passenger cars, depending on the motor model, are within 650-1000 rpm. Any deviations from these indicators indicate the incorrect operation of the car supply system. With the elimination of this malfunction, it is not worth tightening, since the increased engine speed leads to an increase in fuel consumption in the car and accelerating the wear of the motor, which negatively affects the driver's financial condition.

Sometimes the reason can be wounded in excessive enrichment of the fuel and air mixture supplied to the cylinders. It provokes the growth of revolutions to some level, after which the engine begins to "chop up", thereby reducing the turnover to normal value, after which they rise again. This malfunction causes the "floating revolutions" effect, but the problem may be in other disorders of the power system. In addition, you should not forget that malfunctions in cases with injection and carburetor motors will be different.

Main engine malfunctions with carburetor power supply system

• The occurrence of the needle valve responsible for adjusting the gasoline level in the float chamber.
• The loose closure of the throttle is often happening when it is clogged or mechanically damage. The contaminated valve should be cleared with a special tool that can be purchased at the auto parts store. And with mechanical damage to this node, most often, the complete replacement of the carburetor is required.
• Incorrect adjustment of the XX system. This problem often appears after cleaning or replacing the carburetor. To eliminate, it is necessary to simply adjust it, providing the optimal ratio of gasoline and air in the fuel and air mixture.
• Stable high idling may indicate a loose closure of the throttle, located in the primary chamber. Such a problem appears due to the wear of the throttle damper cable or deformation of the damper itself.
• Damage to the intake manifold or wear of the gasket between the GBC or the carburetor.

In the case of an injection system, possible reasons for increasing idolotes are noticeably more. This is due to the fact that they can be associated both with the failure of mechanical components and a malfunction of electronic sensors.

Major malfunctions injector

• Fault Cooling fluid temperature sensor. Interruptions in the operation of this sensor lead to the fact that the motor constantly functions on elevated circulation, in warm-up mode. At the same time, after warming up the power unit to the operating temperature, the electronic control unit does not reset the revolutions to normal values, since the sensor signals that the engine has not yet warmed. The same happens with the improper functioning of the idle regulator.
• The throttle adjustment cable is hot. Especially often it happens on cars with great mileage.
• Disrupting the performance of the controller of the XX or its electronic sensor, while the turnover at idle can increase or disappear.
• Throttle position sensor fault.
• Scapping or excessive stretching of the return spring, which should return the flap in the original position.
• Violation of the integrity of gaskets, rubber seals injectors or the collector himself. With these problems, excess air from the environment falls into the combustion chamber.

The most banal cause is that when the gas is discharged, the engine revolutions do not fall to idle, there may be an inaccient placement of the rug under the accelerator pedal after visiting the car wash.

Let's summarize

First of all, the malfunction of the injection and carburetor system, you should begin to diagnose from inspection of the throttle.

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