Hello dear friends! While operating your car, almost every driver faces certain difficulties and problems. Someone , for others, antifreeze boils, and for others, the engine speed at idle does not drop at all. It is about the latter situation that we will talk with you today.
This is a widespread malfunction in which the engine constantly keeps revs. Leaving the engine at idle (XX), all the same, the tachometer needle does not want to go down.
Similar situations are found in almost everyone who has an injector and carburetor under the hood, diesel and gasoline ICE. At the same time, the reasons for injectors and carburetors are different. Let's take a closer look at them.
How to determine if there is a problem
First you need to understand how you can independently determine increased or simply abnormally high revs on your own car. After all, even at idle, there is a certain level of revolutions and it must be stably maintained.
In practice, identifying a problem that has suddenly appeared is quite simple. Even in those situations when a novice is driving, and he does not have much experience in such matters. First of all, you can just listen to the work of the internal combustion engine. The lower the speed of the motor, the quieter it will eventually run. But it's even easier to diagnose the problem with , which is installed on the vast majority of cars and trucks. Look at the position of the arrow and record exactly what speed you see when driving at a measured, calm pace, and what the device shows after warming up or when you release the gas.
Depending on the engine, for each power unit there are rules for idle speed. Usually it is from 650 to 950 rotations within a minute.
Now take a look at the instruction manual. There, the parameters of the norm for XX are necessarily indicated. If the current values differ from the indicators from the manual, this can be considered a deviation. That is, you need to start looking for a provoking factor.
Owners of injection engines are greatly helped by on-board electronics. If the revolutions on the twentieth turn out to be higher than the norm laid down by the manufacturer, on dashboard The check engine light will probably come on. Here I advise you to look into our material, where we talked about and their meaning.
Possible consequences
Similar phenomena occur on a large number of machines. Almost any modern and enough old motor able to present such a surprise to its owner. It could be:
- VAZ 2109;
- Renault Logan 1.4;
- VAZ 2107;
- VAZ 2110;
- Chevrolet Sense;
- Mitsubishi Lancer 9;
- Niva Chevrolet;
- VAZ 2114;
- Kia Cerato;
- Chevrolet Lacetti;
- Chevrolet Lanos;
- Toyota Corolla etc.
It would seem that, well, the speed has increased, but nothing terrible is happening.
In fact, processes can occur in the engine that are initially invisible to the driver. But gradually the consequences will become obvious and often frightening in their cost of restoration.
In no case should you leave an increase in speed at idle.
This can be explained by several main possible consequences.
Here are the potential problems:
- Fuel consumption will constantly increase, which will negatively affect your budget;
- A hot engine leads to problems with the cooling system and a general decrease in resource;
- Often the fuel will corny fly into the pipe, which also threatens to detonate it in the exhaust system;
- The total resource of the power unit will begin to decrease;
- The node with which the increase in speed is associated will suffer.
There are enough reasons to quickly take action and eliminate the provoking factor.
RPM drop on carbureted internal combustion engines
Despite the new environmental standards, in our country the number of cars with carburetor engines is quite impressive.
If you notice that on such an engine, the revolutions are kept at a fairly high level at idle, the reasons may lie in the following:
- Idling system incorrectly adjusted. If it has been interfered with recently, be sure to check the current setting;
- Problems with . An increase in idle speed may be due to its improper closing. Check the damper for soot. There may also be a chip or crack. There is only a replacement;
- Needle valve. The reason is its location. Perhaps when an incorrect dosage of fuel enters the chamber;
- Block head gasket. She just burned out. Will have to change;
- The suction is open. To check, you need to evaluate the operation of the damper in the primary chamber. If there is a problem, check the performance of the suction. Usually the problem is solved by lubricating the drive and cable.
It is these causes that most often appear on cars with carbureted engines, when the idle speed remains at an abnormally high level. They are potentially considered in situations where the engine almost immediately.
There is another option that is relevant for carburetor and injection ICEs. Here we are talking about sticking the gas pedal.
Problems on the injector
Separately, it is necessary to consider situations due to which at the twentieth revolutions can increase precisely on injection types of engines.
Unlike carburetor internal combustion engines, where all the problems lie in the mechanical part, the injector has a high probability of electronic malfunctions.
- Malfunction or failure of the sensor that controls the temperature of the coolant. This is a drive to constant operation in the engine warm-up mode. You need a diagnostic scanner and probably a replacement controller;
- Malfunction or breakdown of the XX sensor. It's a mass air flow sensor. Diagnostics with special equipment will help. Eliminate open wiring with a multimeter, replace the assembly as necessary;
- The same problems, but with the throttle position sensor. That is throttle. The controller either jammed or broke;
- Throttle return spring. It can stretch or come off, causing the corresponding behavior of the motor at idle. The node is returned to its place or changed to a new one;
- Hall throttle cable. Relevant for older cars. Replacing or lubricating will help solve the problem;
- Gaskets for injectors. They don't get damaged that often. Diagnosing the problem is difficult. They are usually checked last.
Be careful when running and observing the behavior of the tachometer in your car. If you see RPMs fluctuating, rising to abnormal levels, and behaving uncharacteristically, don't ignore these symptoms.
It is very important that the engine runs correctly in any mode, including idling. However, many car owners are faced with a problem: when the gas is released, the engine speed is not reset. As soon as such a defect is discovered, it is necessary to immediately find out the cause and eliminate the malfunction for the smooth operation of the car. Also, the engine can slow down for a long time, which also does not contribute to proper operation.
Usually, upon reaching operating temperature, the speed should drop to its norm. Indicators for each specific model vehicle the manufacturer specifies in the instruction manual. They may vary slightly depending on the mileage and the general condition of the car, but usually stay in the range of 650-1000 rpm.
In some cases, the speed drops very slowly or even stays at the same level of 1500-2000 rpm. In this mode, not only increases fuel consumption, which affects the finances of the driver, but also contributes to engine wear.
The reason for the failure in idle needs to be diagnosed with skilled craftsmen. However, to independently understand why the engine speed does not fall.
Malfunctions in the carburetor system
When releasing gas, the drop in speed can go badly on both injectors and carburetor systems.
If the car has a carburetor, then there may be several defects.
Most often, the speed is not reset due to a faulty throttle. When the engine warms up, it is in the open position to allow more air into the system. Then it closes and the speed should drop.
not completely closed throttle valve leads to the fact that when the operating temperature is reached, an over-rich mixture is still supplied, and the speed remains at the same level. If this part is heavily soiled or deformed, it cannot close completely.
You can clean the damper with a special tool, which can be purchased at an automotive supply store. Deformation may require replacement of the carburetor completely. The damper may not close tightly if the drive cable is worn out. Replacing it may improve the situation.
Another common reason why the engine speed does not drop at idle is a gasket between the carburetor and cylinder head that has become unusable, or a damaged intake manifold.
After replacing the carburetor or cleaning the power system, you can often notice that the engine speed drops slowly. This is due to improper adjustment of the idle system, often over-enriched air-fuel mixture. To fix the problem, it is necessary to adjust the ratio of the fuel and air supply to the system.
Also, a high level of fuel in the carburetor float chamber can provoke a defect in operation. The needle valve is responsible for it. Checking this detail may correct the situation.
Injector system
If an injection system is installed on the car, then the reasons high speed at idle can be much more. Here, both mechanical elements and electronic devices responsible for adjusting the twentieth can fail.
The main malfunctions of the injector include:
- Incorrect operation of the temperature sensor installed in the cooling system. Incorrectly received data from this device causes the electronics to recognize the engine as cold and work to warm up, thereby maintaining the high speed required to reach operating temperature. Overheating can often occur, which leads to more serious breakdowns, up to a major overhaul of the engine. The same effect is possible if the idle speed regulator does not work properly.
- The throttle control cable may be stuck. The higher the mileage of the car, the higher the risk of encountering a similar problem.
- The XX electronic work sensor often malfunctions, then the revolutions will either increase or disappear altogether.
- The spring that brings the throttle valve to its original closed position is not functioning properly, jumping off or stretching too much.
- Too much air enters the combustion chamber due to poor quality or leaky gaskets. It is necessary to carefully check the seals of the manifold and injectors.
- And the simplest reason is usually the wrong location of the mat after a visit to a car wash or dry cleaning of the interior. It is often inaccurately placed under the accelerator pedal, resulting in the appearance of improper engine operation.
If the car is oversaturated with a variety of electronics and all work is based on the correct functioning of the sensors, one of them may well become a problem. It will send incorrect data to the computer, as a result, the speed will not fall. Most likely, it will not be possible to detect the problem on your own.
It is necessary to contact a car service for computer diagnostics. Best of all, the task will be handled by specialists working at a service that specializes in repairing a particular brand of car. If the diagnosis is carried out on time, then it is quite possible to get off with a simple replacement of the sensor.
It is not worth delaying the repair, because a supersaturated mixture has a bad effect on the operation of the engine and significantly reduces its service life.
floating speed
In addition to slowly falling revs, motorists may encounter the phenomenon of floating revs, where they fall and then rise sharply. The reason is the excessive air supply to the system, which causes the engine to spin up to 2 thousand revolutions at idle.
This often happens in vehicles that have a fuel injection sensor. It calculates how much air the mixture needs. When its work is disrupted, a different amount of oxygen is supplied at different times, as a result, speed jumps are observed approximately every 3 seconds.
Faced with a similar phenomenon, the prerequisite will be the same computer diagnostics. It is very important that it and all subsequent work is carried out by experienced, qualified specialists. By contacting a service that does not specialize in breakdowns of this kind, you may be faced with the need to carry out an expensive overhaul engine ahead of time.
Often, car owners are faced with such a malfunction when, when the gas is released, the engine speed does not fall, more precisely, it does not drop to the normal idle level (XX). This applies to both the fuel injection system and the carburetor.
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 system. It is not worth delaying the elimination of this malfunction, since increased engine speeds lead to an increase in fuel consumption in the car and accelerated engine wear, which negatively affects the financial condition of the driver.
Sometimes the cause may lie in the excessive enrichment of the fuel-air mixture supplied to the cylinders. This provokes an increase in speed to a certain level, after which the engine begins to "choke", thereby reducing the speed to a normal value, after which they rise again. This malfunction causes the effect of "floating revolutions", but the problem may lie in other violations of the power system. In addition, do not forget that malfunctions in cases with injection and carburetor engines will be different.
The main engine problems with a carburetor power system
- The location of the needle valve responsible for adjusting the level of gasoline in the float chamber.
- Loose closing of the throttle valve, which often happens when it is clogged or mechanically damaged. Dirty damper should be cleaned special tool which can be purchased at an auto parts store. And in case of mechanical damage to this node, 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, providing the optimal ratio of gasoline and air in the fuel-air mixture.
- Consistently high idle may indicate a loose throttle valve located in the primary chamber. This problem appears due to wear of the throttle cable or deformation of the damper itself.
- Damage to the intake manifold or worn gasket between the cylinder head or carburetor.
In case of injection system food, possible causes 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
- Faulty coolant temperature sensor. Interruptions in the operation of this sensor lead to the fact that the motor constantly operates at high speeds, in warm-up mode. In this case, after warming up the power unit to operating temperature the electronic unit control does not reset the speed to normal values, since the sensor signals that the engine has not yet warmed up. The same thing happens when the idle speed controller does not work properly.
- Stuck throttle cable. This happens especially often on cars with high mileage.
- Violation of the operability of the XX regulator or its electronic sensor, while idle speed may increase or even disappear.
- 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 nozzles or the manifold itself. With these malfunctions, excess air from the environment enters the combustion chamber.
The most common reason that the engine speed does not drop to idle when you release the gas may be inaccurate placement of the mat under the accelerator pedal after visiting the car wash.
Summing up
First of all, a malfunction of the injection and carburetor power systems should be diagnosed by inspecting the throttle.
In the case of an injection engine, computer diagnostics will help to accurately determine the malfunction of a particular sensor. To do this, it is best to use the services of a service that specializes in servicing cars of a particular brand.
During the operation of the car, drivers have to deal with various problems. One of the faults, which is quite widespread, is the constant maintenance of high engine speeds. That is, even at idle, the engine speed does not fall. Such a problem can be observed both in injection and carburetor engines, but the reasons for this will be different. In 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 at idle speed of the car, the speed does not drop easily. This is easy to determine by ear, because, as you know, the lower the speed, 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 car, the rate of revolutions per minute at idle may vary. On average, it is generally accepted that the engine is running normally when the idle speed is between 650 and 950 per minute. If RPM is higher (unless otherwise stated in technical passport to the car), then this can be called a deviation.
Please note: On most fuel injected vehicles, the "Check Engine" light on the instrument panel will come on at high idle.
What causes high idle speeds
The first thing the driver should remember is the high fuel consumption at high speeds. Accordingly, if high speeds 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 fixed 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, you need to consider why a high idle problem can occur in such engines, since most of the problems overlap with injection engines. When such a malfunction occurs, pay attention to the following items:
Most of the problems that lead to high idle speeds in a carbureted engine are discussed above. Also, a common problem for carburetors and injectors cannot be ruled out - jamming the gas pedal.
Why the idle speed of the injection engine does not fall
Now consider the malfunctions that lead to increased idle speed in injection engine. Unlike carburetor engines, where all problems are mechanical in nature, a malfunction in an injector can be associated, among other things, with incorrect operation of the electronics. The main reasons are as follows:
As you can see, there are a lot of problems due to which 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.
Often drivers are interested in why the engine speed does not fall at idle. This situation is quite common, and neither carburetor engines nor more modern injectors are immune from this. True, the causes of 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 fixed 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 speed not drop at idle? To begin with, let's decide how to understand that a problem has arisen, and also see what it can lead to. Even an inexperienced motorist can determine the increase in idle speed. This is easy to hear. With an increase in speed, an increase in the noise of a running engine with the gas pedal released is observed. Also on machines equipped with a tachometer, you can trace the increase in speed on the device. On almost all models of passenger cars, idle speeds range from 650-950 rpm (check the indicator in the data sheet of your car), everything above is considered a deviation from the norm. Also on many injectors, this problem causes the inclusion of a “check” on the panel.
In any case, the problem should be fixed as soon as possible. Increased speed is the reason for the increase in fuel consumption. This increases the cost of refueling. Also, an increase in speed significantly accelerates engine wear. So it is not advisable to delay the solution of this problem. This way you save a lot of your financial resources. When identifying and eliminating the cause of high speeds, it should be remembered that on carburetors and injectors, the problem can be caused by various malfunctions.
carburetors
To begin with, let's deal with the problem on carbureted engines. This type of food is considered obsolete, but many cars on the roads are still equipped this way. Also, many motorists, for their own ideological reasons, use such motors, and are not going to refuse them. Diagnosing the source of the problem here is quite difficult, and this is given the small list of elements that cause an increase in speed. Let's look at what you should pay attention to:
- Seizure of the needle valve. In this case, the fuel enters the chamber is not metered. Moreover, depending on the location in which the valve is stuck, idle speed can both disappear and vice versa increase;
- Violation of the idle system adjustment. This usually happens after cleaning or repairing the carburetor. To avoid problems, you should correctly set the ratio of fuel and air supply. 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, it does not close due to the presence of soot on it. In this case, you will need to clean up this node. Usually, this helps. In some cases, the throttle valve may be damaged. Then you will need to change this part, but not all carburetors have this feature;
- Sometimes, the problem can manifest itself when, this happens quite rarely. But it's still better to check. To do this, with the engine running, open the radiator cap; if the gasket is burned out, White smoke. In this case, you will need to change the gasket;
- Open suction. Check how the damper works in the primary chamber. If a problem is identified, then it makes sense to see how the suction works. Most often, to fix the problem, it turns out to be enough to simply lubricate the cable and damper actuator.