Low idle speed on a warm engine: causes and solutions to the problem. Engine speed does not drop: why this happens Using ether to start the engine

Hello dear friends! Almost every driver encounters certain difficulties and problems while operating his car. Someone , for others, antifreeze is boiling, and for others, the engine speed at idle does not drop at all. It is about the last situation that we will talk with you today.

This is a widespread problem in which the engine keeps revving constantly. Leaving the motor at idle (XX), the tachometer needle still does not want to go down.

Similar situations occur in almost everyone who has an injector and a carburetor, diesel and gasoline internal combustion engines under the hood. That being said, 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 the increased or just abnormally high revs on your own car. Indeed, even at idle, there is a certain level of revolutions and it must be stably maintained.

In practice, it is quite easy to identify an abrupt problem. Even in those situations when a beginner is driving, he does not have much experience in such matters. The first step is to simply listen to the work of the internal combustion engine. The lower the engine speed, 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 note exactly what rpm 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, each power unit has its own idle speed. Usually this is from 650 to 950 rotations per minute.

Now take a look at the instruction manual. The parameters of the norm for XX are necessarily indicated there. If the current values \u200b\u200bdiffer 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 assisted by on-board electronics. If the speed at XX turns out to be higher than the manufacturer's standard, the check engine light on the dashboard will probably come on. Here I advise you to look into our material, where we talked about and their meaning.

Possible consequences

Similar phenomena are found on a large number of machines. Almost any modern and fairly old motor is able to present such a surprise to its owner. This could be:

• VAZ 2109;
• Renault Logan 1.4;
• VAZ 2107;
• VAZ 2110;
• Chevrolet Sens;
• Mitsubishi Lancer 9;
• Niva Chevrolet;
• VAZ 2114;
• Kia Cherato;
• Chevrolet Lacetti;
• Chevrolet Lanos;
• Toyota Corolla, etc.

It would seem that the turnover 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 daunting in their cost of recovery.

In no case should you leave the increase in idle speed.

This can be attributed to several major possible consequences.

Here we are talking about such potential problems:

• Fuel consumption will constantly increase, which will negatively affect your budget;
• A hot engine leads to problems with the cooling system and an overall decrease in resource;
• Often, the fuel will be corny to fly into the pipe, which also threatens its detonation in the exhaust system;
• The total resource of the power unit will begin to decrease;
• The knot with which the increase in speed is associated will suffer.

There are many reasons for promptly taking action and eliminating the provoking factor.

The drop in revolutions on carburetor 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 rpm is kept at a sufficiently high level at XX, the reasons may lie in the following:

• The idle system is incorrectly adjusted. If it has recently been tampered with, be sure to check the current setting;
• Problems with ... The increase in idle speed may be due to its incorrect closure. Check the valve for carbon deposits. Chipping or cracking is still possible. There is only a replacement;
• Needle valve. The reason is its occurrence. Perhaps, when an incorrect dosage of fuel enters the chamber;
• Head gasket. She is corny burned out. We'll 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 suction function. Usually the problem is solved by lubricating the drive and cable.

It is these reasons that most often manifest themselves on cars with carburetor engines, when idle speed remains at an abnormally high level. They are also potentially considered in situations where the engine almost immediately.

There is another option that is relevant for carburetor and injection internal combustion engines. Here we are talking about a sticking gas pedal.

Injector problems

Separately, it is necessary to consider situations due to which at XX the revolutions can increase precisely on injection types of engines.

Unlike carburetor ICEs, where the whole problem lies in the mechanical part, the injector has a high probability of having electronic faults.

• Malfunction or failure of the sensor that controls the temperature of the coolant. This is a drive for continuous operation in the internal combustion engine warm-up mode. We need a diagnostic scanner and probably a controller replacement;
• Malfunction or breakdown of the XX sensor. He is also a mass air flow sensor. Diagnostics with special equipment will help. Eliminate wire breakage with a multimeter, replace the assembly as necessary;
• The same problems, but with the throttle position sensor. That is the throttle valve. The controller is either jammed or broken;
• Damper return spring. It can stretch or fall off, causing the engine to behave at idle. The node is returned to its place or replaced with a new one;
• Hall throttle cable. Relevant for old cars. Replacing or lubricating will help solve the problem;
• Sealing gaskets on nozzles. They are damaged less often. It is difficult to diagnose the problem. They usually check it last.

Be careful when launching and observing the behavior of the tachometer in your car. If you see RPM float, rise to abnormal levels and behave abnormally, do not ignore these symptoms.

Many owners of injection vehicles could observe the effects when the idle speed (XX) suddenly drops in speed. This phenomenon occurs especially often when the motor is warmed up to operating temperatures. Sometimes the rpm drops so low that the engine stalls. Let's see what can provoke low idle speed on a warm engine, and also find out why they fall. This information will be useful to everyone.

The origins of unstable engine operation at XX

How will the picture be if the control unit does not receive data on the amount and volume of consumed air? So, for example, the reaction of the throttle valve sensor will be as follows - the speed will initially increase, but then the fuel mixture will start to get leaner, as a result of which low speed will be established on a hot engine. There is only one reason for this - the amount of air consumed by the motor has decreased.

However, the opposite also happens - the fuel mixture is enriched, and the engine starts to pick up speed again. Such cycles can alternate endlessly, these are floating revolutions. The problem of low idle speed on a warm engine in winter is especially urgent.

On some cars, events can develop in a different way - the revolutions grow, for example, up to 2000 rpm, and they remain so. The reason is that the injector is injecting more fuel. The amount of air does not grow, otherwise the engine would be able to raise the revs up to 3 thousand, however, then it would still start to stall.

Fuel quality

When the idle speed drops on a warm engine, you should not write off the fuel. It is possible that the problem is not related to the electronics, sensors, or actuators. Maybe the whole point is that the driver fills with lower-octane gasoline, and the ECU is designed for high-octane grades. Hence the lean mixture, so the control unit has no choice but to work like this.

Possible reasons

So what is causing this problem? One of the most vulnerable links in injection engines are sensors. One of the elements that directly affects engine performance and quality is the idle speed sensor. You can often find it near the throttle body. It is a taper locking needle stepper motor. When the throttle is closed, air enters bypassing the damper through the idle channel, which is blocked by the needle.

Another culprit behind very low idle rpm is Air, the second important fuel mixture after gasoline. Therefore, if the mixture is poor enough, then there is nowhere to take large turns.

When the system malfunctions, the ECU cannot correctly select and calculate the proportions of the fuel mixture in the XX mode. As a result, the engine operation will be unstable, the speed will begin to fall and rise.

A less common problem with low idle speed on a warm engine may be malfunctioning of the EGR system, or rather its valve. The element is installed in the intake manifold and its function is to discharge the exhaust gases. This is nothing more than Periodically, the sensor needs to be cleaned.

It will not be superfluous to also make sure that there is no air leak in the system and check the state of the throttle valve. Often the problem of low speed can be associated with a dirty damper or mechanical damage, deformation. It often happens that, for one reason or another, the damper gets jammed - hence another reason for low speed.

Why do sensors die?

Experts identify two reasons for low idle speed. One of them is associated with poor fuel quality. Often, a low octane number not only contaminates the working surface of the sensor very much, but can also cause various malfunctions in the operation of electronic units.

In addition, sensors often fail due to a banal marriage or exceeding the service life. Inexpensive sensors may well be of low quality or defective. This is why low idle speeds appear on cars.

How to eliminate air leaks?

In order to exclude or confirm the leakage of excess unaccounted air into the system, check the tightness of the air supply system.

To do this, you can remove the air pipe and blow into it from the compressor or pump. The hose can be placed in water. This will reveal cracks and other defects.

How to check the idle speed sensor?

It is recommended to use a multimeter to check if the sensor is working properly. The verification procedure is very simple. Replace the resistance between the contacts in the sensor block. It is important that the ignition is on. The resistance between different pairs of contacts should be between 39.5 and 81 ohms. If during measurements the multimeter gives different readings, then the sensor should be replaced.

Checking the mass air flow sensor

So, first, to check, turn on the ignition. You need to check the voltage with a multimeter. Measure it between the contacts with the green and yellow wires. On different cars, the voltage can vary from 0.9 to 1.2 V. You can determine the output of the mass air flow sensor out of order and by the appearance of the candles - black carbon deposits indicate that it is better to replace it.

How do I clean the idle speed control (IAC)?

When there is a problem with low idle speed with a warm engine, in some cases it can be corrected by flushing the DHX. To do this, de-energize the vehicle. The regulator is located on the throttle assembly, below the TPS (throttle position sensor). Prepare a clean rag, screwdriver, liquid in a spray can - this can be any carburetor or injector cleaner.

Cleaning begins with dismantling - to remove it, simply unscrew the fastening screws. Bolts are sometimes found. Once the sensor has been removed from its seat, the cleaning process can begin. The work is carried out using a rag treated with a liquid from a can.

It is also necessary to spray from a can on the needle. The latter on various car models can be both metal and plastic. The cleaner will not damage the plastic. But the liquid should not get under the spring. If this does happen, it is recommended that the sensor be blown out with compressed air as soon as possible. If this is not done, then the fluid will wash out the internal lubricant, which will cause the IAC to fail completely.

Conclusion

As you can see, only a few sensors can provoke low engine speed at idle. But even one small element can significantly ruin the life of the car owner, especially if the speed does not always fall. But this is not a problem, because this issue can be solved easily, without large investments.

Unstable idle speed or lack thereof is one of the most common engine problems that can be solved in a variety of ways.

Engine

One of the most common problems with a car's engine is erratic or no idle speed. Driving such a car becomes a real problem when driving in heavy city traffic. In addition to the fact that the driver can learn a lot of "flattering" about himself from other road users, he can create a real emergency.

The idle system is critical to engine performance from starting to power levels, which is why it is so important to pay attention to it.

The idle system is critical to the overall performance of the engine, from start to power, and therefore it is so important to pay attention to it. Experienced motorists know what can cause problems with the speed of carburetor and injection engines, and most importantly, how to "treat" these unpleasant automobile "diseases".

Idling system

The early releases had a dependent idle speed, and due to their design, they practically did not cause any problems with idle speed to their owners.

However, the times when a liter of gasoline cost 9 kopecks, and a bottle of mineral water - 10, are over, fuel economy has become relevant. It, in fact, contributed to the emergence of autonomous idling, introduced, mainly in order to reduce fuel consumption.

The advent of autonomous idling in the carburetor design increased the requirements for fuel cleanliness, and also complicated the maintenance of this device. Filters for fuel cleaning began to be introduced into the power supply system, since their absence began to directly affect the stable operation of the engine.

If on early carburetors it was enough to set the idle with a special screw at a certain angle, now everything is more complicated. Idling was separated into a separate system, with its own channels and nozzles responsible for supplying and metering fuel and air. In addition, an idle solenoid valve appeared, which works only when there is power on its winding.

The idle system has become more complicated, which has reduced its reliability, since now any speck or hair in the fuel can lead to interruptions in the operation of the engine or even to its complete stop.

A carburetor equipped with an idle solenoid valve is more economical in fuel consumption, but less reliable in terms of the stability of this idle speed. This is due to the fact that at any time the fuel jet located in the valve can become clogged, and the power supply to the solenoid valve can also be lost.

Unstable turnovers and reasons for their occurrence

Unstable engine rpm can be caused by sticking of the throttle valve, mainly due to its not returning to its original position. Most often, the reason lies in a faulty valve drive mechanics, or in a large amount of deposits on the inner walls of the lower part of the carburetor.

In this case, it is necessary to check the elements of the throttle valve drive and clean the throttle assembly. It is better to check the operation of the drive with an assistant: the assistant must smoothly press the gas pedal all the way, and the driver must follow the throttle actuator lever. The flap should take a vertical position and return without jamming to its original position. If the drive of the secondary chamber is mechanical, then at the end of the stroke of the damper of the first chamber, the damper of the secondary chamber should also open, and then also return to its original position.

When the assistant drowns the gas pedal to the end, you need to check the full travel of the throttle actuator lever, trying to squeeze the lever to the extreme position by hand. If the lever has a stroke, then it is necessary to achieve its full stroke from the gas pedal.

When an uneven stroke of the valves is observed (they close in jerks or do not fully return to their original position), the carburetor must be removed, disassembled and cleaned the throttle body.

If the car is operated mainly within the city, then the flap of the secondary chamber can generally be jammed, since, basically, traffic in the city is carried out on the first chamber. You shouldn't try to use force to develop it. For these purposes, there is a Carburetor Cleaner aerosol that does an excellent job of doing this.

With this tool, the throttle assembly on the injection motors is also cleaned. In addition, it can be used without disassembling the carburetor: with the air filter removed, it is necessary to inject a small dose of flushing into the primary chamber while simultaneously adding gas. The motor seems to "choke", dropping speed, and immediately responds with an increase. By repeating this procedure 2-3 times, you can be sure that the throttle assembly is flushed. However, in order to thoroughly "put things in order" in the valve body, it is still better to disassemble the carburetor and rinse it in detail.

Floating speed of the injection engine

Unstable idle speed in most cases is associated with contamination of the throttle assembly or extraneous air suction.

If the throttle assembly is dirty (when oil with dirt is visible during visual inspection), its channels are clogged and the bypass channel is not completely blocked by the idle speed regulator. The throttle assembly is removed and cleaned.

In case of extraneous air leakage, the mass air flow sensor gives incorrect data, which either adds or decreases the amount of fuel in order to equalize the mixture ratio. Turnovers, respectively, then fall, then rise. Leakage is detected by careful examination of the air supply channel.

Quick Start - Solution or Emergency?

An unstable engine start is associated with a malfunction of either the engine itself or its life support systems: the fuel and ignition systems (with a working battery and oil appropriate for the season).

Many people use the Quick Start tool to start the engine, but this is only a temporary solution to the problem. It can be used only in an emergency, when the delay is really like death, but at the first opportunity it is necessary to find and eliminate the cause of the unstable launch.

The "Quick Start" tool contains a large amount of highly flammable fractions and promotes quick engine start, which is especially effective at low temperatures.

Use the "Quick Start" tool as follows: without starting the engine, inject the compound into the intake manifold or the primary chamber of the carburetor, and then start the engine. Repeat the procedure if necessary.

Quick Start can also be used to diagnose the power system. When unstable revolutions are observed, interruptions in the operation of the engine, it is necessary to inject the composition into the intake manifold. If the engine is stable, there is a problem in the power supply system. When no changes are observed, either the ignition system or the gas distribution is faulty.

Using ether to start a motor

To start engines, starting fluid is also used - diethyl ether. Ether has high volatility and low flash point (mixed with air in a ratio of 2 to 48%).

However, ether is very insidious; if it is misused (or counterfeit ether), disastrous consequences for the engine are possible literally in the first seconds of launch. This is due to the fact that ether has a high combustion rate, creating enormous shock loads on all elements of the cylinder-piston group. Its combustion is sometimes accompanied by an explosive effect, which leads to instant damage to engine parts.

To prevent this, additional components are introduced into the starting ethereal liquid, which have lubricating, stabilizing and reducing the combustion rate and the temperature threshold of the mixture's autoignition.

If it happens in winter, it must be borne in mind that the engine must be prepared for winter operation. When the engine is started on summer oil in severe frost, the engine parts may simply "stick" to each other and simply break down after starting. In addition, summer oil will not be able to supply all rubbing vapors after starting, which will greatly increase their wear.

Starting with the use of an ethereal starting aerosol is best done with two people: one turns on the ignition, and the second injects into the intake manifold (moving the corrugation off the throttle) by pressing the spray gun 1-3 times, and only then starts. This will minimize shock loads when starting the motor.

Theoretically, the mixture is allowed to be injected into the cavity of the air filter, but since there have been cases of ignition, it is better to refrain from this method.

A serviceable and fully adjusted engine should start independently without using any starting mixtures at temperatures up to - 35 C. Priority should be given to its technical condition, and starting mixtures should be used only as a last resort.