Shakes the engine at idle. Vibration at idle: causes and consequences

The well-coordinated work of all systems and mechanisms of an automobile engine is the key to its longevity. The appearance of vibration processes in the motor indicates that a failure has occurred in its operation. Any vibration has a detrimental effect on the moving elements of the unit. It can also be transmitted to the body and interior, which is even worse. Therefore, if vibrations occur, it is worth identifying and fixing the problem as soon as possible. In this article, you will learn what causes vibration in the car at idle, and how to deal with it.

Main reasons

When thermal energy is converted into mechanical energy, which occurs in the power unit of a car, the occurrence of vibration is inevitable. Nevertheless, the driver and passengers do not feel it, thanks to the special design of the crank mechanism. Sometimes the engine starts to vibrate so strongly that it is even felt in the cabin. At idle, as a rule, this is most pronounced. Such a vibration indicates that something is wrong with the motor.

There are a lot of problems that cause vibration of the power unit. We will consider the most typical of them:

1. Valve timing failure.
2. Ignition system malfunctions.
3. Malfunctions of the power system.
4. Violation of the sealing of the vacuum brake booster.
5. Malfunctions of sensors for monitoring the ECU (electronic control unit) by the motor.
6. Engine mount failure.

Valve timing failure

If vibration occurs in the cabin at idle, the first thing to check is whether the marks on the camshaft star match the marks on the engine cover. If they do not match, then the valve timing has shifted. As a result, getting into the cylinders, the fuel mixture ignites unevenly. In addition, it may not have time to burn out completely. This leads to the fact that the engine loses power, starts to consume more fuel, smokes, and sometimes even stalls.

Label shifting occurs involuntarily. The main reasons for this are stretching of the timing belt, incorrect tension, incorrect marking during repairs. The same problem can also occur in a timing chain engine, such as in the Z22SE motor. Vibration in the cabin at idle in a car with this power plant occurs due to the unsuccessful design of the chain and oil nozzle in the timing drive. As a result of the hydraulic tensioner jamming, it ceases to perform its functions, and the chain begins to deform.

In a motor with a timing belt, the problem is solved by combining the above marks, which cannot be said about Z22SE engines. Vibration in the cabin at idle in such power plants is eliminated, as a rule, only by replacing the hydraulic tensioner, and sometimes the entire timing kit.

Ignition system problems

The main task of the ignition system is the timely ignition of the fuel mixture in the cylinders. When the electrical spark appears earlier or later than necessary, or is absent altogether, a failure occurs. It manifests itself in much the same way as in the previous case: the motor troit, stalls and vibrates.

The following problems may occur in the ignition system:

1. Malfunction of candles or increased gap between the electrodes.
2. Breakage of high voltage wire.
3. Malfunction of the ignition distributor (distributor).

Checking candles

It is better to start checking the system with candles. First of all, you need to start the engine and warm it up to operating temperature. Then you need to set the minimum idle speed (from 800 to 1000, depending on the type of engine). If the motor troit and vibrations appear, then you need to check the candles. This is done quite simply - you need to take turns removing the caps of the candles. If, when the cap is removed, the motor starts to vibrate even more or stalls altogether, this candle and its high-voltage wire are working. Having returned everything to its place, you need to check the rest of the candles. If, when the cap is removed, the engine operation mode remains unchanged, then the cylinder for which this candle is responsible does not work, that is, the fuel in it does not ignite.

To resolve this issue, you need to inspect the candle itself, its high-voltage wire and distributor. A common problem with spark plugs and wires is breakdown, in which part of the electricity simply goes to ground. This is usually accompanied by a subtle spark.

To check the health of the candle, you need:

1. Remove all caps.
2. Remove the broken spark plug.
3. Put a cap on it.
4. Place the spark plug on a surface that is in contact with the ground of the vehicle (such as a valve cover).
5. Ask an assistant to turn on the ignition and spin the starter idle.
6. Check for spark at the spark plug.

When the starter rotates, a stable bluish spark occurs between the electrodes of a working spark plug. If it is missing, or has a yellow tint, then the candle has become unusable. Checking the spark plug takes place only if the wire and distributor are known to be working.

If there is a vibration in the cabin at idle, it is advisable to check the serviceability of all candles. In addition to the integrity of the latter, it is important to pay attention to the presence of deposits and soot on their electrodes. They can also cause a weak spark. It is imperative to make sure that the gap between the electrodes of the candles is equal to the indicator provided by the machine manufacturer.

Checking the high voltage wire

The high voltage wire is checked with a multimeter. To do this, turn on the device in ohmmeter mode and set the measurement range to 20 kOhm. The wire should be disconnected from the cover of the distributor and remove the cap from it. The probes of the device must be connected to the two ends of the conductor that conducts current. If the wire is good, then the resistance is 3-10 kOhm, depending on its type. The difference in resistance of all high-voltage wires of the system should not exceed 4 kOhm. Owners of Renault cars often encounter oxidation of high voltage wires. Vibration in the cabin at idle, as a rule, disappears after replacing the wires.

Checking the distributor

Now let's talk about the ignition distributor. If there is any doubt about the serviceability of the distributor, first of all you need to check whether the wires are correctly connected to its cover. As a rule, there are numbers on the wires and the distributor that correspond to the cylinder number. If you confuse them, then vibration in the cabin at idle, tripling and other problems may occur. Oxidation of the distributor cover contacts also often leads to a similar effect. You can check their condition by a simple inspection. In parallel, it is worth paying attention to the integrity of the contact carbon located in the center of the cover. If it wears out, the power of the spark may decrease. The lid itself is also worth checking out. The fact is that it can break through, which leads to the loss of part of the current.

In addition to the above reasons, vibration can occur due to excessive load on the generator. This happens when the driver turns on many electrical appliances at the same time (stove, headlights, rear window heating, seat heating, and so on). When the load increases, the generator, which is designed to produce a certain amount of electric current, simply cannot cope with the task. As a result, the spark on the electrodes of the candles is defective.

Power system malfunctions

As the reviews show, vibration in the cabin at idle is often associated with a malfunction of the power system. All of them boil down to an uneven supply of fuel to the intake manifold, which leads to improper formation of the fuel mixture. In most cases, the vibration of the engine at idle appears due to the depletion of the mixture entering the cylinders.

It is possible to carry out an accurate diagnosis of this system only with the presence of special devices. This applies not only to carburetor, but also injection engines.

The main malfunctions of the fuel system, which lead to vibration processes in the engine:

1. Pump failure.
2. Clogged line and fuel filter.
3. Clogged jets (for carburetor engines) and a coarse filter.
4. Clogged nozzles (for injection engines).
5. Incorrect carburetor adjustment.

All this can lead to vibration in the cabin at idle. The causes of the malfunction should be sought in the fuel system only when there is 100% certainty that the ignition system is working. It is recommended to start checking with the fuel pump and line, and then proceed to the diagnosis of the carburetor or injectors.

Damage to the vacuum brake booster

As practice shows, not all car owners can associate the braking system with engine vibrations. In fact, brake failure often causes vibration processes. Before we learn how such a breakdown is diagnosed, let's deal with its origin.

The vacuum brake booster is connected to the engine intake manifold by means of a check valve and a hose. The last two elements are designed to create a vacuum in the amplifier. This is due to the discharge of air formed in the intake manifold during the movement of the pistons. Simply put, the check valve sucks air out of the amplifier. If the tightness of the valve or hose is broken, then more air enters the manifold than necessary. This results in a leaner fuel mixture.

Diagnostics of the vacuum brake booster

Checking the tightness of the system is quite simple. To begin with, with the engine off, you need to press the brake pedal 4-5 times with an interval of one second. At first it will fail, but after a few clicks it will stop. Then you need to press the pedal and, without releasing it, start the engine. When starting the engine, the brake should slowly move forward. If he did not do this, then there is an air leak in the system.

After making sure that vibrations arise precisely because of the brake booster, you need to inspect the air hose. To do this, it is recommended to remove it by loosening the clamps that fix it to the intake manifold and valve. The best way to check the integrity of the hose is by blowing. If the slightest air leak is detected, it must be replaced with a new one.

If everything is in order with the hose, then you need to check the check valve for proper operation by removing it from the vacuum booster housing. To do this, it is recommended to use a rubber pear, put on a fitting included in the vacuum cleaner housing. By pressing on it, you need to release air through the valve. If everything is in order with the valve, the air will freely exit and not flow back. In the absence of a pear, you can simply blow into a wide fitting, and then into a narrow one. In the first case, air should pass freely, and in the second case, it should not pass at all. If a defective check valve is found, it should be replaced.

Malfunctions of ECU control sensors

Due to the failure of one of the sensors responsible for giving signals to the electronic control unit, the motor may begin to work unstably. In the event of a breakdown of the lambda probe, fuel flow sensor, idle speed controller, throttle sensor and other elements, the computer operates in emergency mode, incorrectly forming the fuel mixture. To determine which of the sensors is broken, you need to read and decipher the error code, which is determined using the electronic controller.

Motor mount failure

Causes of vibration in the cabin at idle can relate to completely different parts of the engine compartment. Sometimes the problem lies in the motor suspension. As a rule, let down the front supports. Due to drying, subsidence, or even complete deformation of the pillows, the mass of the engine is distributed unevenly between the supports. Sometimes the reason lies in the weakening of the suspension mounts. Diagnosis of this problem is made by external inspection of the supports and checking the condition of their puffs.

Vibration in a diesel engine

As practice and owner reviews show, vibration in the cabin at idle can also occur on diesel cars. On the one hand, everything is much simpler here - no wires, candles or distributors. However, on the other hand, the vibration of a diesel engine is associated with more serious malfunctions. The first and most common of these is a breakdown of the high pressure fuel pump. It is possible to check its suitability for work only at a special stand, and not every auto mechanic will undertake to repair the unit. The second common problem is clogged fuel injectors. It is eliminated by cleaning on special equipment.

If a diesel car experiences vibrations in the cabin at idle, it is recommended to start the diagnosis by checking the compression in the cylinders. It is the key to the normal and stable operation of the power plant. Due to insufficient pressure in the cylinders, the fuel mixture either does not ignite at all, or does not completely burn out.

Among other things, when diagnosing a diesel engine in order to identify the causes of vibration, it does not hurt to check the marks on the engine cover and camshaft pulley. Often, the unstable operation of a diesel engine is associated precisely with the wrong injection angle.

Don't forget about the engine mount. As in the case of a gasoline power unit, due to stretched mounts and dry pillows, engine malfunctions can begin. By the way, under load they appear even stronger than at idle.

Conclusion

Today we have considered the main causes of vibration in the cabin at idle. Finally, it is worth noting that the car consists of a huge number of mechanisms, the failure of which can directly or indirectly affect the operation of the motor. Sometimes drivers, having double-checked the performance of all the systems discussed above, do not get rid of the problem. Especially often this happens with the owners of the Chevrolet Lacetti car. Vibration in the cabin at idle in this case is a more serious problem and requires the intervention of professionals.

We have already considered the reasons why the steering wheel vibrates, and today it is the turn to study the nature of the occurrence of other vibrations - from an idling engine. This phenomenon is unpleasant and threatening with serious problems for the car. Therefore, prompt diagnostics and elimination of vibrations of the power unit is in the interests of every owner who cares about his vehicle.

Causes of engine vibration at idle

During normal operation of the power unit at idle, there is nowhere for vibrations to come from: at this time, the torque from the motor is not transmitted through the gearbox to the cardan shaft and all serviceable transmission components should work without hesitation. If, at idle, the engine began to vibrate, then this is a direct sign of a malfunction that could occur for a number of reasons. Let's consider them in detail.

Reason #1. One or more engine cylinders are malfunctioning. This breakdown is known to many drivers - usually in such cases they say that the motor is troit. Recently, we detail why the engine troit and how to fix this problem. Therefore, we repeat here: the power unit can vibrate at idle constantly or periodically due to interruptions in the operation of one or several of its cylinders at once. There are several reasons for such a malfunction, we will list only the most common ones: a decrease in the level of compression in the cylinders, an excess or lack of air in the cylinders, too little or too much fuel entering the cylinder, and, finally, earlier or, conversely, later ignition of the air-fuel mixture in the combustion chamber . Each of these causes can lead to the appearance of engine vibrations at idle, which may increase or decrease, but not stop. From the motor, these vibrations are transmitted to the body, the steering wheel of the car, causing discomfort to the driver and passengers. If this problem is not corrected, the result can be disastrous - an engine overhaul will be needed.

Reason number 2. Loose power plant mounts. Another fairly common cause of vibrations when the engine is idling. We detail this malfunction in our article on the causes of vibrations on the steering wheel, so we will briefly outline this problem. As a rule, engine vibrations due to loose fasteners are most clearly diagnosed when the vehicle is stationary. At the beginning of the movement and a set of revolutions, the vibrations only increase. This problem most often occurs in cars with high mileage, in which, as a result of driving on roads with poor coverage, all the fastenings of the power unit become loose.

Reason number 3. Broken motor mount. Strong engine vibrations at idle can also occur for a more serious reason than described above. The vibrations of the power unit, in which a characteristic rattle of metal on metal is heard, indicates a breakdown of the engine mount - in the common people of the motor cushion.

There are four of them - front, rear, lower and upper, and any of them can break. The front motor mount most often fails, since it is on it that the greatest inertial and dynamic loads fall during the operation of the car. If one has burst, then, most likely, one more will order to live long (for example, front and back, upper and lower), so you need to carefully examine all the pillows.

Reason number 4. Different weight of parts of the cylinder-piston group. This is a less common, but sometimes occurring cause of engine vibrations at idle. The older the car (usually this phenomenon is typical for cars with a mileage of 200,000 km), the more significant the difference in the mass of the elements of the cylinder-piston group - the piston, oil scraper or compression rings, liners. During the operation of the car, these parts wear out unevenly, as a result of which vibrations occur in the CPG, which are diagnosed when the engine is idling.

Reason number 5. Incorrect installation of the crankshaft. This reason is from the category of those that arise due to the notorious human factor and are not directly related to malfunctions of the power unit. It happens that when replacing a worn crankshaft, the minder did not calibrate a part that, after installation, does not work correctly, causing strong engine vibrations at idle.

How to rid the engine of vibrations

Having decided on the reason why the power unit vibrates at idle, you can proceed to its “treatment”. Consider the options for repairing the motor in each individual case.

If the vibrations of the power plant occur because it is troiting, then this breakdown must be corrected depending on what is the reason for the failure of the cylinder. Having discovered that it has fallen, we can say that one of the elements of the cylinder-piston group has gone out of order. To understand which part is broken and does not allow the cylinder to work, you will have to disassemble the motor.

The cause of low compression may be a worn piston, piston rings or valves. In this case, only a complete replacement of the failed part will help (in no case do we recommend restoring these elements on your own, so that in the future you do not have to do more serious repairs to the motor).

The tripping of the motor and its vibrations, which arose due to the uneven entry of air into the combustion chamber, can be corrected by replacing the contaminated one by eliminating cracks in the line of the air supply system. Or - by replacing the failed throttle position sensors or mass air supply. If the engine troit due to increased or decreased fuel supply to the cylinder, then you will have to: a) inspect and then clean the injectors (if the problem is not solved after cleaning the injector, the injector will have to be replaced with a new one); b) inspect the operation of the fuel pump and replace it as an assembly; c) identify ECU errors and reset them.

The engine troit and vibrates at idle due to failures in the algorithm for igniting the air-fuel mixture? Perhaps the high-voltage wires are out of order. them to new ones.

If the fastenings of the power unit are loose, then we arm ourselves with keys with the heads corresponding to the bolts and stretch all the loose bolts. We replace the bursting engine mounts with new ones - you should not try to restore them, it will come out more expensive for yourself.

The reason for the vibration of the engine at idle was due to the different masses of the elements of the cylinder-piston group? The recipe is simple: to overcome motor vibrations, you need to replace worn parts with new ones.

If an incorrectly installed crankshaft is responsible for the occurrence of engine vibrations, then it should be dismantled, calibrated on special equipment and reinstalled. After carrying out this operation, the motor will almost certainly stop its “dances” and you will again be able to drive your car without experiencing vibrations that are acting on your nerves.

Always accompanied by vibrations. Normally, they are little noticeable to the driver, but sometimes the engine starts to vibrate and “twitch” very strongly, both while driving and at idle. Why is this happening, why is the vibration from the engine at idle transmitted to the body, and what to do about it?

Vibration at idle - causes

In idle mode, the engine runs, but does not transmit torque to the wheels of the car. The crankshaft rotates at a speed of approximately 750 to 950 revolutions, depending on the type of engine. The settings of the control unit maintain the idle speed at the level set by the manufacturer, since their “drawdown” will cause the engine to stall, and an increase will cause unreasonably high consumption of expensive fuel. In addition, the central piston group will experience high loads, which will reduce the engine life.

A serviceable and well-tuned motor runs, as a rule, quietly, the driver in the cab hears only a slight noise and can feel minimal vibration from the engine compartment. Some "jerking" may be normal after a cold start, especially during winter. But as the power unit warms up, when the parts expand from heat and take on standard dimensions, it should return to normal: therefore, it is important to warm up the engine in winter. In this case, there should be no failures in the operation of the engine, jerks, misfires, knocking and other extraneous sounds.

If the engine vibration appeared in motion or at idle, became noticeable and causes problems, up to the engine shutting down, it means that there are some problems with the unit itself or attachments that, in contact with the body, transmit vibration to it.

Important: vibration loads are extremely detrimental to the engine, their long-term influence can disable the unit. Therefore, the cause of vibrations must be identified and eliminated as soon as possible.

The main causes of engine vibration during idle operation:

• tripping of the motor;
• poor engine mount;
• failure of the pillows on which the power unit rests;
• unbalanced crankshaft.

Let's take a closer look at them.

Engine Trouble

By "triple" drivers mean a situation where the engine, according to the sensations, begins to "twitch", work unevenly. Strong engine vibration is audible and felt through the body, pedals and steering column.

The cause of tripling is the unstable operation of the cylinders, when, for example, one of them completely drops out of the ignition cycle. As a result, an imbalance occurs: the load on the crankshaft becomes uneven, and the built-in compensatory mechanisms are unable to dampen the engine vibration. Tripping is accompanied by a loss of power and increased fuel consumption.

The driver can partially compensate for the imbalance by accelerating by adding gas: the crankshaft will rotate faster, and this will partly remove the vibration. But power will still remain reduced, and fuel consumption will increase.

The vibration of the engine at idle and when driving at low speeds is felt most strongly when tripping: sometimes it may seem that the steering wheel is literally torn out of your hands.

The failure of one cylinder is a very serious problem, it requires prompt diagnosis and elimination. Increased vibration destroys the engine, in addition, the fuel that enters the cylinder, but does not burn out, washes away grease from its walls, increasing the wear of the cylinder mirror. And in older, worn out powertrains, fuel can leak through the seals into the crankcase, degrading the properties of the oil.

Troubleshooting can be done on your own. Vibration of the engine at low speeds, caused by the failure of the cylinder, as a rule, is accompanied by the activation of the Check Engine light on the dashboard, and the corresponding error code is written to the engine ECU.

Interesting: some experienced motorists can determine a non-working cylinder by ear, using a probe made from improvised means.

Possible causes of cylinder malfunction;

• Dirty or broken injectors (instead of spraying a fuel torch, they begin to “pour” and the mixture cannot ignite normally).

On the left - a serviceable nozzle, on the right - pouring:

• Malfunctions with the cylinder itself.
• Electrical and ignition problems (breakage of spark plugs, coils), etc.

Only qualified diagnostics can reveal the exact cause.

Vibrations after timing belt replacement

Strong vibration of engines at idle sometimes occurs after replacing the timing belt. If the procedure is carried out incorrectly and the belt is installed with an offset, this leads to a violation of the valve timing, failures and tripling. Therefore, when diagnosing, this unit should also be checked, especially if the timing belt has recently changed.

Problems with engine mounts and pillows

Defective engine mounts are a common cause of vibrations. Normally, the supports of the power unit take on the loads, so that the driver does not feel them. But pillows with fasteners, like other structural components, are subject to wear and tear, and over time may lose their functions.

Mitsubishi Delica cushions:

Important: the engine may begin to vibrate even after replacing the pillows with new ones, if the replacement parts have a greater rigidity than the old ones.

You can determine the wear of the pillows yourself, it is advisable to do it together. It is necessary to jerk the car back and forth with the hood open, and the assistant must fix the engine deflection angles during the rocking process. If everything is in order with the fasteners, the deviations in all directions will be uniform. If there is a difference between the angles, then the corresponding pillows need to be replaced.

Important: after replacement, the engine mount must be carefully adjusted.

Piston group and crankshaft imbalance

When repairing an engine associated with replacing or grinding the crankshaft, after performing manipulations, the shaft should be balanced. To do this, it is drilled in certain places in order to maintain the proper balance.

Also, after repair, it is necessary to weigh the pistons, fingers, and other elements of the CPG before assembling. If the balance is neglected, the difference in weight will lead to problems with vibration, which will be felt both “at idle” and when driving.

Other reasons

The above problems are far from the only ones that can cause engine vibration, which will be transmitted to the body. Possible alternatives include:

• Vibration is not the engine itself, but attachments and structural elements that are in contact with the body.

To identify the culprit of the problem, the car is driven onto a flyover, pit or lift, checking for possible sources of vibration in the engine compartment and outside it.

• Breakage of balance shafts, which are supplied with some engines to prevent vibration.

If the shafts are out of order, the motor will begin to vibrate strongly.

• Fuel system contamination.

Dirty nozzles have already been mentioned above - this is one of the possible reasons. Dirty injectors, fuel filter - all this can cause the engine to “tremble”. Similar symptoms are observed if water gets into the fuel: the motor vibrates, fuel consumption rises sharply with a parallel drop in power. Such a problem can be eliminated by pumping out the spoiled fuel from the tank, or by diluting it with high-quality gasoline / diesel fuel.

Be sure to check the condition of the air and fuel filters: the worse their throughput, the more unstable the engine will be, since the composition of the air-fuel mixture deteriorates.

• Malfunctions in the ignition system.

It is necessary to check the ignition coils, high-voltage armored wires, candles.

The appearance of such often leads to engine vibration at idle. If the car is standing with the engine running and the air conditioner/heater turned on, heated seats and windows, etc., the generator takes power from the engine more intensively, a vibration appears in the body. This is especially true for low-power power units of small cars. It is also impossible to exclude the malfunction of the generator itself, which should also be checked.

• Vibrations may not be related to the engine, but come, for example, from the gearbox.

Malfunctions of the "automatic" or "mechanics" can cause beats that give off into the body of the car, similar to vibration from the engine. Malfunctions can occur in the transmission itself and the clutch.

Important: engine vibration can sometimes be observed when the automatic transmission is engaged, especially in winter. This is due to the thickening of the oil in the box until the automatic transmission warms up, it is difficult for the motor to “drive” the oil through the assembly, and when the gear is engaged, speed drops and tripling may occur. You should also check the box filter. Similar symptoms can also appear with various malfunctions of the automatic transmission itself.

• Problems with the carburetor.

Incorrect carburetor setting will result in sub-optimal engine performance and potential vibration.

• Malfunction of the valve or idle speed sensor.
• Damage to the high pressure fuel pump in diesel cars.
• Throttle valve dirty.
• Poor quality fuel that detonates in cylinders instead of burning.

What to do if the engine vibrates

You can reduce engine vibration by carefully checking all the "weak points" that can cause vibration: the engine itself and its mounts, ignition system, fuel line, gasoline pump, injectors, electrical components, transmission, etc. Often the problem is solved by replacing the engine mounts. If the car is carbureted, then adjusting the carburetor will help get rid of the annoying “twitching”.

If the cause of the vibration is detonation, you should change the gas station and fill the tank with clean fuel only with the recommended octane rating.

Electronic diagnostics can be of great help, which will allow you to read the error code, if one is recorded in the memory of the engine ECU. In any case, if the engine starts to vibrate and the situation persists, you should contact a car service with qualified personnel in order to eliminate the malfunction as soon as possible.

It is important to remember: a long ride on a vibrating motor is fraught with an early failure and costly overhaul, so the problem should be diagnosed and removed as soon as possible.

Running an internal combustion engine with the clutch disengaged or in neutral gear is called idling. In this case, the torque of the power unit is not transmitted to the transmission of the car and then to the wheels. Over time, increased engine vibration at idle and low speeds may become noticeable. Depending on the type of internal combustion engine, the idle speed at which it functions stably is 850 rpm. A decrease in idle speed leads to unstable operation of the engine, including the possibility of a spontaneous stop.

Why engine vibrations appear at idle

Under normal operating conditions, the engine does not vibrate at idle. In this mode, no torque is transmitted through the gearbox to the driveshaft, so it should work stably and not create unnecessary vibrations. If the internal combustion engine has a strong vibration at idle or low speeds, make sure that the engine is the cause.

To do this, just depress the clutch pedal (to disconnect the motor from the gearbox). If the shaking remains when the clutch is turned off, this means that the problem lies in the engine, if not, then the result of twitching is problems in the clutch or gearbox.

During normal operation of the internal combustion engine, an imbalance is allowed, which does not greatly affect the comfort of driving a car. In winter, the engine may vibrate more when starting. However, when warmed up (after 5-10 minutes), the shaking level returns to normal. At the same time, jerks, dips and extraneous sounds during engine operation should be absent. If the nature of the jerking in the idle mode has changed, this indicates certain malfunctions in the internal combustion engine.

Increased vibrations arising from engine operation negatively affect both the condition of the internal combustion engine and the technical serviceability of other parts and elements of the vehicle. Therefore, it is necessary to diagnose the source of vibrations in a short time and eliminate it.

Auto mechanics identify the following main factors, due to which engine vibrations increase in XX mode:

1. Depreciation of the supports of the power unit.

2. Violation of the crankshaft balance, incl. after repair.

3. Engine tripping.

Cause #1 - Faulty engine mounts

These car parts perform two functions:

1. Attach the power plant to the body (frame) of the car;
2. They dampen his vibrations.

The supports are made of special rubber, which wears out during operation. Therefore, when cracks, tears, etc. appear. they cease to eliminate vibrations that are transmitted to the body and are well felt in the cabin. If only one damper has damage, then others are more likely to be worn out, but this has not yet manifested itself. In this regard, it is necessary to inspect and change all the supports.

Consider how to determine that the source of increased vibrations is a malfunction of the engine mounts.

1. Perform a visual inspection of the motor silent blocks. They should not have large cracks, tears and flake off metal parts.
2. Having installed a rolling jack with a rubber spacer, lift the engine one by one on each side where the pillow is located (the lifting point should be as close as possible to the support of the power unit). Observe engine operation after each change of jack location. When lifting the engine from the side of the faulty pillow, the force of vibrations transmitted to the car body will decrease.
3. In addition, diagnostics can be carried out without the use of a jack. This requires another person. We open the hood and rock the car, sharply changing the direction of movement. In this case, the assistant should look at the angle of roll of the motor in different directions. With serviceable pillows, the power plant will swing in all directions evenly and equally. The motor will roll more towards the faulty support, which needs to be replaced.

Reason #2 - Unbalance

If increased fluctuations appeared after the repair of the internal combustion engine, then there is a low quality of the restoration work carried out. During the factory assembly of the power plant or its repair at a high-quality car service with the dismantling of the crankshaft before installation, it is mandatory to balance the crankshaft assembly with the flywheel and clutch. Balancing work is carried out on a special balancing stand, where all beats are fixed and eliminated.

In general, the process is similar to the procedure for balancing wheels during tire fitting, with the difference that the specialist does not hang additional weights, but drills the necessary holes. When carrying out work in the "field conditions", balancing is not carried out and, as a result, the strength of vibrations increases. During the overhaul of the power plant, before assembly, it is necessary to carry out the weight distribution of the CPG parts. The uneven weight distribution of parts leads to increased twitching and a significant reduction in the life of the motor.

The tremor will certainly increase if the flywheel has repeatedly overheated and subsequently not been bored and balanced. But even with a strong reduction in the mass of the flywheel, its weight may be lower than the inertial one, smoothing out flaws in the balancing of the crankshaft and the difference in the weight of the CPG elements. As a result, unstable operation of the internal combustion engine at idle is observed.

Some car owners, in order to reduce the cost of repairs, remove the balance shafts. This inevitably leads to imbalance, increased vibration and load on the crankshaft, thereby reducing the life of the engine as a whole.

On vehicles with a manual gearbox, strong fluctuations at idle can be the result of a poor quality clutch.

Reason # 3 - Trouble in the engine

Triggering of an internal combustion engine is a process in which one or more cylinders do not work or function intermittently. Most often this is due to a failed spark plug. You can check this malfunction if you sharply press the accelerator lever. The consequence of the action will be a lumbago in the exhaust system.

It is difficult for inexperienced drivers to notice a faulty spark plug. This is due to the fact that the candle rarely fails at once. This process goes according to the following scheme: at first a good spark is formed, then it weakens over time, then gaps appear in spark formation and at the end the spark is not produced at all.

Over time, the problem intensifies, turning into strong vibrations that can even be given to the steering wheel and will be felt in the car. In addition, when tripling is observed:

• reduction of traction and power characteristics of the car;
• failures during acceleration;
• jerking of the car when driving uphill.

To determine a faulty spark plug, it is necessary to alternately remove high-voltage wires from the spark plug with the engine running. When you turn off the working spark plug, the engine suddenly loses speed and may stall. If the candle is not working, then when it is turned off, the nature of the operation of the power plant will not change.

Another way is to unscrew the candle from the block head and inspect it. It should not have cracks, soot, traces of oil and it should be dry. If the candle is not working, then the electrode is wet, as it will be washed by the fuel mixture, which does not ignite due to the lack of a spark.

Numerous and intermittent misfires indicate problems in several cylinders.

In addition to faulty spark plugs, engine tripping can also occur due to:

• interruptions in the supply of fuel;
• incorrectly set timing marks;
• low quality fuel mixture;
• valve burnout;
• malfunctions of high-voltage wires;
• ECU errors;
• ignition coil failure.

Video: Ford Focus 2 Flushing nozzles / Vibration at idle

For what reasons can the engine vibrate at idle

Consider the reasons when the engine is operating normally and the ICE cushions are working, but body vibrations are still felt.

1. The source can be both internal combustion engines and attachments or parts in contact with the body. Therefore, you need to study the engine compartment and carry out diagnostics from below. It will be more convenient for this to use a viewing hole, overpass or lift.
2. Malfunctioning balance shafts can also be the cause of increased vibrations. They are installed on some powerplants that are prone to high vibrations to reduce twitching and establish balance.
3. A common cause of vibrations is the poor quality of the fuel and the degree of contamination of the fuel system. Improper operation of the engine is manifested when water enters the gasoline. Such twitching is accompanied by a noticeable decrease in traction characteristics and an increase in fuel consumption. The problem is eliminated by cleaning the fuel system and completely replacing the fuel.
4. Contaminated air and fuel filters adversely affect the quality of the combustible mixture, which leads to improper mixture formation and unstable engine operation.
5. We check the serviceability of the elements of the ignition system (candles, wires, coil, including the lead angle).
6. The increased load on the car's generator causes an increase in the strength of the vibrations. For example, the simultaneous switching on of the heating of body and interior elements, air conditioning, etc. on vehicles with a low-power power unit leads to an increase in the strength of twitches. With an increase in engine speed, the vibrations decrease or disappear. In addition, jitter at idle can cause problems with an alternator that is not producing the amount of current it needs.
7. Significant vibrations that radiate to the body occur due to a gearbox malfunction, while the type of box (automatic, mechanical, robotic) does not matter. The reasons may lie in the transmission elements (clutch, driveshaft).

Vibrations in diesel engines

In addition to the main factors, the amplification of oscillations at idle in diesel units is due to malfunctions in other parts of the vehicle structure. The stable operation of these internal combustion engines strongly depends on the condition of the parts and assemblies of the fuel supply system, for example, on the degree of their contamination. Pollution occurs due to particles and impurities (including water) from the fuel and air into the fuel system elements due to poor filtration.

The culprit for the amplification of oscillations can be a malfunction of the nodes of the fuel supply system and, first of all, the high-pressure fuel pump.

If vibration is felt for the first time after starting a cold internal combustion engine, and disappear after warming up, then the glow plug is faulty. In addition, one should not exclude from the list of reasons the serviceability of the motor - the presence of a compression level that meets the standards.

Video: Vibration, another reason

Seal

In general, the vehicle engine is idling when the clutch is disengaged and/or the shift lever is in neutral. A serviceable motor when idling is almost silent and not subject to vibrations. The vibration of the engine at idle, which appeared during operation, indicates its malfunction and requires diagnostic work. Timely diagnostics will avoid the failure of the power unit and / or its costly repairs.

Causes of Vibration

There are a lot of reasons that can cause vibration of a running engine in general, and in idling mode in particular. This is due to the fact that a serviceable power unit is a complex, mechanically balanced design, and any malfunction immediately leads to an imbalance in the operation of its interconnected parts and assemblies.

The imbalance of the system causes a sufficiently strong vibration of the engine, which is instantly felt in the vehicle interior. At the same time, its presence can be detected on a stationary car by the following signs:

• items on the dashboard are able to move independently;
• the image in the rearview mirror is "blurred";
• when you touch the steering wheel, you can feel it trembling.

Among the causes of engine vibration at idle, the most common are:

1. Malfunction of one or more cylinders.
2. Violation of the integrity of the engine mounting parts.
3. The use of low-quality fuel, contamination of parts and components of the fuel system.
4. Wear of parts of the cylinder-piston group.
5. The consequences of poor-quality engine repair.

Ways to eliminate the causes of vibration

Feeling an unpleasant vibration emanating from under the bonnet space of the car, you should not immediately blame the power unit for this. It is necessary to carefully understand the reasons and find the only one due to which the engine vibration appeared.

• It is recommended to start the diagnosis by checking the engine mounting elements. The car engine vibrates slightly during operation, but this vibration should not be transmitted to the body. To do this, the engine is attached to the body with the help of special rubber-metal cushions. If at least one of them is damaged, then the itching instantly begins to be felt in the car.
• Having found a “killed” pillow, it is changed. If the cause lies in a faulty pillow, then the engine vibration at idle will disappear. According to car service specialists, 9 out of 10 calls about engine vibration at idle are connected precisely with “killed” pillows.

IMPORTANT! It is necessary to ensure that the motor is properly balanced after completion of work. Even a slight distortion of it will again cause vibration in the cabin.

Quite often, engine vibration at idle occurs due to uneven operation of the cylinders. This happens when one of the cylinders fails. The fuel in it does not burn out, the load on the crankshaft is distributed unevenly, and the engine begins to twitch from side to side.

In addition, the fuel entering the cylinder is mixed with engine oil and enters the crankcase. Oil diluted with fuel ceases to perform its functions, which ultimately leads to:

• mechanical damage to parts of the cylinder-piston group;
• violations of the lubrication regime of the remaining rubbing parts of the motor;
• overheating of the engine, since the oil also performs the function of a heat sink.

The presence of an idle cylinder is detected “by ear”, as the engine begins to “troit”. There are many reasons why one or two cylinders may not work. Most often they lie in system malfunctions:

• Ignition

• Fuel supply

Check the performance of: injectors; injector; fuel pump.

Attention: injectors are diagnosed and cleaned on a special stand.

• Gas distribution mechanism (GRM)

There are many reasons for off-mode operation of the timing: the drive belt is not installed correctly; elements of the drive belt tensioner are worn out; burnout of the cylinder head gasket; wear of the camshaft and / or hydraulic lifters.

If the check showed that all systems that ensure the normal operation of the power unit are functioning normally, they begin to search for a faulty cylinder. To do this, you need to measure the amount of compression in each of them.

The compression value in each cylinder of the power unit must comply with the standards specified in the technical documentation for the car. If in any cylinder there is a significant deviation from the standard value, then this indicates a malfunction in this particular cylinder.