Vibration in the blank: causes and methods of elimination

Idling is the work of the engine with the engine offclutch and installation of the transmission for neutral transmission. In this scenario, there is no transfer of torque from the engine to the propeller shaft, so the motor runs idle (hence the name). In this period of operation, the motor in service should not give any characteristic signs in the form of vibrations, claps and extraneous sounds. But if there is vibration at idle, then, in the engine, there have been changes that can significantly affect its performance from a not-so-good side. To avoid expensive repairs, do not delay this problem. And about why there is a strong vibration at idle and how to eliminate this problem, our today's article will tell.

What is the normal number of revolutions?

Depending on the type of motor in normal operationidling the number of revolutions of the crankshaft is from 800 to 1000 per minute. If the value is below this mark, the engine simply stalls. Well and in case of the raised turns idling the motor will absorb more fuel. At the same time, all the parts and components of the internal combustion engine suffer heavy loads, and accordingly their service life decreases.

vibration at idling speed


Why there is vibration at idle? Most often this is due to the following reasons:

  • Engine Trouble. In this case, one of the engine cylinders may not work.
  • Incorrectly fixed motor.
  • Other factors. We'll talk about them a little later.


So, the first reason provoking vibrationsmotor. Engine throttling is the most likely cause of unstable engine operation, since with a non-working cylinder, there is a significant imbalance and an incorrect load distribution on the crankshaft. As a consequence, you can observe how the motor jerks from side to side. Also, during the movement, the vibration of the rudder is noticeably felt. At idle, all these signs are more noticeable. The more the shaft rotates, the less strange vibration will be felt. But at the same time you will notice how the car began to absorb more fuel and noticeably lose power, especially when driving "downhill."

The solution in this situation is only one thing - urgentlyrepair a non-working cylinder. If this is not done on time, the coking of the parts of the CC will soon occur. At the same time, their service life will noticeably decrease, since the fuel does not burn in the chamber, but only flushes the lubricant.

Incorrectly attached motor

This is also one of the common reasons why there is vibration on the body at idle. Most often, this problem is associated with the wear of one of the cushions on which the engine is attached.

vibration on idle
Also vibration on the body at idleis due to the use of too rigid fastening elements. But wherever this problem is hidden, it must be definitely solved. Of course, an improperly fixed engine is not as bad as an inoperative cylinder in it. However, in order to avoid constant shaking and sound, you need to change the supports or adjust their position in the right direction.

How to find out the disadvantages of the engine mount? It's very easy to do this. To do this, you need to open the hood and call an assistant to alternately turn on the "neutral", the rear and the front gear. And at this time you should pay attention to the position of the engine on the supports. Thus, you alternately unload the cushions that hold the motor. With each new gear change, the engine will swing in different directions at the same angles. If in any of the sides he deviated more than usual, then in this place you need to replace the pillow.

Other factors

In addition to the idle cylinder and wrongfixed engine, vibration at idle speed can be triggered by a number of other factors. Of course, they are much rarer, but still they can not be considered as an option.

vibration of the rudder on idle

First of all it is necessary to note the elementsfuel system. If they are heavily soiled, the fuel-air mixture will not burn out sufficiently. Because of this, there is an increased expense, strange sounds (perhaps even claps) and vibration. Even worse, if the water gets into the gasoline. In this case, in addition to a large expenditure of fuel, there is a risk of coking of the cylinders. As a result, the engine is not working properly. Sometimes engine oil and soot can penetrate into the fuel system, which also has a negative effect on the engine operation cycles.

The second reason is the different weight of the partscylinder-piston group. The operation of the car, especially if its mileage is more than 200 thousand kilometers, requires increased attention to the engine, and sometimes replacement of parts in it. Even a small difference in weight can significantly affect the engine performance in the future. And it concerns all the details of the engine, be it the piston, connecting rod or skirt.

body vibration on idle

On some small cars with an electronic systemcontrol of the damper, the vibration of the passenger compartment at idle turns may occur due to the increased load on the generator. Especially often this happens in the winter, when the car at the same time working lights, stove, heated glass, seats and mirrors. Often on such auto vibration occurs at the time of the stop. When the driver releases the accelerator pedal, the onboard computer sends a signal to close the flap to idle, and the motor loads from the generator - it is at this point that there is a strong shaking of the motor. As a rule, it disappears in 3-5 seconds. Such idling vibration for small cars, especially with automatic transmission, is considered normal, and in most cases it is solved using a better fuel and replacing the air filter.

It is worth noting that the shaking of the motor may occur when the toothed belt is replaced, especially when the pinion of the balancer shaft rotates together with the removed part.

car operation
After the shift, it is unlikely to fall on its ownformer place. Therefore, when replacing the belt, do not rotate the pinion of the shaft with your fingers, unless you want to evaluate the condition of the bearings. But here you also need to be very careful and accurate. Any displacement of the part can be fraught with vibration, creating a constant discomfort for you and your passengers.

Crankshaft balancing

It also happens that the vibration at idleappears after replacing the crankshaft. The fact is that this element, like a conventional wheel, must undergo a calibration procedure before installation. It is balanced on a special stand with a flywheel and a clutch basket. In this case, the master drills the excess from its surface. If this procedure was not carried out and the crankshaft was installed without preliminary calibration, wait for a strong shaking.

What are the consequences of low idling?

Movement and operation of the engine at excessively low rpm, especially when trying to accelerate, can lead to rapid wear of the following elements:

  • Pistons of the engine (thus the block of cylinders is destroyed).
  • Inserts of a cranked shaft.
  • Clutch baskets.
  • Flywheel.
  • Transmission bearings.
  • Chains of gas-distributing mechanism. At low shaft speeds, it simply stretches.
  • Cylinder liners. Because of the deposit, their walls are damaged.

idling speed

Thus, with constant vibrationthere is a rapid wear of engine parts. At the same time, its promotion is much slower, and the crankshaft packing is greatly destroyed. As a consequence, there is a risk of oil leakage.

Intentional understatement of revolutions

Some motorists deliberately do so,so that the idle speed was below normal. This is often done to save fuel. However, as practice has shown, such a decision is not very correct. It should be remembered that repair and replacement of worn engine parts can be more expensive, and dozens of times. Therefore, do not deliberately underestimate the engine speed, thinking that it will save your wallet.

How to adjust the engine?

So, we had a vibration on the idleturns. What can be regulated here? To do this, it is necessary to pay attention to several units and units that are part of the fuel system. Depending on the type of car power it can be a carburettor, an injector, as well as a mass of various electronic and mechanical sensors, the number of which on modern cars varies already by tens. In addition to these elements, the fuel pump is also regulated.

When adjusting, it must be remembered that the numberrevolutions directly depends on the degree of compression of the throttle valve, which regulates the supply of air to the cylinder, as well as from the operation of the idler valve, which supplies oxygen regardless of the first part. Increase this value with the accelerator pedal. So you can align the idle speed to 800-1000 rpm.

How to save a resource of engine parts in different operating modes?

In order to prolong the life of the engine, you do not needonly follow the normal number of rotations of the crankshaft. Will also be able to properly operate the car, choosing the optimal range of work. Experts recommend a shift to higher gear in the speed range between peak torque and maximum power. At the same time, during the movement under high load (for example, when driving on a hill), it is not necessary to allow the shaft rotation moment to fall to values ​​close to the idling speed.

vibration at idle
Once you feel the characteristic vibrationoverloaded engine, immediately switch to a lower gear. Otherwise, the motor parts will be subjected to high loads. This can provoke the failure of the entire cylinder-piston group. Remember that high speed for the engine (especially the petrol) is not as bad as low. If you have a gasoline car, change your driving style so that the engine speed does not go down to 2 thousand and below. In this case, the crankshaft can be untwisted to 6000-8000 rpm. As soon as you feel that your car has stopped pulling and is about to end, switch to a lower gear and in any case, do not allow the engine to slow down until vibration, especially if you go downhill. Operation of the car in this mode will save the parts from premature wear. At the same time, this "high turnover" driving style is not displayed in any way at higher fuel consumption.


So, we found out why there is a vibration onidle turns, than it can be caused and how to eliminate it. Thus, fighting engine shaking plays a crucial role in ensuring the safe, reliable and durable operation of the car over hundreds of thousands of kilometers. Any vibration, including idling, is very harmful to the car. It not only delivers unpleasant feelings to you and your passengers, but also greatly damages the engine. The situation can go right up to unauthorized unscrewing of bolts and nuts. Already these failures can lead to the most unpredictable consequences.

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