Engine vibration at idle speed: reasons why it appeared, what if it is transmitted to the body

The engine vibrates strongly at idle: possible reasons

The normal operation of a serviceable motor requires minimal vibration, which is quite acceptable. It should also be taken into account that in the cold season the engine may vibrate somewhat more strongly. After 3-5 minutes of warming up, the vibration level should return to normal. In parallel with this, there should be no jerks, dips or omissions, as well as extraneous sounds in the engine operation.

The appearance of noticeable vibrations indicates that certain malfunctions are possible. Let us immediately note that increased vibrations are detrimental to the internal combustion engine, so such a problem must be diagnosed and eliminated as quickly as possible.

Among the main reasons why the engine begins to vibrate (shudder, twitch) at idle, experts identify the following:

• engine troits;
• problems with the correct mounting of the motor;
• faulty engine mounts;
• crankshaft imbalance;

For normal operation of the power unit, idle speed is usually around 750-950 rpm, which depends on the type of engine. Reducing the idle speed will cause the engine in this mode to start running less stable and may even stall at idle. An increase in speed naturally leads to increased fuel consumption, as well as an increased load on the CPG and other components of the internal combustion engine. As a result, motor life is reduced. For this reason, an optimal balance is maintained for each engine to achieve maximum efficiency and stability at idle.

Motor troits

If the engine starts to stall, then uneven operation of the cylinders is observed. The most severe engine vibration at idle is felt if one of the cylinders is not working. Pressing the gas pedal allows you to partially compensate for the resulting imbalance by increasing the crankshaft speed, but engine power will still be reduced.

The load on the crankshaft when the cylinder is not working or is misfiring remains uneven, which causes jerking and jerking of the engine. The driver usually feels a noticeable shudder and vibration in the steering wheel, which can also be transmitted to the body. The engine vibrates most strongly at idle, and also under load when driving at low speeds.

It is necessary to eliminate the problem with an inoperative cylinder as quickly as possible, since in addition to vibrations that destroy the engine, normal fuel combustion does not occur in the combustion chamber of the problem cylinder. As a result, excess fuel washes away the lubricant from the walls of the faulty cylinder, thereby increasing wear on its mirror. Also, on worn-out engines, there is a high probability of unburned fuel leaking through the seals, which leads to fuel getting into the engine oil and losing its beneficial properties. In this case, the engine wears out faster, cokes more, etc.

Additionally, it is worth noting the engine vibrations that appeared after replacing the timing belt. In this case, it is necessary to eliminate the possibility of an error when installing the belt, since a displacement of even one tooth leads to a violation of the valve timing. The result is engine malfunctions and engine tripping.

Mounting and malfunction of engine mounts

A common problem that causes increased engine vibrations is a defect in the power unit mounts. Most often, the problem lies in the engine supports (so-called mounts), which can become unusable over time. These pillows are a kind of dampers that not only hold the internal combustion engine, but also dampen vibrations.

Also, an increase in the level of vibrations can occur after replacing one or more pillows with products with greater rigidity.

You can diagnose the problem as follows. Invite an assistant and open the hood, then rock the car with sharp jerks by moving the car forward and backward. The assistant must record the angle and degree of engine deflection during such rocking. Normally, the engine should swing forward, backward, and also to the sides evenly and equally.

If deviations are detected, that is, the motor has a greater tilt in one direction, the corresponding motor mount will need to be replaced. Please note that experts recommend replacing engine mounts even if there are no visible defects or damage on the part itself. Also, after replacing the support, it is necessary to carefully adjust.

Balancing the crankshaft and CPG

During the process of repairing an internal combustion engine, which involves grinding or replacing the crankshaft, it is necessary to subsequently balance the part with the flywheel and clutch. To balance the crankshaft, specialists drill out extra grams in its body. It is also necessary to weigh the pistons, piston pins and other parts of the CPG before assembling the engine. Differences in the weight of parts can cause a serious increase in vibrations.

How to find the reason

How to find the source of vibration without specialized tools? Without special equipment at hand, it is impossible to determine the excess level of body vibrations. In addition, each car owner perceives this subjectively - for one driver, vibrations and knocking when accelerating the car are commonplace. For another driver, even a rustle can be a reason to panic.

However, shaking is considered unacceptable in the following cases:

• When objects lying on the dashboard begin to move on their own;
• When a strong vibration of the steering wheel is felt (radiating in the palm of your hand);
• When steering wheel wobble or body vibration occurs, the cause of the problem is often an imbalance of the front wheels;
• When the reflection in the salon mirror begins to blur;
• If vibration is felt in the floor or controls, especially at low engine speeds;

First, you should remember that shaking can occur due to uneven operation of the motor. Perhaps just recently you went to a service station to repair your engine (for example, replacing the crankshaft). In this case, it is likely that the new crankshaft has not been balanced with the flywheel. In addition, increased vibrations on the body arise from improper adjustment of the carburetor or throttle valve. In this case, the mixture does not burn completely, and the engine idle speed is below 800 rpm.

The first step is to inspect the condition of the engine mounts, gearbox, intake and exhaust systems and the parts located near them. Perform diagnostics first with the engine turned off, then with the engine running. Engine supports (mounts) must always be solid. If a crack appears or the pillow shrinks, the pillow is replaced. The vibration in the body should disappear after replacing the pillow yourself. The engine protection can sometimes be very close to the sump - when there is a small gap between the protection and the sump, most likely, vibration and knocking occur due to their contact.

Then you need to check the quality of tightening of threaded connections, motor mounting and other components. If you find a loose bolt, you will need to tighten it to the required level. There are cases when vibrations appear due to the impeller of the fan cooling the radiator. In this case, remove the impeller and listen to the operation of the motor without it. Then you need to turn off the attachments one by one (removing the drive belts) and check the level of engine vibration after starting and when operating in different modes.

It may be necessary to balance the pulley or replace the belt. Sometimes the cause of shaking is the clutch basket with the flywheel. To calculate them, you need to press the clutch pedal to the floor, start the engine in gear, and after a couple of seconds turn on neutral, then remove your foot from the pedal. If the shaking continues, it means that it is due to the flywheel or basket. An imbalance of the cylinder-piston group is possible, especially if one or two pistons or one or two connecting rods have been changed.

The instructions say that if the body vibrates after 80 kilometers per hour, it most often occurs due to elements of the transmission or chassis of the car.

When the vibration of the engine changes with the speed of the vehicle, most likely, one of the units behind the transmission driven shaft vibrates. These are cardan or drive shafts, transfer case parts (if your car has one), wheels or hubs. By the way, when body vibration occurs during braking, the cost of the issue is your life! The problem lies in the brake discs or drums. Your safety depends on the proper operation of the brakes, so you cannot delay repairs. Such vibrations are especially noticeable on the steering wheel.

Another reason for shaking may be poor-quality tire rubber. Its composition can be very rigid, because of this, the load on the front wheels increases when the vehicle speed decreases. Vibration of the car at a speed of only 10-15 kilometers per hour indicates an imbalance of the wheels. As a rule, a similar problem occurs after changing the car's shoes to winter tires. Eliminated by wheel balancing. If the wheels are front, it may manifest itself in the form of steering wheel beating.

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To check whether the wheels are to blame for vibration during acceleration, you need to swap the front and rear. However, it is best to diagnose the car, then its elements will be checked on the stand and the cause will be reliably identified. Disc imbalance is solved by hanging weights. The weight of weights can reach from 5 grams to 100 grams. After proper balancing with weights, vibration will disappear during acceleration. It is best to do the balancing at a tire shop; the owner himself cannot handle it.

Vibration after a major overhaul is caused by an imbalance of the cylinder-piston group, its incorrect assembly or deformation of parts. Pistons and connecting rods are always selected based on weight. The difference in weight should not be more than 5-10 grams.

Attention: The pistons must also be of the same diameter, otherwise there will be a difference in the compression of the cylinders, hence vibrations and damage to parts.

Another common cause of vibration is the driveshaft:

The driveshaft is a common cause of body vibrations

To fix this problem, you need to remove the shaft. Then perform the steps in the following order:

• It is necessary to check the condition of the crosses at the ends of this shaft;
• Check that each crosspiece moves freely in any direction when you press it without force;
• If it is necessary to apply force, or in some direction the cross does not move at all, then it needs to be replaced;
• If it is necessary to replace the crosspieces, at the same time you need to check the presence of grease in the caps for the roller bearings;
• Having completed checking the crosspieces, you can proceed to checking the spline joint of the cardan;
• To do this, you need to simultaneously rotate parts of the cardan around the axis;
• In this case, the free play should not exceed 1 millimeter;
• When the spline part is damaged, then the cardan must be replaced;

Another reason for vibrations in the body when idling is improper fastening of the transfer case; you need to adjust it. If you don't have one, you can skip this point. It is necessary to lift the car with a jack or lift. The wheels should not come into contact with the ground during work. In addition, it is necessary to ensure free access to any transfer case mounts.

You start by inspecting the condition of the fasteners. They are usually not very durable since they are made of aluminum alloy. When inspecting, pay attention to cracks and chips on them. If there is a need to replace the old mount with a new one, then a gasket must be laid between the mount and the body, which is best made from a conveyor belt. When removing the transfer case, special attention should be paid to the intermediate shaft located between the gearbox and the transfer case. After performing the checks we described, the transfer case should be returned to its place. First, it is hung on the fasteners, but do not tighten the nuts completely. Then you need to ask an assistant to accelerate the car to 80 km/h. Only then can the nuts be tightened completely.

Engine vibration at idle speed: main causes and solutions

One of the reasons for incorrect engine operation, leading to significant and expensive car repairs, is strong engine vibration at idle.

Timely diagnostics and subsequent measures taken to eliminate vibration can fully insure the car owner against many troubles, including not only the comfort and safety of car operation, but also significant financial investments in major repairs.

The operation of a serviceable engine implies the presence of minimal vibrations. When the air temperature drops, the motor may vibrate slightly more. However, after five minutes of operation, these fluctuations should disappear completely.

The appearance of fairly noticeable vibrations, skips, jerks, dips and/or extraneous sounds during engine operation indicates that the vibration mode is disturbed due to the occurrence of situations of a certain nature.

Motor troits

Perhaps the main cause of vibration can be called engine tripping. In this case, in addition to the fact that the engine shakes at idle, a number of other problems may occur. This is, first of all, excessive fuel consumption, loss of car power, as well as problems with starting.

In essence, tripling is a failure (malfunction) of one or more cylinders. This situation may arise due to problems with the spark plugs, the air filter not being changed in time, a leak in the intake valve area, or due to a broken high-voltage wire.

Troubling is a rather dangerous problem, which can be followed by other breakdowns if you do not intervene in time. It is not so much the vibration of the engine at idle that is harmful, but the increased load on the crankshaft and the entire engine as a whole.

If the car does not drive well even on small hills, consumes more fuel than usual, and the idle speed begins to float - most likely the reason lies in poorly functioning cylinders. The first place to start checking is to inspect the spark plugs.

Most likely, replacing them will significantly improve engine performance. If you don’t have new candles at hand, it doesn’t matter. You can try to revive already installed ones. To do this, you need to clean them from carbon deposits (a metal brush is suitable for this).

If replacing the spark plugs does not help, you should check the integrity of the wires going to them.

Basically, engine tripping occurs on used cars (often it is not known at all whether the previous owner monitored the technical condition of the car). In this case, it is advisable to immediately replace the spark plugs, without waiting for malfunctions in their operation to appear. And if you have the means and desire, you can also buy new wires.

Speed

This is 800-1000 rpm. If the number of crankshaft revolutions is lower, the engine will begin to stall; with a higher number, fuel consumption will increase and engine parts will wear out faster. It is worth noting here that in the cold season, slight vibration after start is a normal phenomenon, which disappears after 5 minutes as the power plant warms up. If the engine shaking does not disappear, it is necessary to consider the reasons for its occurrence.

Saving engine life

Remember: low speeds are more dangerous to a car engine than high speeds. Reducing the idle speed will lead to unstable operation of the unit and a rapid reduction in engine life .

If you are the owner of a car with a gasoline engine, try not to allow a further decrease in the speed already at around 2000 rpm. If the engine “does not pull”, for example, when trying to drive on hills, it is enough to switch to a lower gear. The appearance of vibrations is a very bad signal.

Also, do not forget that the service life of the engine and its adjacent components can be affected by seemingly unimportant details. For example, internal combustion engine airbags . Often they try to save money on replacing them by purchasing inexpensive analogues from Asian companies. Good and relatively inexpensive options can be found under the brand names Impergom, Boge, Lemfoerder, Ruville, Hans Pries (pay attention to the article number - the last symbols indicate the quality standard of the product). The same can be said about the choice of sensors, timing belts and fuel pumps - you should not skimp on them.

Engine mounting

Strong vibration of the engine at idle speed can be caused by poor fastening of the power plant to the body. In some cases, it is possible to identify breakdowns of the protective cushion through which the motor is attached. It is advisable to carry out diagnostics together with an assistant, who will sequentially switch gears in the gearbox. An observer looking under the hood will identify which gears are causing problems.

Even after replacing the airbags, the shaking does not always leave the car. This is due to the need to properly configure and adjust the fasteners.

Failure can occur for any of the four supports (rear, front, bottom or top). However, practice shows that the most vulnerable is the front support. It is subject to increased static and dynamic load. As soon as one of the pillows breaks, then if no measures are taken, the rest will quickly break .

For novice drivers, vibration in the steering wheel at idle is not always obvious, so we recommend periodically undergoing diagnostics in specialized workshops or from experienced technicians. Otherwise, trouble cannot be avoided. If you decide to look for the cause yourself, then you need to use the method of exceptions, moving from simple to complex causes.

Problems with motor mounting

Another fairly common reason why the engine jerks at idle is its improper mounting (or a malfunction of one of the protective cushions). Usually, vibration in this case reverberates throughout the body.

It is quite simple to make sure that the problem lies here. True, for this you will need the help of a partner, who will alternately shift gears: neutral, reverse and forward. At this time, you need to open the hood and look at the engine deflection.

If the mount is installed correctly and the protective pads are not worn out, then the engine will tilt at the same angle each time. In this case, the supports themselves will be unloaded one by one. If the deviation in any direction greatly exceeds the norm, then the problem is in the mounting (the engine shakes). In this case, you will most likely have to replace the pillow.

Balancing the cylinder-piston group and crankshaft

Often, during repair work on a power unit, it is necessary to grind the crankshaft or replace it. This leads to weight changes. It usually becomes higher than with the old part. So that after this the engine does not tremble at idle, balancing is performed - to balance the balance of the crankshaft with the clutch mechanism and the flywheel. This is done by drilling out parts of the part to reduce weight.

Vibration may be a consequence of installing new elements of the cylinder-piston assembly. Especially if they have a different weight compared to old components. To prevent weight changes from leading to increased shaking of the running engine, it is necessary to weigh the parts of the cylinder-piston system before assembling the power unit.

How to preserve the life of engine parts in different operating modes?

In order to extend the life of the engine, you need not only to monitor the normal number of rotations of the crankshaft. It will also be necessary to be able to operate the vehicle correctly, choosing the optimal range of work. Experts recommend upshifting in the rpm range between peak torque and maximum power. At the same time, when driving under high load (for example, when driving uphill), there is no need to allow the shaft rotation torque to drop to values ​​close to idle speed.

Danger of vibrations

The causes of vibrations that occur must be eliminated as soon as possible after the first signs of problems occur. This is explained by the fact that after vibrations, other problems often develop that can cause enormous damage to your vehicle. As experts themselves note, the greatest damage due to vibrations is caused to the car body. The first to wear out and break are the plastic elements, then gradually all sorts of fastenings, located sometimes in very hard-to-reach places, become loose. When the car shakes for a long time, the paint layer may begin to deteriorate. This already entails the formation of corrosion and the spread of rust throughout the body.

We must not forget about the harm that is caused to the power unit. The engine also suffers significantly from unnecessary vibrations. Vibration causes accelerated wear of parts, destroys the packing in the crankshaft, and then oil begins to leak. As a result, the engine cannot produce the required number of revolutions, the car accelerates more slowly, and fuel consumption increases significantly. And at the same time, engine power decreases, which negatively affects control. If you noticed that the car began to vibrate, but were able to find the reasons and eliminate them, the work is not yet completed. In addition to this, be sure to check all the parts that could have been damaged in any way as a result of the vibrations that have arisen. You can eliminate the source of vibration, but you cannot exclude the fact that some destructive processes have already been launched. The fastener has come loose, the paintwork has been damaged, and therefore new problems will potentially arise soon.

Triple

So, the first reason that provokes engine vibrations. Engine tripping is the most likely cause of unstable operation of the internal combustion engine, since when the cylinder is not working, a significant imbalance and improper distribution of the load on the crankshaft occurs. As a result, you can see the motor jerking from side to side. Also, when driving, vibration of the steering wheel is noticeably felt. At idle speed all these signs are more noticeable. The more the shaft rotates, the less strange vibration will be noticeable. But at the same time, you will notice how the car begins to absorb more fuel and noticeably lose power, especially when driving downhill.

There is only one solution in this situation - to urgently repair the non-working cylinder. If this is not done in time, coking of the crankshaft parts will soon occur. At the same time, their service life will noticeably decrease, since the fuel does not burn in the chamber, but only washes away the lubricant.

Vibration at idle

Vibrations are the rattling sounds produced by the engine and felt by the driver when he holds the steering wheel.

If there are problems with the engine, the rattling from barely perceptible becomes very strong and unpleasant.

Signs

The main symptoms of this problem include:

• increased vibration of the steering wheel, which can be transmitted to the engine body;
• engine popping;
• engine jerks and failures;
• The tachometer readings exceed the permissible values ​​for the car.

It will also be useful for you to know why the car shakes during acceleration and at high speed.

Causes

The main causes of engine vibrations include:

• engine tripping (uneven operation of the pistons or failure of one of them);
• incorrect motor mounting;
• faulty engine mounts;
• the crankshaft is unbalanced;
• the fuel system is dirty;
• improper fastening of other units;
• ignition system malfunction.
• One of the common mistakes associated with engine mounts is installing mounts from different materials.

The above reasons are valid for gasoline cars.

The reasons why the vibrations of a diesel engine have increased, due to the difference in design and operation from a gasoline engine, are slightly different:

• malfunction of the cylinder-piston group or gas distribution mechanism as a whole or in a separate cylinder;
• compression variation in cylinders;
• malfunction of the high pressure fuel pump, diesel injectors or timing belt teeth;
• incorrect injection advance angle.

Why is low engine idle dangerous?

No less a problem is reducing idle speed.

Low speeds can lead to the following consequences:

• fuel detonation in the cylinders does not occur completely;
• oil dilution;
• washing off the lubricant;
• coking of the motor.

It is also worth noting that at low idle speeds the car will stall, as it will not have enough revolutions to maintain operation. This, in turn, will increase the load on the ignition system, increasing wear on the car and reducing its service life.

Diagnostics

To carry out diagnostics, you should pay attention to the following points:

• check the injector/carburetor;
• take readings from the tachometer and pressure sensor and compare them with normal values;
• check the fastening of the motor and other components;
• run computer diagnostics of the car (if there are appropriate electronics on board).

Separately, it is worth mentioning the process of checking engine mounts, since their incorrect installation quite often causes problems, although they are easily diagnosed and corrected.

Important! Since visible problems may hide other, more serious ones, if any problems occur, you should contact a car service center.

Checking the airbags is carried out as follows: one person sits behind the wheel, opens the hood and drives back and forth in place, the second person watches the engine at this moment - it should tilt evenly in all directions. If the engine rolls a little more in one direction, then the cushion on that side should be replaced.

What measures to take in case of strong vibration

When faced with strong vibrations, you can begin to combat the problem.

Engine adjustment

Adjusting the motor, first of all, includes checking the fastenings of the parts, as well as their condition. Having ensured that they are in good working order and correctly secured, it is necessary to calibrate their joint work.

The best way to do this is to check the factory settings in the instructions and reset all settings to them. Tuning includes not only tuning the operation of the engine itself, but also related systems - fuel supply, ignition, and so on.

If parts have been replaced, it is necessary to ensure that the parts in weight and material match those that were replaced - otherwise imbalance will occur.

Did you know? If the crankshaft is too heavy, it is lightened by cutting out holes, thereby knocking off the extra grams.

Correct installation of the timing belt

Another important element in solving the problem is installing the timing belt. The belt is responsible for the connection between the crankshaft and the camshaft, and its incorrect installation will inevitably lead to disruption of the gas distribution system.

The belt is replaced as follows:

• the protective belt cover is unscrewed;
• disconnects from the sensor;
• checking the coincidence of the marks on the camshaft gear (or shafts, if there are several of them), the gas distribution mechanism drive, the flywheel, the crankshaft - this will ensure the correct valve timing;
• the old belt is removed;
• a new belt is put on: first on the crankshaft pulley, then on the camshaft gear and pump;
• two revolutions of the crankshaft are carried out, after which the marks are checked - if the belt is installed correctly, they will coincide.

Correct sequence of actions

When a driver discovers that the engine of his car begins to twitch at idle and vibrate, there is no need to immediately panic and disassemble half the car. Act sequentially, from the most likely causes to the least possible.

1. First, check the condition and functionality of the spark plugs. If there is no large amount of carbon deposits on the surface, and a good spark is formed, you can move on to the next possible source of vibration problems at idle.
2. Engine compartment. Here you need to make sure that all support cushions and engine mounts are in good condition and there is no damage. The gear shift method will help here. This way you can track which direction the slope is going and whether the motor mount is really broken.
3. The next step will be to check the fuel system. You should see how clean it is and whether any contamination has formed there. Be sure to check the condition of the filters. If they become dirty and are already in a fairly worn condition, it is better to change them. It definitely won't harm the car.
4. Software and injectors. This is true for injection engines, where sometimes you just need to update the current software of the electronic control unit. If this is not necessary, simply clean the injectors. It’s not the most common cause of vibrations at idle, but it shouldn’t be ruled out either.
5. When all the previous points do not apply to your situation, it is worth checking the weight distribution of the CPG and the calibration of the crankshaft. It is not recommended to deal with these issues on your own. It is better to visit a trusted car service center. Solving such problems requires the presence of special, complex and expensive equipment. Buying it for personal use is not particularly profitable. And if a person without the proper experience and qualifications intervenes in the weight distribution of the CPG or the calibration of the crankshaft, his mistakes can lead to even more serious consequences.

The problem of engine vibrations when idling is familiar to a large number of drivers. Only some people ignore the uncharacteristic behavior of their vehicle, while others try to quickly understand the reasons and eliminate them. It is easy to guess which of the two positions is correct. Try to listen to your car, monitor its behavior and condition, take timely measures and eliminate malfunctions in the early stages of their occurrence. It is better to prevent a breakdown than to repair the car later. Nowadays repairs are not so cheap.

Disorders in the nutrition system

Ultimately, they come down to improper formation of the composition of the combustible mixture. Typically, vibration at idle is a consequence of its depletion. It is possible to understand exactly which node or element is the source of the problem only with the help of special equipment. There are many reasons, below are just a few of them:

• fuel pump failure;
• contamination of the filter and (or) fuel line;

• clogged jets in the carburetor or nozzles in the ramp;
• incorrect carburetor settings, faulty sensors in the injection engine, etc.

Primary diagnosis of causes

If the car's power plant is working properly, vibration is not felt during idling. When it appears, and it is also intense, transmitted to the body and felt even inside the car, it is worth conducting diagnostics to determine the cause of what is happening and correct its elimination. To do this, depress the clutch and listen.

If the vibrations continue, it means that the motor is really faulty, but if they stop, there may be problems in the operation of the gearbox and the clutch itself. Moreover, the type of gearbox, whether it is automatic or mechanical, does not play any role. In any case, it is necessary to urgently go to a service station and show the car to specialists, because professionals should be involved in repairing the power unit and putting the transmission in order.

By the way: you can check the condition of the gearbox yourself. To do this, you need to pour a small amount of oil into a container and examine its condition. The presence of metal shavings in lubricants, the presence of impurities and a burning smell indicate a serious gearbox malfunction. If the oil is normal, most likely the vibrations at idle are caused by clutch failure.

A common cause is also the incorrect operation of individual engine components. In this case, shaking is felt immediately after starting the engine and even when it stops. In such situations, experts recommend paying attention to the following:

• Engine airbag (it may be faulty).
• Condition of the fuel filter (clogging).
• Fuel pump clogged.
• Condition of the spark plugs (it is possible that they will have to be replaced).
• Components of the cylinder-piston group.

How to reduce engine vibrations

If the car has a carburetor, then to reduce vibrations this element requires careful adjustment, after which the idle speed is set. At the same time, the fuel pump is checked.

On injection cars, the fuel pump, injectors, electronic control system sensors, and fuel pressure regulator in the fuel rail are also checked. Additionally, it is recommended to clean the throttle valve and check the idle air valve, which supplies air bypassing the throttle valve at idle. Vibration of a diesel engine at idle may indicate certain malfunctions of the fuel injection pump or injectors, which will also require careful diagnosis and subsequent adjustment.

Fuel system contamination

If the spark plugs and wiring are in order, the engine is installed correctly, and the protective cushions are not worn out, but the engine still jerks at idle, the cause may be contamination of the fuel system. Of course, in order to affect the performance of the car, the pollution must be really serious.

The greatest danger is posed by excessive amounts of water, soot and oil. When parts of the fuel system become clogged, the HT mixture does not burn completely, as a result of which gasoline consumption increases significantly. In addition, the engine may “sneeze” and shake.

In this case, there is only one solution. This is a thorough cleaning and inspection of all elements and components of the fuel system.

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Vibration when driving under load

There is another type of vibration - under load.

The appearance of vibrations while driving not at idle speed of the engine, but under load, always indicates problems in the operation of the engine. The occurrence of such an unpleasant phenomenon is preceded by various reasons.

Chassis imbalance

If the wheels are not balanced correctly, this becomes evident when driving at speeds of 70 km/h and above. Moreover, the force of shaking can be so noticeable that it is transmitted and felt even on the steering wheel. The problem can be solved extremely simply - by visiting a service station and balancing the wheels.

The procedure is accessible and does not take much time. It is important to note that imbalance often occurs in winter, in bad weather, when wet snow sticks to the disks, but vibrations in this case are more noticeable than on poorly balanced wheels.

Fuel system clogged

Problems that lead to engine shaking also occur due to malfunctions in the fuel system, in particular due to its clogging. They consist of problems with the fuel supply, which is why the fuel mixture is formed incorrectly. Vibrations are usually noticeable if the mixture in the cylinders is lean.

Carrying out accurate diagnostics in the current situation is possible only with the use of special equipment, and we are talking about the diagnostics of both carburetor and injection internal combustion engines. Often the problem is a faulty fuel pump or clogged fuel filters.

And also in clogged fuel injectors, unadjusted carburetor. Typically, diagnostics of the fuel supply system are performed after it has been verified that the ignition is working properly, and also that the cause of the vibration is not a broken engine mount.

Sensor malfunctions

Engine malfunctions often result from failure of the sensors that send signals to the engine ECU. For example, if the lambda probe, idle speed control, speed indicator, etc. are faulty, the control unit operates in emergency mode, which is why there is a high risk of disturbances in the formation of the fuel mixture and the resulting unpleasant consequences.

The same thing will happen if the crankshaft position sensor, phase sensor, etc. break down. You can find out what exactly requires replacement only by performing computer diagnostics, as well as deciphering the error detected by the electronic controller.

When driving

If your vehicle experiences vibration at speed that increases as it accelerates and does not stop while driving, the problem may be wheel imbalance. In addition, shaking when driving is associated with a malfunction of suspension and electrical parts:

• shock absorbers, struts;
• support bearing;
• tie rod end;
• hinges;
• high-voltage wire break.

When a high-voltage wire breaks, the car begins to vibrate when driving and a characteristic crackling sound is heard. Finding the location of the breakdown is quite simple; a spark is noticeable when the engine is running and idling. But if the electrical wiring is in order, but the appearance of extraneous sounds under the hood is noticeable, you should check the electronic sensors.

Dual mass flywheel

Symptoms of damping flywheel failure:

• creaking, grinding noise when starting and stopping the power unit;
• rumbling sound when the engine is idling;
• vibration transmitted to the body and interior (with non-critical wear only in cold weather).

The reason for this behavior is the backlash of the elements of the spring-damper system, which is designed to dampen torsional vibrations. On cars with manual transmission, to check the flywheel, just squeeze the clutch. If the engine begins to run smoother and vibrations have decreased, it means that the reason for unstable idling is the dual-mass flywheel. The owner of a car with a robotic gearbox is left to rely on indirect signs and defects after disassembly.

Knocking and uneven operation when cold

Accelerated wear of cylinders and pistons is a real problem for many owners of Volkswagen and Skoda cars with gasoline engines. Recently, cases of scoring in cylinders on Hyundai cars have become more frequent. Due to the tendency to lighten the CPG elements, reduce the thickness of the piston rings, the flame zone and the length of the skirt, repositioning the pistons is associated with heavy loads. Local overheating associated with operating a car in traffic jams (disturbed air flow, long periods of idle time), improper engine warming up in winter, lead to wear of the CPG.

As a result, the engines begin to knock when cold. As it warms up, the knocking, and with it the increased vibration in the body, stops.

Signs of Engine Vibration

On premium cars, especially if they have a multi-cylinder internal combustion engine, vibrations may not be felt on the body. All supports, fastenings, cushions are made of high quality material. In this regard, even turning off one cylinder does not particularly cause vibrations on other components. The engine seems to be isolated from the rest of the car.

Especially at idle, engine vibration affects the body of domestically produced cars. Also, in foreign-made cars with 4-cylinder engines, the impact on other components is felt.

Thus, the imbalance is always transmitted to the body and the gearbox handle. Let's look at how to identify and eliminate vibrations in engine components on a car with your own hands.

Improperly secured motor

This is also one of the common reasons why vibration occurs in the body at idle. Most often, this problem is associated with wear and tear on one of the mountings on which the engine is mounted.

How to find out flaws in engine mounting? It's very easy to do. To do this, you need to open the hood and call an assistant to alternately engage neutral, reverse and forward gears. And at this time you should pay attention to the position of the engine on the supports. Thus, you alternately unload the pillows that hold the motor. With each new gear change, the engine will deflect in different directions at the same angles. If it deviates more than usual in any direction, it means that the pillow needs to be replaced in that place.

Diesel vibration at idle

At first glance, everything is simpler here: there are no spark plugs, no distributors. However, the “shaking” of a car equipped with a diesel engine indicates more serious and “costly” problems:

1. Failure of the injection pump, which can only be checked using special equipment.
2. Injector contamination. Their cleaning is carried out in specialized technical centers.

If vibration occurs at idle, checking the diesel unit should begin by determining the compression in the cylinders. If it does not meet the standard, the mixture will not ignite and the engine will begin to shake. The second stage of testing is to check the alignment of the marks on the power unit cover and the camshaft pulley. If the injection angle is incorrect, the diesel engine will operate unstably.

Vibrations in diesel engines

In addition to the main factors, increased vibrations at idle in diesel units are caused by 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 components of the fuel supply system, for example, on the degree of their contamination. Contamination occurs due to particles and impurities (including water) from the fuel and air entering the fuel system components due to poor filtration.

The culprit for increased oscillations may be a malfunction of the fuel supply system components and, first of all, the injection pump.

If vibration is felt the first time after starting a cold engine, but disappears after warming up, then the glow plug is faulty. In addition, the serviceability of the engine should not be excluded from the list of reasons - the presence of a compression level that meets the standards.

Let's sum it up

As you can see, the causes of engine vibrations at low speeds and idle pose a danger to the car engine and its individual parts. Any vibrations not only impair operating comfort, but also harm the engine.

Only timely recording of the above signs of vibration, immediate elimination of the causes, as well as regular technical inspection are the key to long and safe operation of the internal combustion engine and the entire vehicle.

Sources

• https://FB.ru/article/162048/vibratsiya-na-holostyih-prichinyi-i-metodyi-ustraneniya
• https://scart-avto.ru/remont/vibratsiya-dvigatelya-na-holostyh-oborotah-prichiny-pochemu/
• https://diagnozbibike.ru/neispravnosti-dvigatelya/vibracziya-dvigatelya-na-holostyh/
• https://nahybride.ru/dvigatel/vibratsiya-dvigatelya-na-holostyh-oborotah
• https://avtodvigateli.com/neispravnosti/vibraciya-na-xolostyx-oborotax.html
• https://dvigatels.ru/uhod/vibraciya-dvigatelya-na-holostyh.html
• https://avtodvigateli.com/neispravnosti/vibraciya-dvigatelya-na-xolostyx.html
• https://KrutiMotor.ru/vibratsiya-dvigatelya-na-malyh-oborotah-prichiny/

Tips and tricks

As you can see, to prevent vibrations, regardless of whether the engine is carburetor or injection, it is necessary to maintain the cleanliness of the fuel system, the functionality of the ignition system, etc.

The fuel pump and ECM sensors, fuel and air filters deserve special attention; the fuel injectors, idle air valve, and accelerator pedal need to be adjusted. It is important to understand that vibrations that are not eliminated in a timely manner lead to the following negative consequences:

• cracks in the car body;
• gradual unscrewing of even the most tightly tightened nuts and bolts (which can lead to an emergency);
• premature wear of parts, resulting in, for example, oil leakage, destruction of bearings, seats, fasteners, etc.

We also note that sometimes motorists are faced with a problem such as a drop in speed to 500 rpm. on a warm engine at a rate of 750-900 rpm. As a result, the internal combustion engine begins to vibrate strongly. This indicates problems with the throttle and sensors (for example, TPS).

Also, drivers often deliberately lower idle speed to save fuel (especially if they have LPG). At the same time, the consequences of engine vibrations will subsequently lead to repairs, which in cost will cover all the savings on fuel.

Even while driving, it is important to consider at what speed to drive. The fact is that if the car is used incorrectly, vibrations can also occur. To prevent this from happening, you should adhere to the following rules:

• upshifting must be done between peak torque and peak power;
• when vibration occurs, it is necessary to switch to a lower gear to avoid engine damage;
• if the car does not pull, you must also switch to a lower gear, but do not allow vibrations to occur.

This approach will avoid premature wear of parts, while ignoring it will quickly damage engine pistons, transmission bearings, clutch basket, crankshaft liners, etc. Carbon deposits and wear appear on the walls of the cylinder liners; due to constant vibration, oil seals begin to leak, and shafts begin to run out.