We have already looked at the reasons why the steering wheel vibrates, and today it is our turn to study the nature of other vibrations - from an engine running on Idling. This phenomenon is unpleasant and threatens serious problems for the car. Therefore, prompt diagnosis and elimination of vibrations of the power unit is in the interests of everyone who cares about their vehicle owner.

Causes of engine vibrations at idle

During normal operation of the power unit at idle, vibrations have nowhere to come from: at this time, torque from the engine is not transmitted through the gearbox to the driveshaft and all serviceable transmission components should operate without vibrations. If at idle speed the engine begins to vibrate, this is a direct sign of a malfunction that could arise for a number of reasons. Let's look at them in detail.

Reason #1. One or more engine cylinders are operating intermittently. This breakdown is known to many drivers - usually in such cases they say that the engine is malfunctioning. We recently talked in detail about why the engine stalls 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. There are several reasons for such a malfunction, we will list only the most common: a decrease in the compression level in the cylinders, an excess or lack of air in the cylinders, too little or too much fuel getting into the cylinder, and, finally, earlier or, conversely, late ignition of the air-fuel mixture in the combustion chamber . Each of these reasons can lead to engine vibrations at idle, which can increase or decrease, but do not stop. From the engine, these vibrations are transmitted to the body and steering wheel of the car, causing discomfort to the driver and passengers. If this problem is not corrected, the result may be disastrous - a major engine overhaul will be required.

Reason #2. Loose fastenings power plant . Another fairly common cause of vibration when the engine is idling. We discuss this malfunction in detail in our article on the causes of vibrations on the steering wheel, so we will outline this problem briefly. As a rule, engine vibrations due to loose mounts are most clearly diagnosed when the car is stationary. When you start moving and pick up speed, the vibrations only increase. This problem most often occurs in machines with high mileage, in which, due to driving on poorly paved roads, all the fastenings of the power unit become loose.

Reason #3. Broken engine mount. Strong engine vibrations at idle can also occur for a more serious reason than the one described above. Vibrations of the power unit, during which a characteristic grinding sound of metal on metal is heard, indicates a breakdown of the engine mount - in common parlance, the engine mount.

There are four of them - front, rear, bottom and top, and any of them can break. Most often, the front engine mount fails, since it is this that bears the greatest inertial and dynamic loads during vehicle operation. If one bursts, then, most likely, another one will die for a long time (for example, front and back, upper and lower), so you need to carefully inspect all the pillows.

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

Reason #5. Incorrect crankshaft installation. This reason is one 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-out crankshaft the mechanic did not calibrate the part, which after installation does not work correctly, causing strong engine vibrations at idle speed.

How to rid an engine of vibrations

Having determined the reason why the power unit vibrates at idle, you can begin to “treat” it. Let's consider engine repair options in each individual case.

If vibrations of the power plant occur because it is tripping, then this damage must be corrected depending on 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 failed. To understand exactly which part has broken and is preventing the cylinder from working, you will have to disassemble the motor.

The reason for low compression may lie in a worn piston, piston rings or valves. In this case, it will only help complete replacement a failed part (in no case do we recommend restoring these elements yourself, so that you don’t have to do more serious engine repairs in the future).

Engine tripping and vibrations caused by uneven air entering the combustion chamber can be corrected by replacing the contaminated one and eliminating cracks in the air supply system line. Or - by replacing failed position sensors throttle valve or mass air supply. If the engine stalls due to increased or decreased fuel supply to the cylinder, you will have to: a) inspect and then clean the injectors (if after cleaning the injector the problem is not resolved, 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) determine ECU errors and reset them.

Is the engine shaking and vibrating at idle due to failures in the air-fuel mixture ignition algorithm? The high-voltage wires may have failed. them for new ones.

If the fastenings of the power unit have become loose, then we arm ourselves with wrenches with heads corresponding to the bolts and tighten all the loose bolts. We replace the broken engine mounts with new ones - there is no point in trying to restore them, it will cost you more.

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

If an incorrectly installed crankshaft, then you should dismantle it, calibrate it to special equipment and put it back in place. After this operation, the engine will almost certainly stop “dancing” and you will again be able to drive your car without experiencing vibrations that get on your nerves.

A serviceable engine creates a minimum of vibration when idling. If the vibrations are strong and are even transmitted to the body, this indicates that some of its components are not working properly. Next, we will look at exactly what malfunctions lead to vibrations and how to eliminate them.

1 Is the engine to blame - primary diagnosis

Idling is the operation of the engine in neutral gear mode or with the clutch disengaged. Therefore, if you notice that engine vibration appears at idle, and at the same time it is transmitted to the body, make sure that the reason lies in the engine itself. To do this, simply press the clutch pedal. If the situation has not changed, it means that the engine is indeed vibrating. If the vibrations stop, problems should be looked for in the gearbox (no matter whether it is automatic or mechanical) or in the clutch itself.

In this case, it is better to show the car to specialists, since the transmission is a very complex system that must be serviced by professionals. To check the condition of the box yourself, you can drain a small amount of oil and examine it. If there are metal shavings in the oil, and the lubricant itself is cloudy and has a burning smell, there can be no doubt that the gearbox requires serious repairs. If nothing like this is found in the oil, suspicion falls on the clutch.

2 The engine stalls - what happens when there is no spark?

The most common problem is motor tripping, i.e. uneven operation of the cylinders. Why does this situation arise? The reason most often lies in the ignition - a weak or inconsistent spark in the spark plug leads to the fact that the combustible mixture does not ignite, i.e. one cylinder stops working for a while. Hence the term - tripling, i.e. Instead of four cylinders (applies to four-cylinder engines), only three operate simultaneously.

Of course, there are situations when several cylinders operate unstable at once, and as a result, the vibration increases even more. Most often, tripping occurs due to a malfunction of one or more spark plugs. Moreover, spark plugs fail gradually - initially the spark plug produces a strong spark, but over time it weakens, and then gaps appear. Therefore, beginners usually do not immediately determine the malfunction. Gradually the problem progresses - at idle the body begins to vibrate, and sometimes the steering wheel even shakes. This is also accompanied by a loss of traction, as a result of which dips appear during acceleration, and when driving uphill, the car begins to twitch. In such cases, you just need to replace the spark plugs.

Spark plugs need to be changed every 15–30 thousand kilometers, depending on the make and condition of the car.

If replacing the spark plugs does not help, check other ignition elements - first of all, the high-voltage wires. When one of the wires “breaks,” you can hear a characteristic crackling noise under the hood, and in the dark you can even see small flashes. Spark plug tips can also cause spark problems. Please note that ignition faults lead to a number of negative consequences – accelerated wear engine parts and other components. Therefore, it is necessary to eliminate the cause of vibration immediately after its detection.

3 Mounting problems - how to test cushions?

The cause of vibration can be worn out engine mounts (mounts) or, conversely, too hard (vibration appears after installing new mounts). Supports perform two important functions at once:

• serve as elements on which the power unit is attached to the body;
• dampen engine vibrations, as a result of which they are practically not transmitted to the body.

It is very easy to distinguish vibration caused by problem pillows, since it does not depend on the operation of the cylinders. Those. the engine can operate quite stably. At the same time, when you press the gas pedal and when starting off, vibrations may increase. When accelerating and braking, knocking noises may even appear. To verify that the airbags are faulty, you can perform a visual diagnosis. For this you will need a partner.

One person rocks the car, moving sharply forward and backward, and the second watches the movement of the engine under the hood. The motor should lean slightly to the sides, and the angle of inclination should always be the same. If the power unit, as they say, “dangles,” then it is necessary to replace the pillows. It must be said that it is recommended to change pillows, even if they have no visible damage. After installing the new supports, they need to be adjusted. Incorrectly adjusted fasteners can also cause vibrations and knocking.

4 When should balancing be done?

If vibrations appear at idle after engine repair, then it is quite possible that they are associated with improper balancing of the crankshaft with the flywheel. The fact is that engine repair usually involves grinding the crankshaft, i.e. The weight of the part changes slightly in different parts of it. To balance this unit, extra grams are drilled into the crankshaft body.

In addition, when major renovation engine, the pistons are usually replaced. Accordingly, the delicate weight balance may also be disrupted. Therefore, before assembling the engine, specialists also carry out weight distribution of the piston group. The difference in weight often leads to serious vibrations, which are especially noticeable at low speeds. Therefore, engine repairs can only be trusted to highly qualified specialists who have all the equipment necessary for this.

If vibrations did not appear after repairs, but during the operation of the vehicle, this may be caused by failure of the balancing shafts. It must be said that balancing shafts are not installed on all engines, but only on those that are initially prone to vibration. In particular, three-cylinder car engines have such a shaft. VAZ 1111 And VAZ 1113.

5 Why is it important to install the timing belt correctly?

If vibrations occur after replacing the timing belt, it is quite possible that it was installed incorrectly. Let us remind you that this drive belt, which transmits rotation from the crankshaft to the camshaft. Thanks to him, the gas distribution system, i.e. valve, works synchronously with the strokes of the piston system. If the belt is installed incorrectly, for example, there is a shift of at least one tooth, the valves begin to open and close at the wrong time.

This leads to dips in engine operation and tripping. Accordingly, at idle, as in the case of a faulty ignition, there is strong vibration, which is well felt on the steering wheel and the entire body. The problem is being solved correct installation belt Therefore, it is advisable to replace it only in service centers.

6 Problems with fuel supply - what are they associated with?

Unstable engine operation at idle is very often associated with a problem in fuel system. Moreover, there are a huge number of possible malfunctions. Most often this is a clogged carburetor or injector. To wash the latter, a special stand is used, which provides injection flushing liquids under a certain pressure.

The carburetor does not need a stand. Its cleaning is carried out using chemicals and compressed air. In parallel with cleaning the carburetor or injector, the operation of the fuel pump is checked, which may also be the cause of failure. stable operation motor. From time to time, the pump needs to replace gaskets, diaphragms and other elements. Problems with the fuel pump are often accompanied by the appearance of a fuel smell in the cabin.

Vibrations diesel engine often associated with fuel injection pump malfunctions(fuel pump high pressure). This is a very complex and expensive unit that is responsible for the following functions:

• injection required quantity fuel under high pressure (the amount of fuel is determined by the load on the crankshaft);
• determining the exact moment of the start of fuel injection into the cylinder.

Therefore, when a fuel injection pump fails, it requires complex diagnostics and careful adjustment.

7 Other Common Causes of Vibration

Vibrations at idle can also occur for other reasons. Thus, interruptions in engine operation may indicate that low-quality fuel has been poured into the tank or water has entered it. Vibrations in this case are usually accompanied by high fuel consumption and loss of engine power. To solve this problem, it is necessary to drain low-quality fuel from the tank and refill good gasoline or solarium. Of course, the vibration will not disappear immediately, since it is necessary to use up the remaining fuel.

If interruptions in engine operation are not related to fuel quality, you should check the air and gasoline filters. The air filter can be inspected visually. To do this, unscrew the housing cover, remove the filter and look through it at the light. If there is no clearance, air filter needs to be replaced.

As for the fuel filter, it needs to be changed on average once every two years or every 25,000 km. If low-quality fuel is poured into the car, the service life of the filter can be greatly reduced. A clogged fuel filter manifests itself at idle and causes failures during acceleration. In some cases, the engine may stall at idle speed.

IN modern cars, especially domestic production, unstable work power unit at idle may be caused by malfunctions of the following sensors:

• MAF (mass air flow sensor);
• IAC (idle speed sensor);
• TPS (throttle sensor);
• CPRV (camshaft position sensor);
• DPKV (crankshaft position sensor).

To diagnose their operation, it is better to contact service center where the necessary equipment is available. Since the sensors cannot be repaired, the fault can only be eliminated by replacing them. To do this, of course, it is necessary to accurately identify which of the above elements is not working correctly. Please note that if you do not replace a faulty sensor in time, then when it completely fails, the car most likely will not even start.

Incorrect operation of the mass air flow sensor may be due to depressurization of the air duct. Owners of VAZ cars often encounter this situation.

Vibrations often appear as a result of excessive load on the generator, i.e. when simultaneously turning on various electrical equipment, such as lighting devices, heating rear window, air conditioning system etc. In this case, the vibration usually disappears after pressing the gas pedal, as the speed of the generator itself increases. If the situation repeats frequently even with a small load on the generator, the generator itself should be diagnosed.

Sometimes vibration can be caused not by the motor, but by some mounted unit in contact with the body. Inspect carefully engine compartment. If the part in contact with the body is not identified, drive the car onto an overpass and inspect it from below. These are, perhaps, all the main reasons why an engine may begin to vibrate at idle. Try to identify and eliminate them when the first symptoms appear. Otherwise, the car may require more complex and expensive repairs over time.

Idle speed is the speed at which the minimum part of the load falls on the engine crankshaft. An example of such motor operation can be considered when the clutch is disengaged (there is no load on the shaft) or when it is engaged and the gearbox is set to the “neutral gear” position (in this case, most of the load is transferred). Idle speed can fully reflect the overall picture of the engine’s condition, and therefore, when assessing any malfunctions, the engine is started in this mode. Today we will try to figure out why the engine vibrates at idle, what are the consequences of this malfunction and how repairs are made in this case.

Main causes of motor vibration

Engine idle speeds on all cars are clearly standardized. In most cases they range from 800 to 1200 rpm. This figure depends on the type, volume and other features of the engine, as well as on climatic operating conditions. In addition, this mode of engine operation must be completely stable. The fact is that fuel consumption will increase significantly, and the wear of many parts can reach a critical point.

Now it's time to understand what causes engine vibration. First of all, this is due to poor performance of one or more cylinders. For example, if incomplete combustion of fuel occurs in 1 cylinder, does not occur at all, or the wrong fuel mixture is supplied there, then the piston begins to move by inertia and upsets the balance of the crankshaft. Consequently, it begins to vibrate, and this reaction is reflected in the engine itself. Below we will list common causes of poor engine performance, and then we will tell you what to do in this case.

• Ignition system. Many drivers check this first. There is such a concept: . This means that it vibrates due to one cylinder not firing. This happens when the spark plug becomes unusable. You can verify this if you sharply press the gas pedal - in exhaust system you can hear a characteristic lumbago.

To find out, you need to start the engine and one by one pull out the high-voltage cables from the contact terminals of the spark plugs. If the spark plug turns out to be in good condition, the engine will begin to sharply lose speed and even stall. In the opposite case, when when removing the cable, the behavior of the motor does not change or changes slightly, then you have discovered.

Supply system. The longest and most capacious problem. Checking the power system begins with the serviceability of all filter elements. These include fuel filters and airy. All of them must be clean and suitable for further use. Next, you need to check the booster device or fuel pump. On cars with a carburetor engine, this is done quite simply - if the pump is faulty, fuel will not come out through its hose at all, which means it will not be in the filter and the engine will most likely stall in half a minute.

• Next in line is carburetor. Him in mandatory leads to poor-quality mixture formation, which means that gasoline and air will be dosed incorrectly, which will lead to bad work cylinders, and as a result - vibration.

The injection engine is also no exception. It also includes their level of pollution. In addition, the source of a sharp increase in idle on the injector may be the controller itself, the firmware of which has been damaged.

• Engine mount. If the installation under the motor is incorrect or tightened too loosely, then this becomes the third reason for increased engine vibration.
• Surely the engine is not yet warmed up. Before starting to drive, it is customary to warm up and move the engine, that is, let it run without load. It is possible that in this case it will work unevenly.

Why is engine vibration harmful?

Vibration itself is a sign of engine malfunction. If it vibrates, it means that one of the systems is not working correctly, and the engine is a collection of these systems where everything is interconnected. This means that the failure of one leads to the failure of the other. For example, running an engine on three cylinders wears out the piston and connecting rod and causes the crankshaft to bend. In addition, on carburetor engines because of this, it may even be impossible to start the car after this.

In addition, vibration has a bad effect on the condition of the body as a whole. The first to suffer are the plastic elements of the interior, which become loose and when driving on uneven roads begin to produce an unpleasant knocking and crackling sound. If the vibration lasts long enough, there is a risk of damaging the car's paintwork. It simply comes away from prolonged shaking and then the body is quickly exposed to the adverse effects of corrosion.

How to get rid of engine vibrations?

• To solve the problem associated with the adverse effects of vibration, it is first necessary to use the solutions provided by the manufacturer. Besides correct selection, they need to be tightened well.
• Next is produced setting up the ignition system. This is not for carburetor cars. difficult process and instructions for its implementation can be found on the website. After the ignition is set correctly, high-quality spark plugs and high-voltage cables are selected. As for injection engines, the ignition is configured on its own with the software correctly installed.
• Next up is the fuel supply system. First you need to make sure that all filters are clean and replace them if necessary. Next, the carburetor is adjusted. For each device model, it is performed individually in accordance with the instructions.
• If your car is equipped injection engine, then the issue can be resolved by installing new software and cleaning the injectors.

Why does the engine shake when idling?

The characteristic shaking of the engine can occur both immediately after starting and when it is warm. For example, when stopping in a traffic jam or at a traffic light.

When the engine jerks, it is similar to tripping, but the symptoms are somewhat different. The internal combustion engine shakes unevenly, not cyclically. This often manifests itself for reasons not related to the combustion of the fuel mixture. First of all, in such cases, it is necessary to check the condition support cushions engine. Perhaps a heavy unit simply resonates at low speeds, and torn pillows are not able to dampen vibrations.

If everything is in order with the supports, we begin to look for faults in the ignition and fuel supply systems to the cylinders. Rings and valves can also be the culprits of vibrations, but this rather refers to the so-called. tripling.

The material was prepared by specialists from the website Skrutit-speedometr.ru, whose activity is professional odometer adjustment in Moscow without traces of interference in the system and with a guarantee.

Why does the engine shake at idle: causes and solutions

This may happen for the following reasons:

• Gasoline quality. If the problem occurs after the next refueling, it is most likely to blame bad fuel. Combustion occurs unevenly, with different intensities. Unlike tripping, the engine shakes only at idle, when the fuel mixture supply is at a minimum. On increased speed the influence of low-quality fuel is not so great, and the operation of the internal combustion engine can return to normal.
• Fine fuel filter. If it is clogged, the required pressure is not created in the ramp. Detonation occurs in all cylinders simultaneously.
• Air filter may also cause vibrations. When looking for the reason why the engine shakes, many car enthusiasts neglect to inspect the air vent. If you regularly drive on dirt roads, or have been using your car intensively when poplar fluff fell out, it may become clogged long before the scheduled replacement date.
• Common Problem – candles. The electrodes are clogged, but sparking does not always disappear. It is necessary to clean (or replace) the problematic elements and check the gap.
• Crankcase ventilation system. In addition to the main malfunction - disruption of gas circulation and depressurization of the engine, the reason lies in the fact that pieces of delaminated tubes and fittings can get into the intake manifold.
• Idle air control (in injection systems). It often becomes clogged with particles from the crankcase, and the air supply at idle is uneven.
• Idle jet (or solenoid valve) in carburetor systems. If these nodes are thoroughly clogged, the motor will trip. And if there are small fragments of dirt deposits, that same shaking occurs. Removable by simple cleaning.
• It wouldn't hurt to check mass air flow sensor. Inspect the connector contacts, measure the voltage.
• And finally, one of the main reasons is knock sensor. If it periodically fails, the ECU does not receive information about uneven fuel combustion and continues to form the fuel mixture as normal. The sensor parameters are checked by a diagnostic scanner. Performance can be assessed in a primitive way: connect an ohmmeter and gently tap the housing. The vibrations of the sensor will cause the voltmeter needle to move (the readings should increase and then drop to zero).

More serious reasons why the engine shakes at idle

The timing marks of the timing mechanism have gone astray. If the problem is not corrected immediately, you may end up with a piston meeting the valves, followed by a major overhaul of the engine.

Compression in cylinders. If there is wear in the entire cylinder head group, the power unit shakes. If in one cylinder, it will triple.

Bottom line. When the first symptoms appear, you must immediately find out the reason why the engine is jerking. Even with weak vibration, further operation (until repairs) is undesirable.

Coordinated operation of all systems and mechanisms car engine- the key to his longevity. The appearance of vibration processes in the motor indicates that a malfunction 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 eliminating the problem as quickly as possible. In this article, you will learn what causes vibration in the car interior 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, vibration is inevitable. However, the driver and passengers do not feel it, thanks to the special design of the crank mechanism. Sometimes the engine begins to vibrate so strongly that you can even feel it in the cabin. At idle speed, as a rule, this is most pronounced. This vibration indicates that something is wrong with the motor.

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

1. Valve timing fault.
2. Problems with the ignition system.
3. Power system malfunctions.
4. Sealing failure vacuum booster brakes
5. Malfunction of control sensors of the ECU (electronic control unit) of the motor.
6. Engine mount failure.

Valve timing fault

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

The displacement of marks occurs involuntarily. The main reasons for this are: stretching of the timing belt, incorrect tension, incorrect marking during repairs. The same problem can occur in an engine with chain drive Timing belt, as, for example, in the Z22SE engine. Vibration in the cabin at idle in a car with this power plant occurs due to poor 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 an engine with a timing belt, the problem is solved by combining the above marks, which cannot be said about engines like Z22SE. Vibration in the cabin at idle speed in such power plants can be eliminated, as a rule, only by replacing the hydraulic tensioner, and sometimes the entire timing belt 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 expected, or is absent altogether, a failure occurs. It manifests itself in approximately the same way as in the previous case: the engine trots, stalls and vibrates.

The following problems may occur in the ignition system:

1. Faulty spark plugs or increased gap between electrodes.
2. High voltage wire failure.
3. Malfunction of the ignition distributor (distributor).

Checking the spark plugs

It is better to start checking the system with spark plugs. 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 engine type). If the engine runs rough and vibrations appear, then you need to check the spark plugs. This is done quite simply - you need to remove the caps of the candles one by one. If, when removing the cap, the engine begins to vibrate even more strongly or stalls completely, this spark plug and its high voltage wire OK. Having returned everything to its place, you need to check the remaining spark plugs. If, when the cap is removed, the engine operating mode remains unchanged, it means that the cylinder for which this spark plug is responsible does not work, that is, the fuel in it does not ignite.

To solve this issue, you need to inspect the spark plug 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 serviceability of the spark plug, you need to:

1. Remove all caps.
2. Unscrew the non-working spark plug.
3. Put a cap on it.
4. Place the spark plug on a surface that has contact with the vehicle's ground (for example, a valve cover).
5. Ask an assistant to turn on the ignition and idle the starter.
6. Check for spark at the spark plug.

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

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

Checking the high voltage wire

The high voltage wire is checked using a multimeter. To do this, you need to turn on the device in ohmmeter mode and set the measuring range to 20 kOhm. The wire should be disconnected from the distributor cover and the cap removed from it. The probes of the device must be connected to the two ends of the current-carrying wire. If the wire is working properly, then the resistance is 3-10 kOhm, depending on its type. The difference is in the resistance of all high voltage wires 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 are doubts about the serviceability of the distributor, first of all you need to check whether the wires are connected to its cover correctly. As a rule, there are numbers on the wires and distributor that correspond to the cylinder number. If you confuse them, vibration in the cabin at idle, tripping and other problems may occur. Oxidation of the contacts of the distributor cap also often leads to a similar effect. You can check their condition by simple inspection. At the same time, it is worth paying attention to the integrity of the contact carbon located in the center of the lid. If it wears out, spark power may decrease. The lid itself is also worth checking. The fact is that it can be pierced, which leads to the loss of part of the current.

In addition to the reasons listed, vibration can occur due to excessive load on the generator. This happens when the driver simultaneously turns on many electrical appliances (heater, headlights, heated rear window, heated seats, and so on). As the load increases, the generator, which is designed to produce a certain amount of electric current, simply does not cope with the task. As a result, the spark at the spark plug electrodes is insufficient.

Power system malfunctions

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

Accurate diagnosis of this system is possible only with special instruments. This applies not only to carburetor engines, but also to injection engines.

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

1. Pump failure.
2. Clogged line and fuel filter.
3. Clogged jets (for carburetor engines) and coarse filter.
4. Clogged injectors (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 looked for in the fuel system only when there is 100% confidence in the functionality of the ignition system. It is recommended to start checking with the fuel pump and line, and then move on to diagnosing the carburetor or injectors.

Breakdown of the vacuum brake booster

As practice shows, not everything car owners can connect braking system with motor vibrations. In fact, brake malfunction often causes vibration processes. Before we find out how such a breakdown is diagnosed, let’s understand its origin.

The vacuum brake booster is connected to the engine intake manifold via a check valve and hose. The last two elements are designed to create a vacuum in the amplifier. This occurs due to the rarefaction of air formed during intake manifold when the pistons move. 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 leads to a lean fuel mixture.

Diagnostics of the vacuum brake booster

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

Once you are sure that the vibrations are caused by the brake booster, you need to inspect the air hose. To do this, it is recommended to remove it by loosening the clamps securing 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 serviceability of the check valve by removing it from the vacuum booster housing. To do this, it is recommended to use a rubber bulb placed on a fitting included in the vacuum body. By pressing on it, you need to release air through the valve. If everything is in order with the valve, air will flow out freely and not flow back. If you don’t have a bulb, you can simply blow into the wide fitting, and then into the narrow one. In the first case, the air should pass freely, and in the second, it should not pass at all. If a malfunction is detected in the check valve, 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 unit control, the motor may begin to operate unstably. If the lambda probe, fuel consumption sensor, idle air control, throttle sensor and other elements break down, the computer works in emergency mode, incorrectly forming the fuel mixture. To determine which sensor has broken down, you need to read and decipher the error code, which is determined using an electronic controller.

Motor mount malfunction

The causes of vibration in the cabin at idle may concern completely different parts. engine compartment. Sometimes the problem lies in the engine mount. As a rule, the front supports fail. Due to drying out, sagging, or even complete deformation of the cushions, the engine mass 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 tightening.

Vibration in a diesel engine

As practice and reviews from owners show, vibration in the cabin at idle can also occur in diesel cars. On the one hand, everything is much simpler here - no wires, spark plugs or distributors. However, on the other hand - vibration diesel engine associated with more serious problems. The first and most common of these is a breakdown of the high pressure fuel pump. You can check its suitability for work only at a special stand, and not every auto mechanic will undertake repairs to the unit. Second popular problem is a blockage fuel injectors. It can be eliminated by cleaning using special equipment.

If on diesel car There are vibrations in the cabin at idle, it is recommended to start diagnostics by checking the compression in the cylinders. It is the key to 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 burn completely.

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

You should also not forget about the engine suspension. As is the case with gasoline power unit, due to stretched mounts and dried out cushions, engine malfunctions may begin. By the way, under load they appear even more strongly than at idle.

Conclusion

Today we looked at the main causes of vibration in the cabin at idle. Finally, it is worth noting that a car consists of a huge number of mechanisms, the failure of which can directly or indirectly affect the operation of the engine. Sometimes drivers, after double-checking the performance of all the systems discussed above, still do not get rid of the problem. This happens especially often among owners of a Chevrolet Lacetti. Vibration in the cabin at idle in this case is a more serious problem and requires professional intervention.