Jerking when starting the car

Do you experience jerking or vibration when starting from a stop? In most cases, the cause of the breakdown is a malfunctioning clutch.

Correct diagnostics saves time and money, so do not rush to immediately begin repairing the clutch and replacing failed parts. First, use simple tips to eliminate malfunctions that may be associated with the fact that the car jerks when starting to move.

First, warm up the engine to operating temperature. Secondly, make sure there are no problems with the power and ignition system.

If after the work done the jerking when starting does not go away, then use the list of clutch malfunctions and methods for eliminating them below.

Deformation of the driven disk.

Clean the splines from dirt, remove minor damage with a file. If the splines are significantly worn or damaged, replace the transmission disc and/or input shaft. Before assembly, apply CV joint grease to the splines.

Replace the flywheel or clutch housing and pressure plate assembly (clutch basket).

Malfunctions of car components often make drivers very nervous. Engine or gearbox breakdowns can cause large unforeseen expenses, so it is better to solve problems that arise with them immediately. If the car jerks when starting off, this does not mean anything good. However, the problem may turn out to be trivial and cost a pretty penny, but it may also happen that the transmission or engine will have to be repaired. Let's figure out why the car jerks when starting off. What should you pay attention to first?

Driving style

Beginners often abruptly release the clutch pedal when starting, which is why the car jerks. There are no breakdowns here, you need to learn to drive the car by smoothly adding gas and releasing the clutch.

You need to intuitively feel at what point the clutch starts to engage. Try to practice and get moving a few times. On a car with an automatic transmission there is no clutch pedal. Therefore, to start moving smoothly, just gently press the gas, turning the gearbox into “drive” mode.

How it works

Such assistants work on the basis of a dynamic stabilization system.

In fact, it is a software extension installed on many vehicles. To be fair, HSA cannot be called an independent and independent system.

The system is activated fully automatically. The participation of the driver himself is not required. He doesn't need to press any buttons or levers. In most cases, auto-activation occurs when the sensor detects a vehicle tilt angle of 5 degrees or more. Moreover, this angle can be adjusted to a smaller or larger direction so that the driver can use the capabilities of the electronic auxiliary assistant as comfortably as possible.

To get underway, the driver must, in the absence of HSA, quickly remove his foot from the brake, or turn off the handbrake, and start as quickly as possible. Otherwise the car will pull back.

When the brake pedal is released, the brake system itself continues to function. This will happen until the throttle valve opens.

Malfunction of CV joints

On cars with front-wheel drive, torque is transmitted to the wheels through special drives - constant velocity joints. If they are worn out or out of order, there will be jerking when moving away. People call the CV joint a “grenade” because of its appearance.

The following signs can be used to determine the serviceability of grenades:

Increased play in CV joints when moving back and forth.
A characteristic crunch when turning sharply with the addition of gas.
Knocks while moving.

Most often, the cause can be eliminated only by replacing the grenades, but sometimes they are sorted out and lubricated. Although this doesn't help for long. If you have an inspection hole or overpass, a standard tool, then you can do everything yourself.

Grenades are replaced in the following order:

Remove the wheel.
Unscrew the hub nut.
Remove the ball joint.
Pull out the wheel drive assembly with two grenades.

Next, you need to remove the covers, clamps and knock the CV joints off the axle shaft. New parts are installed in the reverse order.

There may be individual features of replacing grenades, depending on the make of the car.

Information letter No. 5-17 dated 01/23/17

When owners of LADA cars of the KALINA, GRANTA, PRIORA, VESTA families, equipped with a 1.6 liter engine and gearboxes 2180/2181/2182, complained about “Vibrations, jerking when starting the car”

Carry out diagnostics according to the attached methodology, Appendix 1.

If you need to replace the clutch kit:

If the vehicle is equipped with a driven clutch disc 21703-1601130-30
, in the absence of violation of operating rules, replace the clutch kit under warranty with: pressure plate
21703-1601085-30
, driven disc
21703-1601130-31
;
If the vehicle is equipped with a driven clutch disc 21703-1601130-31
(standard installed only on LADA VESTA GFL120 (KP 21827) vehicles) or a driven clutch disc
21703-1601130-32
(standard installed only on LADA VESTA vehicles GFL110 (KP 21807)) it is necessary to draw up a CLO with a description of the work performed and act in accordance with the recommendations received in response to the CLO.

Fill out the AGO for the work performed with a description of the reasons for the non-compliance and using the defect code, 1601130-051-001 “Vibration, jerking when starting a car with AMT”

, with attachment of a photo of error codes or 0
“Vehicle vibration when starting off”
, depending on the vehicle configuration, defective part 1601130, labor intensity item in accordance with the current collection of labor intensity.

Clutch failure

Often, jerking and jerking of the car when starting off occurs due to a clutch malfunction.

What may be faulty in the clutch mechanism:

The driven disk is worn out (replace only).
The disc hub is stuck on the transmission input shaft. The splines need to be cleaned. If this does not help, then replace the shaft or disk.
The linings are worn out or their fastening is loose. The driven disk assembly is replaced.
Window wear, broken or weakened springs. Disk replacement.
Spring plates reduced elasticity. The driven disk must be replaced with a new one.
The pressure plate or flywheel is scored. The clutch basket or flywheel needs to be replaced.

It is convenient to carry out repairs in a pit by lifting the front of the car. First, the starter, cardan and other parts are removed, depending on the design. After removing the gearbox, you can get to the clutch. Next, you need to remove the basket cover, flywheel parts, install a new disk and reassemble in reverse order.

Vibration that occurs after replacing clutch elements

There are few reasons why vibration occurs after replacing a clutch. Vibration usually appears in two forms:

The pressure plate (clutch basket) is not balanced;
During assembly, the driveshaft was installed in a different position from the original installation (but this only applies to rear-wheel drive or all-wheel drive vehicles).

By and large, on cars with front-wheel drive, you can inaccurately secure the wheel drive (CV joint), and the movement of the car will be accompanied by vibration and knocking, but this does not happen often.

If the clutch basket creates vibration, you can try moving it to a different position. As a rule, the pressure plate mounts are symmetrical. On many models, the basket is attached to the flywheel with six bolts, and the basket can be placed in three positions. In one position the vibration may disappear completely or be minimal. But it is better to exchange the warranty part immediately for another one. This will be less hassle for the car owner.

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Steering

The steering force is transmitted to the front wheels using a special device - the steering rack. If it is faulty, then when moving away the car may jerk, and there will be vibration on the steering wheel.

When the steering tips are worn, the front wheels create jerks when braking, accelerating or starting. The steering parts must be replaced with new ones.

Why does the car jerk when starting from a stop?

A machine is a complex mechanism that copes with enormous loads during operation. Therefore, you should not be particularly upset if any node fails or does not work as it should. Any car breaks down - it's only a matter of time. Drivers often complain on forums that their car jerks when starting from a stop. The reasons for this phenomenon may be different. Let's try to figure them out.

User manual

The vehicle's owner's manual contains a description of this system, as well as short instructions on how to use it:

The car is equipped with a system that keeps the car in place from rolling on a slope for 2-3 seconds. The system also operates on a slope when reversing uphill.

When stopping on an incline greater than 4%, depress the brake pedal with sufficient force to keep the vehicle stationary. When you subsequently release the brake pedal and press the accelerator pedal, the HHC function maintains hydraulic pressure in the brakes until the vehicle starts, but for no more than 2 seconds, which prevents the vehicle from rolling away.

The operation of the HHC is accompanied by a characteristic noise of the actuators. HHC does not operate when the parking brake is applied, the driver's door is open, or the ESC malfunctions.

How the anti-recoil system works on a Lada Vesta in the video:

Riding style

Speaking about why the car jerks when starting from a stop, we need to start with the obvious. The very first and most obvious reason is a harsh clutch. If you start, add gas and suddenly release the clutch pedal, the car will definitely jerk. Therefore, first of all, you need to try to change your driving style. At a minimum, when starting off, you need to release the clutch pedal very slowly and add a little more gas. However, you shouldn't press the gas pedal too hard.

However, if with an automatic transmission the car jerks when starting, then you won’t be able to change your driving style here, because there is simply no clutch pedal. But even with a manual transmission, the problem may be different. If the car still jerks even when starting smoothly, the problem is clearly not a sudden grip of the clutch discs.

Developments from different manufacturers

When looking for a car, not everyone makes having an HSA a top priority. At the same time, car enthusiasts are clearly not against having such an assistant in their car.

But sometimes, when studying the package, the buyer is somewhat disappointed when he does not see the HSA abbreviation in the list of components. Don't jump to conclusions. It's just that different car companies have their own names. Eg:

HAC or HSA. You will see a similar designation on cars from the Japanese automaker Toyota. Similar abbreviations are used on Lexus vehicles;
HHC. The German automaker Volkswagen uses its development, but uses a different name. It stands for Hill Hold Control. The name is different, the essence is the same;
H.H. The Hill Holder system under this name is installed on the model range of two brands simultaneously. These are the Italian Fiat and the Japanese Subaru;
USS. The Nissan company even applies the concept of Uphill Start Support.

If you notice abbreviations like HSA, HLA or HAC, it is worth checking with the specific manufacturer's manual to find out what this means. Almost certainly we are talking about a hill start assistant.

External and internal CV joints

If some suspension parts are poorly secured, then when driving (especially during a sharp start), they can cause the car to jerk. First of all, you need to check the inner and outer CV joints. The inner CV joint transmits rotational energy from the gearbox to the axle shafts and then to the wheels. This element is quite important, and if problems arise with it, it must be changed. This can be done at any service station. Features of failure of the inner CV joint are as follows:

When destroyed, the inner CV joint becomes loose and can turn when transmitting forces, especially at the start.
On a straight road without the smallest potholes, the inner CV joint can knock. In this case, it will seem that a dull knock is coming from the wheels.
Outer CV joints may crunch when turning. If destroyed, they can also cause the car to jerk when starting off.
Usually, internal CV joints simply wear out and because of this they fail. However, rarely the gearbox can cause a breakdown of this unit. This happens in cases where there is something wrong with the box itself.
Outer CV joints can break due to impacts or careless driving on a bad road.

If your VAZ car jerks when starting from a stop, then first of all you need to check the CV joints. Often on forums when discussing a similar problem, users point to this particular node. Considering the prevalence of these cars and the cheapness of spare parts, repairing this element is unlikely to be expensive. It is worth noting that a similar problem occurs on the VAZ-2114 car. When starting off, the car jerks, but after replacing the CV joint (“grenade”), the problem disappears.

Checking VAZ-2107

Now let's take a closer look at how to identify the cause of such a malfunction on different car models.

The first will be the carburetor VAZ-2107; there are plenty of cases when the car suddenly starts to jerk while driving.

First you need to inspect all pipes of the system for cracks;
Open the tank. It happens that in the summer the lid fits very tightly to the neck, blocking the access of air to the tank. When moving, the pump works and creates a vacuum in the tank, due to which the same pump is then unable to “pull” fuel. It seems like a small thing, but this also happens;
Inspect the fuel filter located in the pipes leading to the fuel pump. These filters are transparent and easy to visually evaluate;
You can also check the fuel pump without removing it. It is necessary to disconnect the pipeline coming from the pump from the carburetor and lower its end into some container. Then manually pump the pump into action and evaluate how it pumps fuel - it should supply it in even portions;
While the fuel pipe is disconnected from the carburetor, unscrew the fitting on which the fuel line fits and remove the small mesh filter, clean it and reinstall it;
Next comes the carburetor. It is advisable to remove it from the car, rinse it thoroughly, and inspect the accelerator pump membrane.

If actions with the fuel system did not help, we proceed to checking the ignition system.

We unscrew the spark plugs, check their functionality, and replace them if necessary; We check the system wiring for breakdown. This can be done this way - in the dark or in a closed garage (the main thing is that it is dark), open the hood and start the engine. If there are voltage losses on the wiring, they will be immediately noticeable by the sparks that form. Next, we replace the wiring that “breaks through” and check the wire connections; Next, we check the distributor, there should be no signs of critical wear, it should be dry under the cover. Be sure to inspect the centrifugal regulator, and also check the vacuum regulator. You should check whether there is a vacuum in the pipe leading to it. Then the Hall sensor, coil and switch will be checked for functionality. You can do this yourself if you have the necessary equipment at hand, but you need to know how to check them. But you can contact an auto electrician

It is also important not to forget to check that the ignition is installed correctly

This is in general and all the features of identifying the cause of uneven running on the VAZ-2107.

Transmission problem

The gearbox may well be the reason why the car jerks when starting off. However, there should also be other signs of a gearbox malfunction: difficulty shifting all or any one gear, a strange sound from this unit, etc. If this happens on the “mechanics”, then the problem is not so bad. In this case, the box itself can be repaired, and due to the simplicity of its design, repairs will not be so expensive. But if this problem is in the automatic transmission, then this is already serious.

The car jerks in first gear or second speed: fault diagnosis

As mentioned above, in such a situation, the first step is to gradually eliminate problems in the power supply system, ignition, as well as failures in the ECM. For example, a common reason when the car jerks at low speeds when engaging first and/or second gear is insufficient fuel/air supply to the engine or impaired mixture formation.

Various ECM sensors (Hall sensor, TPS, mass air flow sensor, etc.) can also malfunction. If everything is fine with the sensors, then you need to check the engine ECU. Quite often, the problem of jerking in 1st-2nd gear is directly related to the ignition. It is necessary to check the condition of the spark plugs and high-voltage wires, distributor and other elements on a particular machine.

As a rule, if the car drives jerkily, in relation to injection cars, specialists conduct comprehensive computer diagnostics of the engine. If such a check does not produce results or the cause is not found, then the vehicle’s transmission deserves special attention.

So, if your car is noticeably jerky in 1st and/or 2nd gear, it is important to understand that the transmission may also be causing the car to jerk when driving. At the same time, it is easier to determine the cause in the case of a manual transmission, while various types of automatic transmissions require more serious checks.

Let's start with the manual transmission. Please note that if an inexperienced driver's car jerks in first gear when starting off, it should be taken into account that often beginners simply make mistakes when releasing the clutch, while the car itself is working properly.

To start without jerking, you need to smoothly release the clutch before the driver feels the grip point (the beginning of the transmission of torque from the engine to the wheels). After the force begins to be transmitted to the wheels and the car begins to move, you need to carefully add gas, dosing the traction with the pedal accelerator.

But jerking is usually caused by problems with the clutch on the manual transmission or its adjustments. For example, a car jerks in first and second when the clutch driven disc is badly worn, the clutch does not “close” completely, and slips. This leads to the car jerking when changing gears.

In this case, jerks most often appear precisely in “low” gears (first, second speed), when the smoothest possible operation of the clutch is needed and at the same time, through the clutch in these gears, a sufficiently large torque is transmitted from the internal combustion engine to the gearbox when accelerating the car.

Now let's move on to automatic transmissions. First of all, you need to take into account that the quality of operation and smoothness of automatic transmission shifts will depend on the type of automatic transmission.

First of all, jerking can occur when driving with robotic gearboxes that have both one and two clutches. The fact is that the clutch of such gearboxes resembles in its design and principle of operation a conventional friction clutch of a manual transmission. Often the solution to the problem is to replace the DSG or AMT clutch, after which it is imperative to adapt the clutch (training, setting the grip point).

Also, in some cases, the culprit that the car jerks when driving in 1-2 gears may be breakdowns and malfunctions in the actuators that are responsible for the operation of the clutch in automated mode.

It should also be noted that the automatic transmission itself can “slip”, and the quality of its operation greatly depends on the level/condition of the transmission oil (ATF fluid). Jerking in automatic transmissions of this type may occur due to insufficient or overfilled oil, the use of a lubricant with unsuitable properties, etc.

Do they repair gearboxes?

In any case, you will have to go to a service station, where they will examine the car and issue a conclusion. If the automation fails, repairs will be quite expensive. However, if any gear from the mechanism breaks down, the box, in principle, can be disassembled and a separate element replaced, but this is also a rather painstaking and complex procedure, and it costs money.

Note that quite often service stations do not undertake to repair automatic transmissions at all. Often they are simply replaced, but there are craftsmen who agree to restore these units, which allows the owner to save money.

Steering gear

If the steering mechanism is faulty, a similar problem can also occur. If the steering rack has any malfunction, it can create jerks when starting. In this case, the worn parts of the rack are simply replaced, and the problem disappears.

Also, the steering rack tips may have strong play. As a result, during a sharp start or braking, or increase in speed, so-called steering wheel wobble may occur. Bent tie rods result in a sharp jerk of the steering wheel to one side when starting off. This problem requires a quick solution.

Other elements of the steering system, including bushings and silent blocks, can cause the car to knock and jerk when driving. All this applies to the steering mechanism - it can be the reason why, for example, a GAZelle car jerks when starting off. But GAZelle is not the only brand where such breakdowns occur.

Note that problems with the steering mechanism are easier to solve than problems with the automatic transmission. However, the steering mechanism requires urgent repair for the safety of the driver and passengers.

Let's sum it up

It is very difficult to say unequivocally why jerks occur when the car starts to move. Sometimes this turns out to be a consequence of problems in the chassis and suspension. Otherwise, the culprits are the engine and gearbox. Sometimes it turns out that the steering system is to blame for these troubles. The mechanisms in modern cars are quite complex; they require high-quality maintenance and regular diagnostics. Each of the components listed above must be repaired in a timely manner if certain breakdowns and troubles occur in the vehicle.

If timely repairs are not provided, the system may completely fail and become simply uncontrollable. Jerks, jolts, shaking and vibration appear. It is better not to allow such problems to occur in the car. If you go to a service station on time and carry out detailed diagnostics of the vehicle, you will be able to find out the cause and fix the problem at a time when it has not yet caused difficulties in operating the car. You should not delay replacing suspension or gearbox parts - this can lead to even more serious damage. Have you ever had your car jerk when starting to move?

Engine

As sad as it is to admit, a problem with the engine also occurs when such problems occur in the operation of the car. If there is really something wrong with the engine, its speed should jump during sudden jerks. The engine itself can live its own life and respond weakly to the gas pedal.

What could cause the engine to run like this:

Wear of friction pairs, which requires major repairs. This requires a lot of investment.
Crankshaft wear. In this case, the car should not only start to move jerkily, but also make noise and knock from the engine.
Engine coking. In this case, decarbonization will be required, which can be done at a service station.

Note that engine-related problems are the most unpleasant and most often require a large investment.

Defects that appeared after replacing the clutch

What does it mean to replace the clutch? This action means changing the driven or driven clutch disc; often both parts are changed at once. In this case, the release bearing must also be replaced. After such an operation, side defects are suddenly revealed that were not there before the repair.

If we think logically, then there are few reasons for the appearance of new malfunctions. Typically this is:

Unqualified repairs;
Defect of new spare parts;
Erroneous diagnostics, as a result of which not all or the wrong parts were replaced, and previously hidden problems manifested themselves in full.

In general, the issue of the appearance of new unpleasant signs is very difficult and is individual in each specific case, but these signs have common characteristic features.

Fuel system

If the fuel mixture is supplied to the combustion chambers of the engine in the wrong amount, jerking may occur when driving. This can happen if the car owner fills the tank with poor quality fuel or gasoline that the car is not designed for. For example, if a Euro-4 or Euro-5 engine is supplied with fuel with a high sulfur content (92 gasoline), it will wear out quickly. Some injectors may also become clogged, causing the wrong amount of fuel to be delivered. This can lead to jerking at start, but the “symptoms” can be different: loss of power, detonation, increased gas consumption.

Problems with other elements

Quite often, Opel cars jerk when starting from a stop due to problems with the exhaust gas recirculation valve. This valve is a headache for many Opel owners with Ecotec engines. As a result of the formation of soot on the valve, it may simply become clogged, and then an incomprehensible mixture consisting of fuel, air and waste exhaust gases will enter the combustion chambers. This is fraught with loss of power, increased consumption and, possibly, jerks at start.

Therefore, it is very important to fill only high-quality gasoline, and not save on buying fuel suitable for your engine. The same can be said about oil. Under no circumstances should you fill in oil with the wrong viscosity or additives!

"Brains" of the car

A special program decides in what proportion to mix fuel with air and feed it into the combustion chambers. If the program makes an error, then the engine will receive a mixture with an incorrect air/gasoline ratio, which can also cause the car to jerk when starting off. An oversaturated or undersaturated mixture may be fed into the combustion chambers, then a batch of normal mixture may enter the system, after which improper mixing occurs again - all of which can easily cause the car to jerk, both when starting and when driving at speed. This may also be accompanied by popping noises from the exhaust pipe or lack of engine response to the gas pedal.

What to do

Why won't my car start from auto start? overview of reasons

If the engine jerks at idle, the cause should initially be determined. Then replace the damaged unit.

For carburetor models, the primary diagnosis begins with the throttle and the combustible mixture formation unit itself. Usually on old foreign cars and VAZs the root of evil is located here.

If the problem arose on a modern VAZ 2114/15 or on an “exotic” model like 1JZ-GE. The source of the problem may be inside the sensors. First of all, the DPKV, temperature sensor, temperature control system and others are checked. If everything is in order, you need to move on. High-voltage wires, spark plugs, and the ECM are diagnosed, and the ECU is checked last.

The car jerks at idle and when driving

If the problem occurs not only while parked, but also while driving, it is necessary to check the ignition, carburetor, and serviceability of the throttle valve.

For the injector, diagnostics of the fuel rail, its pressure, tightness, and the condition of the injectors are appropriate.

Also in both cases, the electronic part is diagnosed: control units, distributor, wiring, spark plugs.

The malfunction is caused by a failure, incorrect operation, of one of the vehicle systems.

The injector jerks

Main reasons:

injectors or individual fuel supply elements are clogged;
ignition coils are not working properly;
The ECU and sensors are not functioning correctly.

The carburetor jerks

Everything is simpler with a carburetor. Here's what you should check:

throttle valve condition;
filters;
spark plugs;
distributor;
Is the fuel pump working correctly?

At idle the car jerks and stalls

If the engine does not idle during a cold start in winter, there is nothing terrible - the block will warm up and everything will return to normal. However, if there is a failure after warming up, there may be several reasons for the breakdown.

Idle air control failure.
Clogged, throttle malfunction.
The carburetor and jets are clogged (the injectors are checked for the injector).
The fuel supply pump is faulty.
The air/fuel filter is worn out.
Failure of the electronic sensor MRV, TPS, DPKV.

The car shakes at idle

If vibration is transmitted to the car body, the first step is to check the wear of the power plant mounts. Squashed cushions do not reliably hold the engine in place, which causes severe shaking, deviation of the internal combustion engine from the nominal position and, as a result, vibration.

Other causes of shaking are described above.

The car shakes and jerks at idle

The process of engine tripping is a consequence of the malfunction of one or more cylinders. A similar breakdown is caused by a failure of the spark plug or a breakdown of the high-voltage wire.

With the engine running, remove the spark plug cap from the first cylinder.
After 3-4 seconds, install the element in place.
Consistently repeat the procedure for all boilers.

During the check, you must listen to the sound of the engine. If the growling gets worse (the system doubles), the compartment is fine. If the result is neutral (nothing has changed), it is worth checking the line completely for serviceability.

The primary source of failure may be the following reasons:

incorrect mixture setting - the cylinder floods;
spark plug or wiring is of poor quality;
occurrence of rings;
piston wear.

Diesel car jerks at idle

There can be only three reasons here.

The cylinder compression has dropped. As a rule, this occurs due to burnout of the cylinder head gasket and wear of the piston group elements.
Injector problems - poor mixture supply, blockages, intake failure.
Malfunction of the injection pump.

The car on gas jerks at idle

If a breakdown is detected, it is strictly not recommended to interfere with the unit yourself. You must contact a qualified gas fitter.

Interruptions on a cold engine

If the engine stalls at idle and then levels out after warming up, don’t worry too much. When cold, the power plant does not have normal clearances and can operate unstably. After reaching the design temperature, the motor stabilizes and stops twitching.

If the vibrations are strong and prolonged

When vibration in the engine does not disappear, but persists for a long time, this may indicate problems:

wear of the piston group;
violation of internal combustion engine fasteners;
incorrect operation of the fuel system;
ignition problems.

How to prevent this?

The following tips are a little banal, but effective. At a minimum, you need to fill your car with high-quality gasoline with the correct octane number. The instructions for the car must indicate what fuel should be poured into the tank.

This also applies to oil. It is necessary to use only the lubricant recommended by the manufacturer. Taking into account the presence of counterfeit oils on the market and low quality fuel, it is necessary to change oils even more often than the car manufacturer recommends. At a minimum, after 8-9 thousand kilometers the lubricant must be replaced. This will extend the life of the motor.

In general, you need to operate the car carefully. If you put a heavy load on the engine at least once and heat it up to the “red zone” on the thermometer, then problems with the engine can arise constantly. In this case, jerking when starting is far from the worst problem.

Another reason for the growls

When you turn on the automatic transmission, the car jerks: the main reasons
The same jerks can appear after refueling with low-octane gasoline. On carburetor engines, the advance angle is set manually and is practically fixed. For normal operation of the engine on gasoline with a lower octane number, it will be necessary to install a “later” ignition.

The owner of a carburetor VAZ 21099 with LPG may encounter this problem. If for some reason he cannot fill the gas and is forced to drive on gasoline, then he has to change the advance angle setting. This is explained by the large difference in the octane numbers of propane and gasoline (for gas it is more than 100).