When you press the gas pedal, the car jerks. The car twitches while driving: what could be the reason

Many owners of cars, both domestic and foreign, often face the problem of car jerks when the gas pedal is pressed. There are many reasons for this behavior. Therefore, we suggest that you further familiarize yourself with the most common malfunctions that cause such jerks, as well as their symptoms and solutions.

1 Malfunction of fuel system sensors

A common cause of jerks when the gas pedal is pressed is a malfunction of the TPS, especially this often happens with "VAZ" models. This sensor determines the position throttle valve. It is quite simple to identify its malfunction, thanks to a characteristic symptom - the car starts to “jump” during acceleration, even if the gas pedal is pressed very smoothly.

Most often, as a result of a TPS malfunction, the throttle valve remains in an ajar position for a long time. When you press the gas pedal, the sensor does not immediately transmit a signal to the computer. As a result, the engine at first cannot change the mode of operation, and then the fuel is supplied abruptly and in large volumes. As a result, the engine begins to “choke” and work jerkily, and sometimes it stalls altogether.

There is only one way to solve the problem - change the sensor. True, some car services offer controller repair. But, as practice shows, a repaired TPS serves no more than one or two months. So it's better to buy new part. In the photo above you see the location of the TPS in a VAZ 2114 car.

Another sensor that, when it fails, causes the car to twitch is the air flow sensor (DMRV). In the event of a breakdown, the engine starts to work unstably at any pressure on the gas. As in the previous case, the problem is solved by replacing the sensor. Sometimes the problem is not the sensor itself, but the air duct (corrugation) that goes from the air filter to the engine. As a result of its depressurization, air leakage can be carried out bypassing the sensor, which causes malfunctions in its operation.

For some cars, jerking when picking up speed at idle can occur as a result of a failure of the crankshaft position sensor (DPKV), which is located near the oil pump. The photo below shows the location of the DPKV of a Priora car with an engine of 21126, i.e. having 16 valves.

To check the operation of this controller, you need to connect an oscilloscope to it. Smeared or barely noticeable pulses indicate that the sensor is really not working correctly. Please note that if it is completely out of order, the car generally stops starting.

2 Problems in the fuel supply system

Often the car starts to twitch when starting off and picking up speed as a result of a lack of fuel in the float chamber. Most often, the malfunction manifests itself when you sharply press the gas. This is due to the fact that the fuel is burned in the engine much faster than it enters the float chamber.

There are several reasons why this situation may arise. Typically, fuel interruptions occur as a result of a malfunctioning fuel pump. To resolve this issue, you can follow these steps:

Remove the pump cover.
Examine the surface of the lid. Replace sealing ring if necessary.
If chamber depressurization or other fuel injection problems are found, worn parts must be replaced.

Most often, the fuel pump is located under the hood. However, some vehicles may have it at the rear. For example, in the VAZ 2110 and VAZ 2112 models, to access the fuel pump, you need to dismantle backseat and unscrew the cover, as shown in the photo below.

Sometimes the cause of all problems in the fuel supply system is banal - clogged fuel filter. If it is not replaced in time, it can become so clogged that the fuel supply stops altogether and it will be impossible to start the car.

3 Malfunction in the mixture preparation unit

If the car is dull when picking up speed and starts to twitch when the gas pedal is pressed sharply, it is quite possible that the malfunction lies in the mixture preparation unit, i.e. carburetor or injector. Most often this occurs as a result of clogged jets, air channels or nozzles. Car owners usually face a similar situation in the spring, after a long idle time of the car or after filling low-quality fuel.

In some carbureted cars, for example, VAZ 2109, you can correct the situation without even removing the carburetor. To do this, you just need to dismantle the air filter located above the carburetor, and then blow through all the channels with a hand pump with a cone tip. It is advisable to do the work together, so that one person puts the tip to the channels and holds it, and the second one works with the pump with sharp and powerful movements.

Of course, such manipulations will not give a 100% result, and besides, the situation will improve for a short time. But if the problem happened on the road, purging with a pump can really help out. For normal cleaning, you must contact the service center, where specialists will wash the carburetor special tool. The situation is exactly the same with the injector: blockages can only be eliminated by flushing. Moreover, for this it is necessary to use a special tool for injectors.

It must be carried out on a special stand that simulates the operation of the engine, so it is impossible to do it yourself.

4 We are looking for a reason in the electrician

Very often, the cause of the car jerking and slow revving is the “trimming” of the engine due to problems in the ignition system. In this case, when you gently press the gas pedal, the problem is often not noticeable at all, but when you press it hard, the engine seems to "choke". On the high revs"Trimming" may also not be felt. In motion, jerks can occur only at certain speeds or when the car is moving up a hill.

Most often, in such a situation, replacing candles helps. However, the problem is not always in candles. Often, "trimming" occurs due to problems with high-voltage wires that go from the distributor to the candles. You can identify a faulty wire by simply listening to the wiring with the engine running. A wire that has a "breakdown" makes a characteristic clicking sound. In the dark, you can even see a spark. True, in some cases, the wires fail asymptomatically, therefore, it is possible to identify a faulty element only by replacing the wires one by one.

Sometimes it’s not even the wires themselves that cause the problem, but the tips on the coils and candles. Accordingly, it is easily solved by replacing the tips.

That's all the common reasons why the car starts to twitch when you sharply or even smoothly press the gas pedal with your foot. If, after performing all the above steps, you could not fix the problem, contact the service center, where specialists will perform computer diagnostics and pinpoint the cause of the problem. It is often possible to get rid of jerks only after flashing the on-board computer.

A car malfunction can manifest itself in different ways, most often it is foreign noises, such as knocking or creaking. But, sometimes malfunctions have more noticeable symptoms, for example, the car may deviate from the course set by the driver or twitch when accelerating and gaining speed. In this article, we will consider the latter option, namely why the car twitches during acceleration and what to do in such a situation.

All currently operated cars with gasoline engines are equipped with either injection or carburetor power units. The second type of internal combustion engine is now considered almost "rare", but in Russia (especially in the provinces) there are still a lot of such equipment "on the go". Therefore consideration possible causes, along which passenger cars can twitch and accelerate jerkily, it makes sense to start with them.

Carburetor engines

These power units, in comparison with more modern, injection ones, are simpler in design, all of them " weak spots”are well studied, and therefore it is not so difficult to find the reason for their unstable operation at the stage of starting and accelerating the car. Experienced motorists with knowledge of the matter claim that cars with a carburetor engine most often twitch due to such problems as:

Dirty fuel or air filter;
Problems in the operation of the fuel pump;
Fuel pressure regulator malfunction.

Thus, those owners of cars with carburetor engines, whose cars began to twitch when the engine was started and accelerated, should, first of all, check exactly those parts, components and assemblies that are listed above.

If it turns out that everything is in order with them, then you need to pay close attention to the ignition system. In carburetor engines, its malfunctions are also often the causes of jerks. Practice shows that in those cases when, when the accelerator pedal is pressed, the car refuses to accelerate (as drivers say in their professional slang, “fails”), it makes sense to check the ignition coil well, as well as those connected to it high voltage wires.

In fact, quite often it turns out that these parts begin to “break through”, and therefore the engine “troit”. The solution to the problem in this case is to replace the defective part.

Another fairly common problem is the banal soot in candles. It leads to the fact that the spark does not occur when it should (and sometimes does not occur at all), which leads to jerks during acceleration. The way out of this situation is to clean or replace the spark plugs.

injection engines

Gasoline power units of this type have significantly better operational and specifications, but their design is much more complicated. Accordingly, there are much more reasons due to which the car can twitch during acceleration.

The main feature of the injection motor is that by adjusting the feed fuel mixture in his combustion chamber is engaged in a special the electronic unit. Several sensors are involved in this process, namely:

Throttle positions;
mass air flow;
Regulations crankshaft.

A malfunction of any of them can cause the car to twitch when starting the engine and accelerating. It is interesting, however, that when serious problems with crankshaft position sensor injection system often turns off completely, and then it is impossible to start the engine at all.

It goes without saying that the causes of jerking during acceleration of cars equipped with injection engines can be the same as for carburetor engines, that is, filter blockages, problems with spark plugs, ignition coils and high-voltage wires, as well as elements fuel system(including clogged fuel injectors).

It should also be noted that one of the common causes of car jerking when starting the engine and accelerating is the use of low-quality fuel. As a result, a lean fuel mixture is formed, and the engine starts to work very unstable, in particular, jerks appear during acceleration. This applies equally to both carburetor and injection power units.

What to do if the car jerks during acceleration?

In order to accurately diagnose the cause of unstable operation gasoline engine internal combustion, expressed in jerking during startup and acceleration, first of all, you need to make sure exactly what is used quality fuel. It is necessary to check its density, octane number (corresponding devices are now sold in specialized stores and are very inexpensive). If it turns out that the cause of jerks during acceleration is precisely bad fuel, then it simply does not need to be used.

You should also check the air and fuel filters. That they are contaminated is usually visible to the naked eye. The remedy is to replace these consumables with new ones.

To check the candles, you just need to remove them and subject them to a visual inspection. If it turns out that they have soot, then it should be removed or simply replaced with new candles. As for coils and high-voltage wires, the most common cause of their failure is the oxidation of contacts. To identify it, the easiest way is to use a multimeter and "ring out" the circuit. Faulty ignition coils and high-voltage wires should not be repaired, but replaced with new ones entirely.

As for the sensors in injection engines, a conventional oscilloscope is used to check them. If this component is working, then pulses are displayed on the screen, indicating the operation of the injector. In cases where there are none or they have an irregular shape, the sensors should be replaced with new ones.

Video about jerking during acceleration

The car can be faced with the fact that the engine twitches during acceleration. In other words, after a sharp press on the gas pedal, there is no clear response from power unit, there is a pause-failure, a set of revolutions occurs in jerks, etc.

These jerks are a rapid change in the crankshaft speed, regardless of the position of the gas pedal and the degree of depression on the accelerator. As a rule, such jerks follow in series, causing the engine to twitch.

As for the failure, that is, when the engine “dulls” during acceleration, there is a noticeable delay in the reactions of the internal combustion engine after the driver has sharply pressed the gas to increase speed. Moreover, in both cases, during a smooth press on the gas pedal, the speed increase occurs without jerks and delays, that is, it is quite predictable.

It is quite obvious that the operation of a vehicle with such malfunctions is not only difficult, but also dangerous. While driving, there is no way to overtake, change lanes quickly, etc. To solve the problem, the engine needs in-depth diagnostics, since it is first necessary to clearly determine the cause of the breakdown.

Read in this article

Why the engine twitches during acceleration: the main reasons

To begin with, most of the reasons why such deviations in the operation of the internal combustion engine occur are often associated with the following systems:

Air suction and sensors

As you know, the injection engine is equipped with, which fully controls the operation of the power unit. The specified system is actually numerous sensors and a controller (ECU). Based on the readings of the sensors, the control unit corrects the UOZ, increases or decreases the amount of fuel supplied, prepares the fuel-air mixture that will be optimal for a particular engine operation mode, etc.

So, the engine may twitch if there are problems with. Normally, when you sharply press the accelerator pedal, the sensor sends a signal to the ECU that the damper is wide open and you need to increase the fuel supply.

If the signal is incorrect, then the fuel supply may not be implemented correctly. In this case, a failure occurs, which the driver feels in the form of a delay in pressing the gas, that is, a failure. Note that such failures are especially relevant on those cars where the gas pedal is “electronic”. In other words, there is no direct connection to the throttle assembly.

We also add that the throttle valve must be cleaned periodically, and on many cars it is required to carry out the procedure after cleaning this element. To avoid problems, experienced drivers clean the throttle at least once a year. This procedure is performed for preventive purposes.

Also in the list of sensors that can cause the motor to twitch during acceleration is the position sensor camshaft DPRV and mass air flow sensor, known as. For an accurate determination, it is recommended to conduct a car, which in many cases allows you to read errors from the ECU memory and identify malfunctions in the sensors.

IN garage conditions when there is no diagnostic equipment, the check of electronic sensors is carried out by the elimination method, a tester-multimeter is used for diagnostics.

As for air leakage, such a phenomenon may well lead to jerks and dips during acceleration. If excess air is sucked in somewhere, then the ECU loses the ability to correctly determine its amount entering the motor.

As a result, the mixture of fuel and air will be prepared incorrectly, instead of a powerful “rich” mixture, a lean working mixture will be supplied to the cylinders. Leakage can occur on, there may also be problems in the fuel supply system. In any case, depressurization requires immediate detection of the problem area.

What is the result

As you can see, the engine can twitch during acceleration for a number of reasons. If the replacement of “consumables” (spark plugs, armored wires, filters), as well as standard planned procedures (cleaning the injector, setting the carburetor, setting the UOZ, etc.) do not give results, then the chain also follows, that is, the installation of the valve timing.

Also a frequent case is such a situation when the engine roars during acceleration, while the car does not accelerate, jolts, jerks or bumps are felt. As a rule, malfunctions of this kind are not associated with the internal combustion engine and its systems, but with the transmission. Often, malfunctions of automatic transmissions (automatic transmission) appear this way, but one should not exclude a problematic clutch on ordinary “mechanics”.

In such a situation, an urgent diagnosis of the gearbox is necessary. FROM manual transmission it’s easier to figure it out by replacing the clutch disc, basket or the entire assembly. On machines with a classic torque converter automatic transmission or manual transmission ( robotic box gear shifting) when jerks appear, it is necessary to stop using the vehicle.

Then you need to check the oil level in the automatic box and its condition. Next, you will need to diagnose electronic components, actuators, etc. You also need to be prepared for the fact that the box (as a rule, this applies to automatic transmissions) in many cases will need to be disassembled for troubleshooting and subsequent expensive repairs.

Causes of failure during acceleration

gas wiring;
Bad weight.

If the tips above did not help, only diagnostics will solve the cause of this behavior of the gas pedal. Incorrect operation of systems, errors, composition of the fuel mixture - the diagnostician will name a specific malfunction.

Even with good work engine, the vehicle may jerk when accelerating. Motors that meet Euro-4 and higher environmental standards have such an unpleasant property. The point is the reaction of the electronic throttle to pressing the gas pedal. It is non-linear for the first 3-4 centimeters of travel. Because of this, a failure may occur during acceleration.

Smoother shifting;

Car owners often notice that the car twitches during acceleration. Such failures mainly appear at low and medium speeds. They are characterized as follows:

A dip of 2 to 9 seconds;
Jerk in 1-2 seconds;
Twitching - a series of jerks;
Rocking - a series of failures.

Few people like this behavior of the car. If the car is dull during acceleration, you have to press the pedal harder, which increases fuel consumption. This is also a safety issue for the driver and passengers. When overtaking, a quick reaction to the gas is necessary, but the car "thinks for a long time", which is why you may not have time to complete the maneuver. With such thoughtfulness of the gas pedal, the ride becomes uncomfortable.

Causes of failure during acceleration

You can determine the reason why the car is twitching using diagnostics. Possible problems:

On HBO, the problem may arise due to:

Faulty HBO control unit;
Interference in the harness to which the fuel injectors are connected;
gas wiring;
Bad weight.

How to fix crashes when overclocking

Check wires and ignition coils. When broken, the spark plug wires spark and glow in the dark. The engine troit, jerking appears. This happens from "age", poor-quality parts or poor contact with candles. The malfunction may be related to the temperature of the engine. The interwinding resistance of the coils and the thermal mode of operation change together, which is why the car on gasoline twitches during acceleration.
If you have a diesel, jerks during acceleration are definitely not related to the operation of the coils, they are not there.
Examine the spark plugs. Poor contact with wires, strong soot, too lean or rich fuel mixture disable them. Unscrew and check each candle as in our article "Diagnosis of ICE Operation by Candles", where we gave examples of faulty candles.
Check fuel, oil and air filters. Over time, they become clogged, which leads to a deterioration in dynamics, an increase in fuel consumption and periodic failures. You can replace them yourself, they are inexpensive and easy to install.

Even with the engine running properly, the car may jerk when accelerating. Motors that meet Euro-4 and higher environmental standards have such an unpleasant property. The point is the reaction of the electronic throttle to pressing the gas pedal. It is non-linear for the first 3-4 centimeters of travel. Because of this, a failure may occur during acceleration.

Chip tuning to Euro-2 or Euro-0 standards improves the response of the gas pedal and solves the problem. ECU firmware has a number of other advantages:

Improves overall dynamics, idling and traction at low revs;
The car does not stop when the air conditioner is on;
Smoother shifting;
Reduces fuel consumption while maintaining driving style.

Video from our partner, how chip tuning copes with failures and "thoughtfulness" of the accelerator pedal on the Gazelle Next:

Contact ADACT partners in your city for chip tuning. We guarantee a 10-day test drive, money back and stock if you don't like the firmware.

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The most common problem that car owners may encounter is the sudden "jerking" of the car in different situations. For example, during acceleration, at low speed or at the very beginning of the movement. Those who have been driving for more than a dozen years do not focus on this at all. This is explained by the fact that these “symptoms” can be expressed in any car, and it doesn’t matter how old it is, what brand it is, how much experience its driver has.

Lada Desyatka, Hyundai Solaris, and any other car can "rush" from a place. But this is, in any case, a deviation from the norm of the engine. Therefore, at the first unpleasant situations, it is necessary to identify the cause and get rid of the problem. Because the longer you ignore this kind of movement, the more the entire repair will cost you.

A twitching car is not the most welcome participant traffic. In which case, you will definitely collect a couple of accidents in your piggy bank. Photo: desertoasisautorepair.com

By the way, you should not try to solve the problem on your own if you are not confident in your skills and abilities. Entrust the car to a knowledgeable and experienced workshop technician. Do it as soon as possible.

Why the car may start to twitch

So, if your car began to make “tearing” movements that were not characteristic of it and did not appear before, you should do:

Remember candles. Check their performance. Replace if necessary.
Check the wiring of the car, and in particular the ignition coil.
Check the injectors, they may be clogged and cause twitching.
Don't forget air and fuel filters.
If you have a carburetor, check the ignition timing
Check fuel pump. Perhaps because of it, gasoline is supplied unevenly
Check fuel pressure. Maybe it's just not enough power.

Possible causes, depending on the type of car engine, and their elimination will be discussed below.

If you have an injector

Jerking movements are common, especially if your car is more than three years old, and during this period it was actively exploited. Photo: 111.ural2.ru

The problem arises because when the engine is still cold or just starting to warm up, there is a sudden “drop” in speed, and the difference between the deviation and the norm is a fraction of a second. The number of revolutions varies from five hundred to one and a half thousand. Further, as the engine warms up more, the number of revolutions is normalized, dips and drops disappear and do not repeat until the next time, when the engine cools down again, and it will be put into action again. Such "tricks" can discourage even the most experienced motorist. And the reason for this action is just a sensor. Yes, temperature sensor.

How to solve this problem? Elementary: buying a new one and replacing the old one.

On the injector, such problems can also occur due to the fact that an electronic fuel injection system is installed on the engine. And the reason lies in the wrong flow of air. It all starts with the fact that the control unit incorrectly calculates the required amount of air to enter. Air enters the cylinders, the injector valves open. And there is more air than necessary! Consequently, the throttle sensor is triggered, along with it the temperature sensor shows that the engine has already warmed up, and less gasoline needs to be spent. The computer has a "shock", he does not understand what to do with this very excess air.

If, when you sharply press the gas pedal, the car jerks forward, then the problem lies in clogged injection nozzles. It is treated by washing them out with a special agent under high pressure, or by ultrasound.

Also, the problem may lurk in the ignition system. Look for faults either in the wiring, or in the candles, or in the ignition coil. In any case, you will have to replace the non-working element.
Another cause could be a stuck crankcase ventilation valve.

If you have a carburetor

The jerking of the carburetor machine without any suspicious and incomprehensible sounds and rattles may indicate a malfunction or malfunction of the carburetor or ignition system itself.

In most cases, cars with this type of engine twitch precisely because of its clogging. Photo: cdn.klimg.com

What to do in this case? In no case do not self-will and do not self-made! Contact the master. He will clean the carburetor channels, the idling system, jets. Also, the specialist will properly check the carburetor, if there are any mechanical damage that may be the cause of jerky movements of the car, he will quickly fix them. One of these damages is the sticking of the throttle valve of the carburetor mixing chamber. In view of this, the engine cannot gain the power it needs and the car just simply starts to pull.

Don't forget the fuel filter. If it was replaced a long time ago or never at all, then the car jerks at low speeds due to the fact that little or practically no gasoline enters the fuel supply system at all.

There are other options for causes related to gasoline. For example, bad pump pumping gasoline. Because of this, the car “lives its own life”: it stalls, accelerates hard, twitches when switching gears. The solution to the problem is elementary: blow it out of dirt or replace it with a new one.

If the car jerks when accelerating, pay attention to this video:

If you have a diesel

FROM diesel engine everything is very clear. Firstly, such cars will twitch only at idle. Secondly, there is only one reason for jerks - stuck movable blades in the feed pump. And this happens because of a common disease of cars - rust. Only this rust is formed due to water that got along with the fuel. Where did she come from? From the street! Perhaps the car faithfully defended the rainy autumn and snowy winter on the street under the open sky. It is for this reason that cars are recommended to be put in garages for the winter or, at least, under sheds.

But, if not such an opportunity, and diesel car still have to stand on the street, it is necessary to pour special additives into the fuel. And auto mechanics from the northern regions recommend pouring into fuel tank some special motor oil.

Outcome

Even the most careful and thrifty driver is not immune from a car breakdown. This is influenced by many factors beyond the control of the driver. Build quality, reliability of installed parts, correct calculations of engineers, road conditions, period and intensity of operation, and even climatic conditions. But every car owner must maintain the working condition of the car. And if you stubbornly ignore his "complaints" and continue to ride, then you can finally "kill" him.

Of course, it will be possible to try to “reanimate” it, but this can cost a fairly tidy sum. Moreover, the reasons why the car can twitch lie on the surface. Candles, clutch, filters - small details leading to big problems. Take the time and some money to take your car in for diagnostics.

She needs it regularly, like a visit to the hospital. For proper care, the car will thank you for many years of faithful service!

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