The car jerks on the gas. Why does the car jerk on gas? Causes and remedies of malfunction When you press the gas, the injector jerks

Jerks during acceleration are an unpleasant and unsafe thing: this may not end well when overtaking. So, having found such symptoms, it is not worth delaying the search for the cause of the malfunction, especially since the basic diagnosis is not so difficult here.

The jerking itself (if the source of the problem lies in the engine and not in the automatic transmission) indicates a loss of power or massive misfires when the load is increased rapidly. More or less understanding the principles of ICE operation, a list of possible search directions can be made even empirically.

The reasons why the car jerks when accelerating

Ignition system malfunctions

So, the car jerks when accelerating. What happens when the driver presses the gas pedal? Engine rpm is relatively low and intake resistance affects cylinder filling. With a sharp opening of the throttle, the filling ratio (the ratio of the volume of air actually entering the cylinder to its geometric volume) approaches 100%, and the pressure at the end of the compression stroke reaches a maximum.

At this point, the conditions for a spark in the spark plugs deteriorate: the higher the pressure, the more difficult it is to break through the spark gap. At the same time, problems with the ignition system come out: the spark starts to "run away" over the carbon deposits on the electrodes, along the punctured tips, and so on. Breakdowns in the ignition coils, imperceptible by the uniformity of the idle, immediately betray themselves. Therefore, it is worth starting the diagnosis with the ignition system.

We examine the candles and their insulators. Carbon deposits should be:

On: white, or white with a reddish-brown impurity - the result of working on "environmentally friendly" mixtures.
On carburetor engines: in a range of reddish-brown shades.

The electrodes themselves should not have traces of erosion or melting, chips and cracks on insulators are unacceptable.

If not, try a new kit first. If the car still jerks when the gas pedal is pressed, we continue to check, otherwise we are looking for the cause of the spark plugs failure (for example, heavy dry carbon black - obvious problems with over-enrichment of the mixture).

On carburetor engines and injection engines without phased ignition, we then check the high-voltage wires (in garage conditions it is easier to use a new kit), the distributor (if any), the ignition coil. Motors with phased injection and individual ignition coils in the IKZ often have problems - cracks in the housings, moisture ingress into the spark plug wells due to dry seals.

There are exception motors, where the presence of individual ignition coils does not mean phased system operation. These are without phase sensors: their primary windings of coils 1-4 and 2-3 cylinders are connected in series, two coils are triggered at a time, and a malfunction of one will affect the operation of the second.

To help locate the source of problems, use a homemade spark gap by taking an inexpensive spark plug and increasing the electrode gap several times or removing the side electrode. We attach a piece of wire with a crocodile at the end to the candle skirt to ensure reliable contact with the ground.

This homemade spark gap places a high load on the ignition system, comparable to actual operating conditions, and can accurately indicate problems with the high voltage circuit of the ignition system.

Carburetor problems

In carburetor engines, normal mixture formation at the time of increasing the speed is disrupted due to a sharp drop in the vacuum in the diffuser. Therefore, to maintain efficiency, it is necessary to use a separate system that ensures the enrichment of the mixture during overgas - an accelerator pump. If the car jerks when accelerating, then the performance of the accelerating pump is impaired.

Let's consider its work using an example from front-wheel drive VAZs.

An eccentric cam is rigidly connected to the throttle axis of the first chamber, which presses the lever of the accelerating pump. He presses on the rod of the spring-loaded diaphragm. As soon as the driver sharply presses on the gas, pressing the diaphragm rod creates pressure under it. In this case, the ball valve in the channel connecting the cavity of the accelerating pump with the float chamber closes, and the fuel pressure opens the second valve in the channel leading to the atomizers. Under pressure, fuel is sprayed into the diffusers, enriching the mixture.

As soon as the gas is released, a spring, pushing out the diaphragm, creates a vacuum in the cavity. The valve in the nozzle channel closes, preventing air from sucking in through the nozzles. The vacuum opens the bottom valve, allowing the booster pump to refill with gasoline.

Therefore, if there is no normal acceleration, it is necessary to check the parts of the accelerating pump - the integrity of the diaphragm, the operation of the valves, and blow out the sprayer. Checking the pump's performance is simple - after removing the air filter, we sharply turn the gas cable sector on the carburetor. If the accelerating pump is in good working order, smooth jets of gasoline should hit from both nozzles.

Injection engine problems

The acceleration mode from the point of view of the "iron" of the injection system is no different from the other, in contrast to the carburetors. Then why does the car jerk on the move? There is insufficient fuel supply, which the ECM cannot compensate for by increasing the injector opening time.

In the acceleration mode, the momentary fuel consumption jumps to the maximum, so that things are revealed that are invisible with uniform movement. The first step is to replace the fine fuel filter if it has already traveled several thousand kilometers, and to measure the fuel pressure, not gassing on the spot, but under load. It should not fall below the nominal value for a particular vehicle by more than 0.1-0.2 bar.

The fuel pressure gauge is convenient when working with cars equipped with a drain rail: they have a fuel pressure regulator installed on the rail and controlled by the manifold vacuum. The fuel pressure in the rail is equal to the nominal pressure of the regulator calibration plus the manifold pressure (if the regulator is calibrated at 3 bar, and the manifold pressure is minus 0.5 bar, the pressure gauge will show 2.5 bar). When you press the gas, the fuel pressure jumps from a reduced one to the passport norm. Is the pressure rising weakly or not rising at all? Try to squeeze the return line: if the pump is working properly, and the pressure regulator bleeds, then the pressure rises. Otherwise, the pressure regulator will need to be replaced.

Something else useful for you:

On motors with a drainless ramp, to access the regulator, you will have to remove the fuel pump module. At the same time, the degree of contamination of the mesh at the inlet is immediately checked: at peak fuel consumption, dirt can already give a noticeable pressure drop. This will not be superfluous on engines with a drain ramp.

"Underfilling" can also be the result of clogged nozzles. If desired, check their real performance even in the garage by forcibly turning on the gas pump and applying 12 volts to the injector connector. The volume of fuel poured into a measuring vessel per minute will give us the required figure. At the same time, we also check the shape of the spray torch - it is clearly visible on it. But it's easier to go to the stand.

It is worth checking the operation of the position sensor: by changing the signal from it, the injection computer calculates the dynamics of changing the throttle position and, accordingly, adjusts the fuel supply for individual fuel cards. To do this, use a voltmeter (preferably a dial gauge, it has a much shorter response time) or a cheap diagnostic adapter such as ELM327. Turning on the ignition, smoothly press on the gas: the DPKV signal in the form of a voltage on the voltmeter or a percentage of throttle opening in the diagnostic program should grow just as smoothly, without dips and falls signaling a sensor malfunction.

The oscilloscope is easier and clearer. For example, here is a faulty TPS:

Instead of an even increase in the signal, we see sharp voltage surges in different directions. The injection computer with such a sensor will not be able to correctly calculate the enrichment of the mixture for acceleration. Hence the jerks. Moreover, if the car jerks to hot during acceleration, then suspicions of TPS even increase: the cold mixture is somewhat enriched, and this evens out the failures.

Automatic transmission malfunctions

Jerks and jerking of the car during acceleration, if it is equipped with an "automatic", give one more object for research. However, independently checking the operation of the valve body or clutches is not quite the level of garage diagnostics.

What remains for self-checking in the automatic transmission? First of all - the oil level, the hydromechanics is sensitive to it. It should be borne in mind that the level in most boxes is measured at a specific temperature and a running motor: check the procedure in the service documentation for your car.

In addition to the oil level, pay attention to its condition. Blackening, metallic gleams, a clear burning smell indicate problems with the box, which will only get worse in the future. It is worth immediately contacting specialists in order, if possible, to have time to get rid of the "little blood".

Seal

A working car is a guarantee of traffic safety on the road. However, unexpected disruptions while driving can cause special troubles. Such problems include a situation where the car jerks during acceleration, or there are interruptions when driving at low speeds.

The best way to get rid of surprises is prevention and correct diagnosis. With their help, you can do without expensive repairs.

It is difficult to carry out diagnostics with an unevenly running car that is idling. The correct solution would be to identify interruptions during its movement. For this, a straight-line section of the road without heavy traffic is selected.

While driving, we turn on the gears one by one. At each included stage, we sharply depress the accelerator pedal. The power plant must be sensitive to all the efforts of the driver. In those cases, when the car jerks when you press the gas pedal or does it without any effort, then the vehicle needs a more careful inspection of individual components. It all depends on the specific behavior of the car.

Intermittent movement during acceleration

Problems of uneven movement during a high-speed maneuver most often lie in the unstable flow of fuel into the float chamber. Gasoline is produced faster than it enters it. The supply of liquid to the gasoline pump is carried out intermittently.

You need to solve the problem by opening the fuel pump cover. We carry out a visual inspection of the hole with the valve. The seal is often out of place. This lack of sealing leads to a complication in the supply of gasoline to the system, because of this, the car twitches while driving. The necessary operation is to replace the valve and resume tight operation. If there is a seal on hand, then you can do it yourself.

Unstable movement at low speed

Troubles occurring while driving at low speed are the result of incorrect operation of the injectors. The culprit is also often a loose bundle of wires that can fray if rubbed against the fuel pipes while driving.

Bare wires are shorted to tubes. In this case, the injectors are disabled, and the stability of the injection suffers. If wires are the culprit behind the fact that the car jerks when driving at low speeds, then it is better to change the message of the harness. After replacement, it is necessary to fix them on the body to avoid the recurrence of the problem.

Instability associated with pressing the accelerator

At a time when the driver "presses the gas", the car pulls back, this may be due to the ineffective operation of the vacuum ignition angle regulator. This element is located in the distributor.

Since gasoline burns at the same speed, the driver seeks to increase the engine speed and presses the pedal, the engine needs to ignite the air-fuel mixture faster. The work of the vacuum regulator begins just with an increase in revolutions above 1500-2000 rpm. The opening throttle valve simultaneously pulls off the bearing due to the resulting vacuum, which increases the ignition timing.

To diagnose the operation of the vacuum regulator, it is enough to remove the hose and tightly cover it with your hand. You will hear how the suction effect works. When the air enters inside, the vacuum is not formed, the tightness is broken, and when starting off the car jerks.

Another culprit behind why the car jerks on the move is the accelerator pump spray. You can see the performance of the element after removing the diffusers. Then you have to press the lever and watch their work. Failure means that one of the unstable problems has been detected.

To repair the mechanism, you will need to dismantle it and remove the ball, gripping the lower side with pliers carefully so as not to deform the case. With the help of a compressor, we purge the channels and, having assembled it, we install it without gaps. The resulting gaps will lead to unwanted discharge. Correct operation and purge cleanliness is assessed by a long, straight jet.

Rare aperture case

A malfunction with the accelerator pump diaphragm is not detected so often. Only the spring remains in the structure, and its cover disappears. You have to make a homemade button from available tools. If such a problem is identified at the station, auto mechanics suggest completely changing the carburetor so as not to mess around with trifles.

The culprit-filters

When the car jerks when driving at low or high speeds, then it is necessary to remember how long ago the fuel filters changed. In diesel power plants, as a rule, they use a pair: coarse and fine cleaning. The main trouble is the second.

Fuel filters

To check the condition of the coarse filter, you can fold back the fuel hose and blow through the mesh. In this case, the cap on the neck of the gas tank should be unscrewed. After a couple of days, we repeat the procedure. If the result is negative, you must take care of the cleanliness of the fine filter. Almost all foreign cars use disposable fine fuel filters. The procedure for adding a small amount of fuel to the filter will help to add efficiency after replacing it.

A clogged fine filter leads to unstable engine operation, but this car does not twitch. The motor often stalls or suffocates.

Spark test

Some cars start to work with jerking on descents or on some level areas if there is a problem with the contactless ignition system. A faulty switch located inside the structure can cause such consequences. Repair with this element is not carried out. You will have to completely replace the assembly.

Control unit monitoring

In some situations, car owners are advised to check the carburetor control unit. A characteristic feature of the occurrence of tremors is their random occurrence or poor predictability. You can send the car to a diagnostic stand at the nearest car service. There you can detect instability at idle, the appearance of jolts when you press the accelerator pedal and the formation of "floating" revolutions.

Carburetor control unit

Often, for carburetor cars, the cause is identified in the carburetor control unit. It is practically impossible to independently diagnose this node "by ear" or by the consequences of the operation of the motor.

Conclusion

The emerging instability or intermittent operation of the car can in many cases be diagnosed and "cured" by yourself. This will cost significantly less than at the station. If you don't have enough experience, you can contact your friends or check several "suspicious" sites. It is not worth delaying the solution of the problem, since such an unstable operation of the car negatively affects the rest of the components and overall safety while driving.

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

These jerks are rapid changes in the crankshaft speed, regardless of the position of the gas pedal and the degree of pressing the accelerator. Typically, these jerks follow in series, causing the engine to jerk.

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 the revs. Moreover, in both cases, during a smooth pressing of the gas pedal, the set of revolutions 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 opportunity to overtake, quickly change lanes, etc. To solve the problem, the engine needs in-depth diagnostics, since first it is necessary to clearly determine the cause of the breakdown.

Read in this article

Why the engine jerks during acceleration: the main reasons

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

Air leaks and sensors

As you know, the injection engine is equipped, 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 supplied fuel, prepares a fuel-air mixture that will be optimal for a particular mode of engine operation, etc.

So, the engine can twitch if there are problems with. Normally, when the accelerator pedal is pressed sharply, the sensor sends a signal to the ECU that the damper is wide open and the fuel supply needs to be increased.

If the signal is incorrect, then the fuel supply may be implemented incorrectly. In this case, a failure appears, which the driver senses 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 periodically cleaned, and on many cars it is required to carry out the procedure after cleaning this element. To avoid problems, experienced drivers clean the throttle valve at least once a year. This procedure is performed as a preventive measure.

Also on the list of sensors that can cause the engine to jerk during acceleration are the camshaft position sensor DPRV and the 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, electronic sensors are checked by the exclusion method; a tester-multimeter is used for diagnostics.

As for air leakage, this 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, a 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 are also possible problems in the fuel supply system. In any case, depressurization requires immediate detection of the problem area.

What is the bottom line

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

Also, a common case is such a situation when the engine roars during acceleration, while the car does not accelerate, jerks, 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, this is how the automatic transmission malfunctions manifest themselves, but one should not exclude the problematic clutch on the usual "mechanics".

In such a situation, an urgent diagnosis of the transmission is required. It is easier to deal with a manual transmission by replacing the clutch disc, basket or the entire assembly. On cars with a classic torque converter automatic transmission or manual transmission (robotic gearbox), when jerks appear, it is necessary to stop operating the vehicle.

Then you need to check the oil level in the automatic box and its condition. Next, you 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.

Reasons for overclocking failure

Gas wiring;
Poor mass.

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

Even if the engine is working properly, the car may move jerky when accelerating. Motors that meet environmental standards Euro-4 and higher have such an unpleasant property. The point is the reaction of the electronic throttle valve to pressing the gas pedal. It is non-linear for the first 3-4 centimeters of travel. This can lead to overclocking failure.

Shifting gears softer;

Car owners often notice that the car jerks when accelerating. Such dips mainly appear at low and medium speeds. They are characterized by the following:

Failure from 2 to 9 seconds;
A jerk in 1-2 seconds;
Twitching - a series of jerks;
Swinging is a series of dips.

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

Reasons for overclocking failure

You can use diagnostics to determine the reason why the car jerks. Possible problems:

On HBO, the problem may arise due to:

Bad LPG control unit;
Interference in the harness to which the fuel injectors are connected;
Gas wiring;
Poor mass.

How to fix overclocking dips

Check wires and ignition coils. In case of breakdown, the spark plug wires spark and glow in the dark. The engine troit, twitching appears. This comes from "age", poor quality parts or poor contact with candles. The problem may be related to engine temperature. The interwinding resistance of the coils and the thermal mode of operation change together, which is why the car on gasoline jerks during acceleration.
If you have a diesel engine, jerks during acceleration are definitely not related to the operation of the coils, they are not there.
Inspect the spark plugs. Poor contact with wires, heavy carbon deposits, too lean or rich fuel mixture will destroy them. Unscrew and check each spark plug as in our article "Diagnostics of the internal combustion engine by spark plugs", where we gave examples of faulty spark plugs.
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.

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Improves overall dynamics, idle and low-speed traction;
The car does not dull when the air conditioner is on;
Shifting gears softer;
Reduces fuel consumption while maintaining driving style.

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Symptoms of problems with acceleration sooner or later occur in cars with high mileage. The driver may not even notice the first signs of a malfunction while driving without extreme loads. Test modes for such defects are driving uphill or abruptly pressing the gas pedal. In such situations, the breakdown manifests itself in the fact that the car twitches during acceleration and does not gain momentum.

Engine processes

When you press the gas pedal, the fuel pump builds up pressure in the line and pushes the gasoline through the fuel filter to the injection system. There, a fuel-air mixture is prepared, which is fed into the cylinder in the form of fine dust. At this moment, the spark plug ignites the mixture, which, by burning, sets in motion the pistons, which turn the engine crankshaft with the help of the crank mechanism.

The combustion products are discharged from the cylinder and the process is repeated. Removal is accomplished by opening the exhaust valve, which allows the piston to push the exhaust gases out through the exhaust manifold. The exhaust is cleaned using a catalytic converter, then their energy is extinguished by a silencer, after which they are removed through the exhaust pipe. In general, the situation is similar with engines for motorcycles, only they have a smaller engine displacement. Therefore, if you are tired of the car, then it makes sense to switch to a motorcycle, only in advance you need to find yourself an inexpensive helmet for a motorcycle, since there is no point in buying an expensive one, for a start it is better to start with something simple. This also applies to the motorcycle itself.

Another element can be included in this cycle: some of the unburned fuel with solid particles of hydrocarbons is recycled and again burned under the control of sensors for the content of pollutants in the exhaust.

The engine performs all these processes at a speed of 1200 rpm at idle speed. When the throttle is opened, the combustion is more intense, the rpm rises and, if the transmission is connected, the car starts to accelerate. An engine needs three things to cycle properly: reliable ignition, sufficient air and fuel. If there are abnormalities in the operation of the engine, leading to the fact that when the gas is pressed, the car jerks, then, most likely, one of the following processes does not work as expected:

fuel supply;
preparation of the mixture;
ignition.

Jerks during acceleration can be signs of irregularities on any part of the entire fuel supply route from the tank to the engine. The internal combustion engine is sensitive to depressurization of the fuel line and the problems of fuel leakage from it. Damage to the fuel line can lead not only to the fact that when the gas is pressed sharply, the car does not react immediately, but even to a fire or explosion. Therefore, a sensible first step in diagnosing fuel starvation is to inspect the area under the vehicle for fuel leaks.

The smell of gasoline in the cabin or trunk should also cause suspicion.

Filter and tank check

The fuel filter is responsible for cleaning the gasoline before it enters the injection system. It can be clogged with debris, dirt and other particles from the tank or fuel suspensions. Usually the filter is attached inside the engine compartment on the main line before the mixture formation system. If there is no certainty regarding the date of its last replacement, then clogging of the filter as a possible cause of jerks during acceleration should be considered more carefully. To understand whether it is he who is the problem, you must:

Physically inspect the fuel filter. If it is visually obvious that it is dirty, then it is likely that the blockage is causing the restriction of the fuel flow to the engine.
Check the tightness of the connections at the splices of the fuel lines with the filter housing. There are frequent cases of loosening of connections before the system is depressurized.

If these problems are found, replace the fuel filter and tighten the threads on the connections.

Then check that the leak has stopped and test the engine again. In some cases, the tank ventilation system may be clogged. The problem is not noticeable with a full tank, but with its emptying it can manifest itself as dips during acceleration.

Troubleshooting pump problems

The fuel pump in a modern car is most often a submersible type and operates on an electric drive. Its task is to pump fuel out of the tank and push it along the fuel lines in the desired direction. Opening the throttle valve increases fuel consumption. Accordingly, the pump in this case increases the pressure to meet the engine's demand for gasoline.

Problems in pump operation can lead to jerks when picking up speed. Typically, these symptoms indicate the first signs of wear and tear.

Analyzing and troubleshooting fuel pump problems requires professional diagnostic equipment to scan and interpret error codes. Or you have to remove the pump and check its operation. If you suspect a malfunction, a complete replacement is recommended.

Lack of air

The air filter is designed to clean the air from road debris, dust and other components that can damage the engine. This element is capable of accumulating dirt until it is completely obstructed. A clogged filter is the most underestimated reason a vehicle will run unevenly due to inefficient fuel combustion.

Another popular cause of spasmodic vehicle acceleration is the MAF sensor. The component performs the task of measuring the amount of intake air and transferring data to the on-board computer. A defective or dirty sensor manifests itself as a loss of engine power and an increase in fuel consumption.

Oxygen sensors

Most modern car engines are equipped with oxygen sensors (lambda probes). Their number can be up to several pieces, depending on the car model. The presence of such a control loop contributes to the smooth and economical operation of the engine. Typically, you can find two types of such sensors:

Upstream lambda probes. Located inside the exhaust manifold and designed to measure the oxygen level in the vehicle exhaust during the exhaust stroke. Their task is to control incomplete combustion.
Downstream sensors. Located behind the catalytic converter. They transmit to the computer the information necessary to fine-tune the ratio of fuel and air in the mixture.

If one of these sensors fails, incorrect information is sent to the processor that controls the engine, which can lead to problems with acceleration of the car. In order to diagnose the health of lambda probes, professional equipment is required to read and analyze error codes from the on-board computer.

A typical internal combustion engine burns about 80% of the fuel in the cylinder. The reason for incomplete combustion is that the fuel contains complex hydrocarbon molecules that are not easily oxidized. Larger molecules are unable to burn without increasing the reaction time.

The exhaust gas recirculation system was invented and implemented in the late 1960s. Its essence lies in directing heavy hydrocarbon molecules from the exhaust gases back into the combustion chamber through the intake manifold. The elements of this system (primarily the EGR valve) become clogged with carbon deposits over time, which reduces the efficiency of the engine. In order to diagnose or fix a problem with the recirculation valve, you must:

Remove the EGR valve.
Check EGR chambers for excess soot. Inside, the valve is a series of chambers through which the solid fuel particles enter the manifold. If they are clogged, then the engine may show itself jerky in operation.
Check the auxiliary components of the recirculation system for damage. In its work, sensors and vacuum components can be involved, which increase the efficiency of the EGR operation. Any of them can be damaged and lead to traction failures.

Ignition and injection

During normal operation, the candle receives an electrical signal from the distributor or electronic injection system and sends a current pulse to the electrodes in a split second. This ignites the vapors in the combustion chamber. However, there are many reasons why a candle may stop sparking properly.

Problems like this can cause the engine to run unevenly when accelerating.

There are many methods for detecting and fixing spark plug problems, but diagnosis is best done by a specialist. A novice mechanic can do the following:

Check the wires going to the candles. Sometimes engine unevenness is caused by damage, wear, or improper spark plug wiring.
Replace the suspicious candle. Throughout the entire service life, it must retain its original appearance. If the plug is damaged, covered with oil or carbon deposits, you should contact a professional for further diagnostics of the causes of this condition.

Another factor in why the spark plug is not generating a spark may be a malfunctioning ignition coil. This important component raises the voltage of the car network to 30,000 volts, which is the main condition for sparking. Coil defects cause misfiring, which manifests itself as jerks in the vehicle.

Another common problem in the ignition system- contamination of the injector nozzles. This is not a very serious defect, but it also needs to be fixed. It is advisable to clean the nozzles on a regular basis to avoid costly replacement.

This procedure can be carried out independently using a special cleaning kit, which is inexpensive and always on sale.

Other reasons

The reasons for the jerking of a car when accelerating are not always found in the engine. Sometimes this is due to the operation of the clutch on vehicles with a manual transmission. For example, the clutch disc may be worn or deformed. A faulty release bearing manifests itself in a similar way. Some craftsmen do clutch repairs on their own, but for most drivers, such work will require additional knowledge.

Uneven engine operation in some modes also manifests itself as malfunctions of on-board electronics. Sometimes the engine control unit or other electronic component malfunctions. In most cases, a simple reboot of the software is sufficient to restore the functionality of the engine management systems.

Not a very common diagnosis of acceleration dips, but sometimes this is the case. Generator task- create the required voltage while the engine is running. Like any other mechanism, it is subject to wear and tear, which leads to a loss of its productivity. Voltage drops affect the operation of the fuel pump and ignition system.

Adverse weather conditions can also cause jerking when accelerating. Humidity and temperature drops in the cold season provoke the formation of condensation on the contact groups and in the electronic housing. Cars of old designs equipped with a mechanical distributor are especially sensitive to the weather.

Misting of its lid leads to sparking in the distributor itself, and not on the candle. Ignition misfires manifest themselves in jerks while driving.

The obvious way to prevent this is to leave the vehicle in a drier, warmer environment. If such storage is not possible, then the only way to get rid of the condensate is to drain the inside of the distributor cover.

With signs of uneven acceleration, the worst breakdown for diesel engines is turbine failure, since both the part itself and its replacement are not cheap. Typically, compressor failure symptoms are not sudden. And the later they are identified and eliminated, the more expensive the repair will be. Therefore, it is important to remember that defects in the turbocharger must be repaired in a timely manner. The main signs of impending failure:

turbine whistle;
blue or black smoke from the chimney;
loss of power during steady movement or acceleration.

Also, turbine pressure sensor failures are not uncommon, due to which the air compression may not meet the needs of the engine. It is an inexpensive part that can be replaced with a hobbyist tool.

Leaks in vacuum hoses are more common causes of jerky movement. These black inconspicuous pipes have a great influence on the operation of the diesel engine. If damage or rupture can be detected, self-sealing is not difficult.

It can be said that most of the causes of jerking in both diesel and gasoline vehicles can be eliminated and even prevented by regular maintenance. This is often simply the result of dirt or wear on parts. Other causes are less common and it is better to eliminate them in specialized workshops.