VAZ 2109 carburetor twitches while driving

>If the VAZ 2109 jerks when moving, then the reason lies in one of the following malfunctions: 1) Problems in the VAZ 2109 power system.

Power system VAZ 2109

2) Problems in the ignition system of the VAZ 2109.

Ignition system VAZ 2109

Dirty fuel filter VAZ 2109

2) Mesh filter in . A clogged filter leads to the same thing - the VAZ 2109 carburetor does not receive the required amount of fuel. It is necessary to check the cleanliness of the filter and, if necessary, blow it with compressed air. 3) VAZ 2109 carburetor accelerator pump. If the car jerks during acceleration, this very often indicates a malfunction of the VAZ 2109 accelerator pump. 4) Sediment in the carburetor float chamber. If the VAZ 2109 jerks not during acceleration, but precisely when the car is moving evenly with the gas pedal in a fixed position, then this may be caused by debris getting from the float chamber into the fuel nozzles. To check, remove the carburetor cover and make sure that the float chamber does not contain sediment. 5) Fuel pump VAZ 2109. If the car jerks at high speeds, then perhaps the fuel pump does not provide the necessary fuel supply. To increase the fuel supply, adjust the fuel pump pusher.

Adjusting the fuel supply in the fuel pump VAZ 2109

6) Poor quality of gasoline. It happens that you can refuel with gasoline mixed with water. Naturally, water does not burn, and when it gets into the engine it causes the engine to jerk. 7) Low fuel level in the tank. Due to the fact that fuel is mixed with air, the car may jerk. Here, in principle, are all the main reasons for the fuel system. In principle, everything is clear: first, we check the carburetor to ensure it is not clogged and the fuel supply. If everything is in order, then the ignition system of the VAZ 2109 comes under suspicion. Malfunctions of the ignition system of the VAZ 2109, causing the car to jerk. 1) Vacuum corrector of the ignition distributor of the VAZ 2109. We check the tightness of the tube from the carburetor to the vacuum corrector, as well as the ease of movement of the correcting shutters.

Ignition distributor VAZ 2109

2) Burning of the ignition distributor contacts. 3) Test for ground or spark plugs. If the engine operates properly at idle, this does not mean that it will behave this way in all engine operating modes. Under load, due to poor insulation, a spark plug or high-voltage wire can be pierced to ground, but work normally at idle.

High-voltage wires VAZ 2109

4). The switch may also behave inappropriately. It may work fine, and then, within a couple of minutes, misfire. Personally, I always carry a spare switch with me. I know that many people do the same. Therefore, if possible, install a spare switch and ride it. If the problem goes away, then the problem was in the old switch.

Switch VAZ 2109

5) When the ignition coil overheats, it can also be the cause of jerking in the VAZ 2109. As you can see, there are many reasons, and it is not always immediately clear where to go. But if you check all the points listed above one by one, then the reason that the VAZ 2109 is twitching will be discovered.

Why does the VAZ 21099 carburetor twitch during acceleration?

If you encounter a problem such as the VAZ 2109 jerking while driving, then the reason may be hidden in a malfunction such as:

Power system problem.
Ignition system problem.

Also, one of the main reasons that the VAZ 2109 jerks when driving is the carburetor, which urgently needs to be checked.

To determine if a car is broken, you must first prepare two wrenches (one eight, the other ten), two screwdrivers (one Phillips, the other straight), as well as a clean rag and thin copper wire. You will also need a compressor and liquid.

Let's sum it up

So, we see that a car can jerk for many reasons. As a rule, it helps to alternately replace consumables (filters, spark plugs, armored wires) and clean the injector nozzles. It is better to entrust the check of electronics and sensors to a specialist at a service station.

Often the problem can also lie in the transmission; the car also “jumps” in this case - especially with an automatic transmission, although manual transmissions are also prone to failure. In a manual transmission, replace the basket and/or clutch disc.

The automatic transmission checks the oil for its level and quality. Please note that qualified repair of an automatic transmission “in a garage” is impossible; it must be diagnosed at a service station.

Source

Your actions

Remove the cover from the air filter.
Remove the filter.
Remove the drive vacuum corrector hose.
Replacing the corrector (possible).
Check the carburetor.
Remove the hose that leads to the fuel.
Pull the distributor out of the socket.
Clean the nozzle hole.
Put the sprayer back.
Assemble the carburetor.
Check the retraction of the drive lever.
Check the trickles.

Next, most likely you will have to go to a service center or read how to properly adjust the carburetor here.

If the VAZ 2109 carburetor twitches during acceleration

It also happens that the carburetor of a VAZ 2109 twitches during acceleration. In this case, the list of reasons is quite large and it is not so easy to determine what kind of malfunction led to this behavior of your car.

incorrect operation of the gasoline pump;
problems in the fuel filter;
clogging of the additional filter;
there are ignition problems;
very low fuel level in the tank.

And this is not a complete list. It will be quite difficult to find the reason on your own. If the carburetor twitches when accelerating a VAZ 2109, then it is better not to try to repair the car yourself. In this case, contact the service center and professionals who will be able to find and eliminate the cause of the problem. And it’s better not to delay contacting the salon for too long.

It also happens that the carburetor of a VAZ 2109 twitches during acceleration.

In this case, the list of reasons is quite large and it is not so easy to determine what kind of malfunction led to this behavior of your car.

On diesel

Some of the reasons for power loss listed above are also relevant for diesel engines. But there are also a number of specific points associated with diesel engines that should be mentioned. One of the most common causes of power loss in a diesel engine is the failure of the turbocharger. When this unit fails, it usually begins to emit a characteristic whistle, which is difficult to confuse with something else. But in order to accurately determine the breakdown, you will have to send the car to a car service center. There they will scan it and identify the problem. Why might the turbo turn off? Here are some options.

The charge air pressure sensor has failed.
The turbine has simply exhausted its factory life.
The tightness of the joint between the compressor and the motor is broken.
The air path is clogged.
The turbocharger axis has become coked, causing its rotation to slow down.
The turbocharger shut-off valve has failed.

A characteristic external sign of a compressor failure is blue smoke coming out of the exhaust pipe.

It occurs due to the combustion of oil, the excess of which enters the combustion chambers of the cylinders due to leaks in the compressor. If the tightness of the compressor discharge line is broken, air leaks occur and the mixture becomes too rich. When it burns, not blue smoke comes out of the chimney, but black smoke. Finally, white smoke indicates that the oil line through which oil is drained from the compressor is clogged.

Causes of malfunction

Troubleshooting is an incorrect air-fuel mixture ratio in the combustion chamber or a lack of spark. In this case, the crankshaft may turn with difficulty, or there will be misfires.

Many car enthusiasts started with carburetor engines and therefore know perfectly well why the engine misfires, but not everyone can fix the problem because they don’t know what the problem is. It is worth understanding that the tripping effect occurs due to a disruption in the supply of one of the elements - air, fuel and spark. It is in the systems that are responsible for these elements that we should look for the cause.

So, let's look at the components where you should look for the reason why the VAZ 2109 engine with a carburetor injection system is tripping:

Carburetor.
Fuel.
Fuel pump and filter.
Spark.
Air filter.

Jerking when adding gas

You should start by checking the ignition system. Symptoms of its malfunction are a decrease in power with an increase in gasoline consumption. The culprits are candles, armored wire or coil.

After turning off the ignition, you need to check the reliability of fastening the armor wires to the spark plugs and the coil itself. If nothing is found, turn on the ignition, check if there are any sparks or a characteristic crackling sound - this means a spark breakdown.

If a fault is not found, we inspect the spark plugs, the electrodes should be free of carbon deposits, the insulator should be intact, this is especially true if the car “shoots out”. You can try putting in spare spark plugs if you have them.

The next search is to check the camshaft sensor.

The next step should be to check the power system. The tank must be filled with suitable, high-quality fuel. Fuel filters should not be clogged, otherwise the engine in the car simply does not have enough fuel. To properly prepare the mixture, sufficient air is also necessary; the air filter must also be checked.

If the filters are clean and the problem persists, we check the injector (diagnostics of the injectors, also for contamination). The last step should be diagnosing the engine firmware, but this is already done at the service station.

Take care of those you have tamed

But never set foot on a compromised gas station! Use only proven network gas stations. You have an “old” car, it needs to be cared for and cherished, given regular oil from certified manufacturers on time, filled with high-quality gasoline and loved.

It is not hard. There are quite a lot of reputable companies in the country that have long and tightly occupied their market niches, care about their reputation, and have certified quality assurance systems. Among them are representatives of the world's largest oil companies. They carry out geological exploration, development, and exploitation of oil fields, production and marketing of petroleum products. The gas stations of these companies offer all types of motor fuel.

A typical gas station is usually a large complex with 12 or more gas stations. The driver can get the necessary assistance from a gas station attendant, pump up the tires of his car, top up the radiator with water, use the toilet at no extra charge, and shop at a self-service mini-market where snacks and drinks, including chilled ones, are available. Gas stations have a small cafe; the gas station often smells of freshly brewed coffee.

Don’t be fooled by the cheapness, fill in with high-quality fuel and go ahead.

A situation where a car starts to jerk for no reason can occur to every car owner several times a year. In most cases, the problem can be resolved quickly. At the same time, you need to understand that the maximum wear of some machine components can lead to a major overhaul of the affected systems. If the car stalls while driving and jerks with a loss of speed, then it’s time to take action.

Malfunction of the gas distribution mechanism

Breakdowns or incorrect adjustment of the gas distribution mechanism shifts the gas distribution phases from the optimal point and causes a sharp decrease in engine power. This occurs due to incomplete release of exhaust gases from the cylinders, or insufficient filling with air or the air-fuel mixture. If the timing chain or belt jumps one or more teeth, it disrupts the operation and adjustment of the mechanism that provides the required ignition timing depending on engine speed. A significant drop in power is also observed when the timing valves are incorrectly adjusted, when they are insufficiently opened or not completely closed.

How can I find out the circumstances of the malfunction?

You will need two wrenches - “ten” and “eight”, a Phillips screwdriver and a straight, clean rag, a little bronze wire. The wire diameter should be already 0.3 mm.
In addition, liquid and a WD40 compressor will be useful.

The operating procedure is as follows:

Armed with a ten key, remove the cover from the air filter housing by unfastening the spring fasteners. Remove the filter. Using an eight-mm wrench, unscrew the nuts and now you can loosen the clamp on the crankcase ventilation hose where it connects to the valve cover. It is then possible to remove the filter housing.
Now you need to remove the vacuum corrector drive hose and create a vacuum to make sure it is tight.
Perhaps the corrector will need to be replaced. It’s better to entrust this to the car service workers.
If the air space is not able to flow freely during purging, then look at how things are going with the carburetor. For example, make sure its air damper is open. When you press the throttle
, a stream of gasoline should come out of the nozzle. Make sure that they are present and the direction of fuel spray is correct.
If any trouble occurs, the car must be sent for service.
Carefully remove the hose leading the fuel to the carburetor, without spilling gasoline. We do the same with the choke control cable, and after that with the wire that is located

idle
air solenoid valve . Now unscrew the screws securing the top carburetor cover. After removing the lid, place it with the floats facing up so as not to damage it.
Now, using a screwdriver, carefully pry up the nozzle tubes and remove it from the socket.
Once you have done this, you need to take the narrow bronze wire and carefully clean the holes in the spray nozzle. Later, go to blow it in the opposite direction (against the movement of fuel).
We install the sprayer. At the same time, without closing the carburetor cover, it is necessary to press the damper drive lever. We control the appearance of streams of fuel running from the sprayer tubes.
We assemble the carburetor.
If there were no streams, then you need to check how easily the accelerator pump drive lever moves. In addition, we check whether there is any play in the drive. If necessary, we lubricate it with WD40 and replace everything that is faulty.
Again we control the trickles. If they are present, we assemble the carburetor. If not, we go to the service center.

FakeHeader

Comments 39

There was a problem of the same kind.
It turned out there was a bad contact on the plug that goes to the hall sensor, or rather the minus was bad. In short, I discovered the cause and eliminated it. There was a bad contact on the connector of the HOL switch (which is on the distributor). During sharp acceleration, the engine leaned back and the contact lost power. Thanks to all.

I was happy early. Traveled 10 km. and twitched. I repeated the procedure with suction (up to 5 tons of volume) and drove off again. 15 km. the flight is normal. These are the miracles.

I'll report back briefly. I remembered that the carb has a fine filter, so I decided to take a look. He unscrewed it, pulled out the mesh and blew it out. Although she was already clean. I decided to tug on the explosive wires and accidentally touched the wire of the coolant temperature sensor. The engine jerked. The wire began to move, the engine began to twitch. Disconnected the motor wire. stalled. Pressed the contacts on the terminal and inserted it into place. I started the engine, warmed it up and pulled the choke sharply several times. Raising the speed to 3x.-4x. thousand...And she GO! I don’t know what happened. I drove around the area for about 10 minutes, it goes as before. Some kind of miracles. Thank you all for your kind words and participation!

accelerator pump / hall sensor / switch / capacitor in the distributor / perhaps one spark plug is cut out. It's easy to check the fuel pump; you rip out the hose from the carb and start the car.

you think correctly, the accelerator is most likely clogged

I was also twitching, I changed the fuel pump with the rod and cleaned the carb with all the jets. The problem is gone.

Now I have carried out “diagnostics”, the pump pumps normally, the accelerator splashes where it should, it accelerates well in place and does not stall. But he doesn’t want to go. And only FORWARD, engaged the rear, starts with slipping, and jerks forward. That's funny! Now I’ll go with the choke and try to get going.

remove the carb and blow it out and check the membrane at the same time

Yes, judging by the quality of the gasoline + all sorts of other crap accumulates in the tank over time, something clearly gets into the carb and it’s clogged. remove, rinse, blow, change membranes if bad

if it jerks during acceleration, you need to start with the fuel system, change the filter, flush the carburetor, the problem I think is that at the time of acceleration there is not enough fuel in the chamber, this is purely my opinion)

If your engine runs smoothly with smooth throttle release, then what does the ignition have to do with it? obvious lack of fuel. look from the pump to the carb. Most likely just clean the carb and everything will be fine.

Mmm. and the carb did not unwind? I had something like this right after the purchase, it was unexpected

Look at the fuel pump rod!

The advice is to remove it, wash it and rehearse the carb and forget about it.

I think it’s something to do with the carb; on my 9th, in three years, I had these symptoms twice! and all the carbs! and during jerks the suction did not try to tighten! I passed!

On the O6 the accelerator was soaring and the brain was simply infuriating during aggressive driving.

In any case, the vacuum seal disappears, half of the people drive without it, most likely it really is the accelerator

which half? You and your loved ones?

This happened to me because of the ignition coil! At first I thought the carb was removed, cleaned, installed, but it still twitches... replaced the coil and everything is OK))

Yes, it seems like she should have three then. Moreover, at any speed, with a load (while driving) and without.

it can’t triple because of the coil... if it can light 3 candles, then why can’t it light the 4th? Hence the conclusion that the problem is either due to the distributor cap, or the drive, or the spark plug

Well, we don’t take fuel and compression into account now... So install a known-good coil... The person says that this happened). maybe triple! it just may not work at a certain moment... the cylinders will trip one by one, I couldn’t figure out which cylinder was tripping!

maybe triple! it just may not work at a certain moment... the cylinders will trip one by one, I couldn’t figure out which cylinder was tripping!

Yes, it seems like she should have three then. Moreover, at any speed, with a load (while driving) and without.

I just had severe misfires... and the coil either worked normally, or there were misfires. sometimes you drive 90 km, everything is fine, and suddenly it starts to twitch... you give the gas to the floor, a huge dip appears, and the revolutions drop, and if you press the gas little by little, it twitches very weakly

The benefits of taking radical action

To the desperate question of what to do in this deadlock situation, when no matter what you do, the VAZ 2109 injector still twitches when driving, two answers are possible: palliative and radical. A palliative response is a half-measure that temporarily provides a way out of a difficult situation. It does not eliminate the essential cause of the problem, does not fight the roots of the problem.

Such a palliative could be contacting a service station. The master will kick the ramp, move the high-voltage wires, raise his eyes to the sky... Maybe he will conduct computer diagnostics. At best, it will replace the spark plugs and fuel filter. If the outcome is favorable, you will even drive your VAZ 2109 carburetor or injector for several thousand more kilometers. Under certain life circumstances, such a palliative option makes sense.

But seriously consider taking radical action. Be smart: sell your “nine”! Unreasonable malfunctions are the strongest argument to part with your car immediately. A car should carry its owner, and not give him food for thought while driving. A modern person has a lot to think about even without a “nine”. Don’t waste your life struggling with problems with acceleration in a twenty-year-old domestic car - you risk wasting your life entirely, without a trace.

The only time it makes sense to fight for the performance of your nine is when you know why it actually twitches while driving.

In the vast majority of externally determined cases, this is low-quality fuel. If for some reason you happen to fill up the tank at an untested gas station and after a short time the car starts to jerk, it’s a problem with the fuel. You have a choice. The twitching can be tolerated as long as it is not too severe. In this case, you should use up as much fuel as possible, then fill the tank at a reputable gas station and continue driving without problems. If you don’t have the strength to endure the jerking, stock up on a long thin hose, drive the car onto an overpass, suck it up, drain the fake through the hose, fill it with high-quality fuel and drive calmly.

Cleaning the injector

On the other hand, if the car starts normally, but the jerking is detected only while driving, most likely, standard injector cleaning will help completely solve the problem.

Before moving on to cleaning the injector (which, in fact, cannot be called a simple procedure), it is recommended to check the functionality of the spark plugs. It may well be that it is because of them that the injector twitches.

If everything is in order with the candles, you need to move on to further actions.

Clogging of the mechanism varies. Experts distinguish three stages:

The last stage is extremely dangerous, since the engine will soon come to an end if measures are not taken.

Flushing

Car enthusiasts who do not have specialized knowledge of an auto mechanic should not even think about flushing the engine with their own hands. It is recommended to order the procedure at a service station, where experienced professionals will carry out all the necessary measures.

The danger of washing yourself is that, unknowingly, you can make things even worse. The engine is a delicate thing, and it is possible that after washing it will not start or work at all.

However, some owners, having seen how the masters do it 1-2 times, having familiarized themselves with theory and practice, next time they cope with this matter on their own.

Liquid flushing

This is the first type of flushing of an injection engine. The machine starts, but is disconnected from the power system. Then flushing equipment is connected to the motor, supplying liquid directly to the injectors. This procedure is carried out on a hot motor, i.e., it functions as it moves.

It is extremely important that liquid does not get into the fuel tank, otherwise it will lead to dire consequences. Its composition is caustic and easily decomposes deposits on the walls, which will ultimately lead to severe clogging of the filter and pump. You will definitely have to change them.

As for the type of flushing fluid, it depends on the following: the age of the machine and the degree of contamination. You need to entrust the choice of flushing fluid to specialists who deal with cleaning injection systems periodically and have already gotten their hands on it. They will be able to choose exactly the composition that will not harm the engine.

Regarding the timing of liquid washing, this is clearly stated in the regulations. Carry out one flush every 30,000 km.

Take care of those you have tamed

Don’t be fooled by the cheapness, fill in with high-quality fuel and go ahead.

The situation when a relatively new car, obviously without any defects, stumbles along the way, is known to experienced drivers of vehicles equipped with an injection system. Why does the car jerk when the injector moves, what are the reasons for this? This will be discussed in the article.

Replacement procedure

Some may wonder how many engine mounts there are on a VAZ-2109. In fact, there is only one, but the total number of engine and gearbox mounts is three. To replace the rear cushion, perform the following steps:

Place the car on a viewing hole or overpass.
Secure the car using special wheel chocks, and be sure to set the handbrake.
It is advisable to disconnect the negative terminal from the battery.
Using a spanner, you need to unscrew the nut that secures the airbag to the body.
Unscrew the nuts securing the support bracket to the gearbox housing. There are only three nuts located there.
Remove the old cushion, first remove all the bolts.
Install the new cushion and tighten all threaded connections.

Replacing the left side airbag is done in approximately the same way, but you will have to remove the left mudguard on the engine. If there is protection, it must also be removed.

Troubleshooting Methods

It is important to know that engine tripping can occur both when the car is moving and at idle speed. During this, popping sounds will occur. But the car jerking will only occur while it is moving.

The carburetor in a car is a rather finicky thing. Therefore, many are already aware that tripling can occur precisely because of the carburetor. In order to fix a car problem in the form of engine tripping, it is necessary to clean and overhaul the carburetor. You can clean the carburetor yourself by hand or using a special oven. But almost all car owners, as a rule, do this manually. The next step is to adjust the carburetor. In order to adjust the carburetor, you need to take the screws and adjust until the fuel and air-fuel mixture reach the optimal ratio. To sum up, we can say that it is possible to fix such a problem as the VAZ 2109 carburetor jerking when driving, but first find out the cause of this breakdown.

About the transmission

Now a few words about the transmission, since it can also cause jerks when driving.

As you know, cars use manual and automatic transmissions.

As for a manual transmission, the gearbox and everything that follows it cannot cause jerking.

A manual transmission is a fairly simple design, and if it already breaks, it breaks specifically, and not creating jerks.

But the clutch can cause jerking. If it is heavily worn, in particular the driven disk, or “slips,” then the car easily begins to twitch.

But as a rule, jerking and twitching with such malfunctions occurs during gear shifting.

But in automatic transmissions, the cause of the twitching is precisely the gearbox itself.

It is very dependent on the quantity and quality of oil, so a lack of oil or its foaming can easily cause uneven running of the car.

You can measure the oil level in the automatic transmission using a dipstick.

Or without.

It all depends on the design of the automatic transmission.

How to measure the oil level in an automatic transmission.

Significant wear of the automatic transmission, as well as clogged oil channels, also causes the car to jerk at all speeds.

The car is shaking, what should I do?

At the first stage, the machine is diagnosed. Let's say that you have a VAZ 2106 with a carburetor engine in your garage. Your car already shows signs of “illness” at the first stage of movement. Or the car started moving without any hassle, but when a certain number of revolutions was reached, the engine malfunctioned. All this will not give answers, but only creates questions, because anything can break. In any case, if unstable operation of the car’s power unit is noticed while pressing the accelerator pedal, the first thing you should do is:

Check air and fuel filters. The supply of air and fuel to form a combustible mixture will be difficult if these elements are heavily contaminated.
Check the fuel pump. Its incorrect operation leads to unstable fuel supply.
Check fuel pressure. The supply of the fuel-air mixture under insufficient pressure often leads to jerking of the car. The pressure when the engine is running should not exceed 3 kgf/cm2.

Most of the reasons lie in the car's fuel system. But you shouldn’t write off the ignition system, and sometimes even the transmission can cause discomfort while driving. There can be many reasons. To narrow your suspicions, measure the conditions during which the car begins to act up. To do this, while driving, watch the instrument panel and remember at what moment the uniform movement stopped. Do this several times to confirm that your observation is correct.

Features of pillows

On Lada-2109 cars, airbags are used, the functioning of which has the following features:

There are many designs of supports, they are able to reduce the level of vibrations, therefore, during production, all values of the loads that act on them are taken into account. These components are constantly under load, and their direction and magnitude changes many times.

The only constant load is the mass of the engine itself. But during the start of movement, several other forces arise, acting in different directions. When reversing, the same forces act on the airbags as when starting, but they are directed in the opposite direction.

During sudden acceleration, braking, or driving over uneven surfaces, a lot of forces are necessarily exerted on the engine mounts. In the manufacture of cushions for Lada-2109 cars, only natural rubber is used, as well as high-grade rubber. In addition to rubber elements, the supports consist of steel frames and heavy-duty adhesive. They work at temperatures of -40. +70 degrees.

Why does the car jerk while driving?

The situation when a car starts to move unevenly is familiar to every motorist. The problem, which manifests itself in jerking and jerking, can be caused by the incorrect operation of various automotive systems. Today we will look at the common symptoms of this “disease” and share recommendations for eliminating them.

So, a violation of the smoothness of the ride and the associated jerks of the car occur:

when starting off;
during acceleration;
at low speeds;
when the engine is operating at maximum load;
in transient conditions;
in all of the above cases.

Determining the culprit of the malfunction

The car can “twitch” while driving for various reasons, so you should adhere to a certain troubleshooting algorithm. If there are no obvious signs of transmission malfunction, then first of all we check the power and ignition system.

Failures in the engine power system

Malfunctions in the system for preparing and supplying the fuel mixture are indicated by jerking of the machine in motion. In this case, the malfunction can manifest itself in different ways:

The car begins to twitch when the accelerator pedal is pressed sharply. At the same time, instead of gaining speed, the engine runs jerkily, and therefore the car picks up speed very reluctantly. At some stage, the twitching stops and the engine “picks up.” In other cases, the power unit stalls when the throttle is maximally open, or jerking occurs when the gas is released.
The unevenness of the ride appears unexpectedly - when the car is moving at a constant speed, in a stable speed mode.

As you can see, uneven engine operation can appear both when the crankshaft speed changes sharply or smoothly in one direction or another, or when operating at stable speeds. The reason for these phenomena is a simple lack of combustible mixture, due to which the engine simply cannot develop power sufficient to overcome the resistance of the transmission.

To eliminate negative phenomena, we check several main components of the power system:

1. Filter. Even with a working fuel pump and a clean fuel line, the engine will begin to starve if the fuel filter is clogged with dirt. The way out is to replace or clean the filter element - it all depends on where exactly the blockage occurred. The fact is that car engines have several cleaning elements installed along the fuel path. If you are dealing with an injection internal combustion engine, then you should pay attention to the third filter element located after the fuel pump. Designed to separate the smallest particles, it clogs quite often, which is why the gas pump cannot pump the required volume of fuel through it. For carburetor cars, we check both the third filter installed in front of the carburetor, and the second one - it is located between the fuel tank and the fuel pump. If replacing them did not yield anything, then you should check the coarse filter installed on the fuel receiver. In addition, the cause of insufficient fuel supply may be the mesh located in front of the float chamber in the carburetor body.

2. Throttle assembly . Malfunctions in the throttle can be caused by wear and damage to its parts and contamination. And if the first requires serious repairs, then in the second case, simple cleaning of the throttle assembly elements mechanically will help. In the case of carburetor internal combustion engines, the situation is more complicated, because you will have to completely disassemble the carburetor and clean all channels, jets, diffusers, etc.

What causes the car to jerk when running at low speeds?

Since the car begins to twitch when reaching even low speeds, it will not be possible to immediately identify one specific problem. Problems may be hidden:

In the engine fuel mixture supply system;
In the vehicle ignition system;
At the checkpoint;
In the distributor design;
Includes fuel filters;
In the sparking system;
In the control unit of the vehicle's on-board computer.

Let's go through the faults in each of the listed systems in detail.

Tip: When detecting a “jerking” behavior in the vehicle, the brakes may also squeak when braking. These 2 problems can be either interrelated or indicate completely different breakdowns.

Checking the engine fuel mixture supply system

Often the reason that the car jerks at low speeds is due to a malfunction of the power system. When the car starts to move, the cylinders simply cannot receive the required amount of fuel mixture, as a result of which the car is unable to transfer the required amount of power to the chassis for smooth driving and smooth commissioning of the transmission. As a result of increased pressure and transmission resistance, uneven running of the machine appears.

To solve this problem, it is recommended that you first pay attention to checking the throttle body. It also wouldn’t hurt to test and diagnose the performance of the sensors installed in the system for determining idle speed indicators. Do not forget to check the serviceability of the throttle valve position and the mass air flow sensor.

Throttle body

During diagnostics, most often a breakdown is found in the injectors responsible for uniform injection of the fuel mixture. In rare cases, engine jerking problems may be related to the air ducts that connect the injector receiver to the air filter structure. Here the problem lies in depressurization of connections and loss of pressure.

The solution to the problem is to replace all faulty components yourself or with the help of car service specialists. After repair, it is recommended to ensure that all connections are in good working order and that there is no loss of pressure in the fuel line system that is connected to the fuel pump itself.