Why are there multiple misfires on the VAZ 2114?

Error code P0300 indicates a violation of the ignition order, which stands for random multiple misfires in the cylinders; in English, the diagnostic tool displays: “Random cylinder misfire detection system.” If a misfire is detected in a specific cylinder, then the last digit “P030x” will change to 1, 2, 3, 4 and so on up to 6 or even 12, depending on which particular “pot” the misfire is in. So error P0300 is derived from errors such as P0301, P0302, P0303, P0304. Most often they occur due to a lack of spark, a fuel supply failure or problems with the exhaust gases.

Error P0300

Let's look at the list of possible causes of misfires, why error p0301, error p0302, error p0303, error p0304 or others of this kind appears, the consequences and methods of elimination, in more detail.

What causes misfires

Occurrence is a real problem that can become a prerequisite for more severe consequences. The car not only jerks, jumps and cannot work at full power. But it also starts with great difficulty; when driving, characteristic popping noises are heard, which occur due to detonation of the combustible mixture in the problem cylinder.

Checking the operation of the cylinders on a VAZ 2114 using computer diagnostics helps to detect many errors. If error P0301 lights up, then this indicates problems in the first one, if P0302 means misfires were detected in the second one.

Code 0302 - errors in the second cylinder

The VAZ 2114 electronic control unit continuously monitors the operation of the power unit through sensors. In this case, the rotation speed of the sensor on the crankshaft and the cylinders involved in a certain period of time is estimated. When a misfire occurs, the crankshaft rotation speed slows down slightly and this is determined by the computer. Modern electronics, if a miss is detected and the specified interval is exceeded, turns off the problematic cylinder. It simply will not receive fuel.

The cylinder can be turned on after a certain time, or after the engine is restarted. No more than 2 cylinders can be turned off at the same time. This is enough to get to the service station and keep the catalyst intact. On early versions of controllers, errors very often occurred when misfires were detected when driving on a bad road. However, now on the VAZ 2114 this problem has been completely solved after installing a road quality sensor.

VAZ 2114 car engine

The difficulty in identifying this malfunction lies in the fact that the misfire is not constant, but appears periodically. It often happens that in cold weather (until the engine is warmed up) it “troubles”, but after warming up, it starts working normally. This occurs due to wear of the cylinders, because after warming up, the metal parts expand and compression is restored.

Often, at idle speed, the VAZ 2114 power unit functions perfectly, but when the load increases, it throttles and functions with noticeable interruptions.

The problem is a burnt-out gasket, as a result of which, when the pressure in the combustion chamber increases, a leak appears.

The combustion chamber

It happens that 2114 “coughs” for a little while, and then its work returns to normal again. In this case, nothing definite can be recommended, because a complete check of the power unit is required. There may be various reasons.

Engine operation with misfires

Previously and now, most engines (including those for the VAZ-2114 - approx.) were equipped with four-cylinder engines, and at the moment when even one of them began to fail, the car began to behave unstably, and power could drop down to 25 % .

This engine trembles when starting

This behavior of the motor was called “tripping” the engine, which is popular and known even now.

Nuances in the misfire problem

If a problem such as a misfire occurs in your car, you still shouldn’t delay solving it, as this can lead to much more serious consequences. At first, innocent, difficult engine starts can develop into extreme moments of engine operation associated with constant detonation of the exhaust system from a non-burning mixture .

Important nuances

If misfires occur on a VAZ 2114, this is a fairly serious problem that can develop into more serious consequences. At first the car jerks, then misfires occur, and full power is not used.

Swimming revs

It will be difficult to start the car, and over and over again the detonation noise of the air-fuel mixture will occur in the idle cylinder.

Cylinders can be checked using computer diagnostics. This method produces the corresponding errors in the form of codes. Using them it is already easy to determine which cylinder has problems. For example, if there is a misfire in cylinder 2 on a VAZ 2114, then the error code will look like P0302.
The electronic control unit, that is, the ECU, regularly monitors the operation of the power unit using the appropriate sensors installed on the VAZ 2114. In the case of misfires, the ECU estimates the rotation speed using the crankshaft sensor. If there is a misfire in cylinder 4 on a VAZ 2114, at a certain moment the crankshaft will rotate more slowly, which will be determined by the computer.
Modern electronics make it possible to automatically turn off a cylinder that has problems. In other words, the fuel supply to it stops.
The cylinder may return to operation after some time, or after the engine is restarted.
No more than two cylinders can be switched off at the same time. For your “fourteenth” model, two cylinders are enough to get to the garage or the nearest service station, thereby keeping the catalyst intact.
In early versions of the VAZ 2114, the electronics generated errors about omissions if the car was moving on bad roads. On updated versions, this problem was eliminated by installing a road surface quality sensor.
Misfires are not always easy to determine, since this phenomenon is not constant and can occur periodically on the VAZ 2114.
Car owners often make mistakes in winter, when the engine starts to throttle when warming up, and then, when warmed up, it works normally. This phenomenon occurs due to wear on the cylinders, since when warmed up the metal elements expand and the system returns to normal operation.
If the VAZ 2114 engine runs normally at idle, but when the load increases, it starts to stall or operate unstably, the cause should be sought in a burnt gasket. Because of this, pressure increases inside the combustion chamber and a leak occurs.
When the engine coughs a little, but soon returns to normal operation, it becomes difficult to determine the cause. This will require a full diagnosis.

Is it safe to drive with a misfire?

If a leak occurs, the air-fuel mixture entering the engine will come out unburnt. Modern cars have a catalytic converter that reduces emissions from the car. The catalyst during operation can have a temperature of up to 600 degrees. And what happens when the unburnt air-fuel mixture gets into it? That's right, it will explode inside the catalyst. Explosions inside the catalytic converter can damage it. And a new catalyst is not a cheap pleasure.

In addition, misfires can also damage other sensors in the engine, such as oxygen sensors. We would never recommend driving a vehicle with a misfire, especially over long distances. Short distances to a service station without stress on the engine are normal, but don't ignore gaps and continue driving.

Basic faults

Due to the extensive accumulated experience in repairing this malfunction, we can identify common factors that are inherent to any units. Common reasons that can lead to misfires in the ignition system:

First of all, the problem may lie in the candles. Increased or decreased clearance, carbon deposits. Low quality candles. Candle with soot
Wiring problem. Mechanical damage. Oily contact.
Damage to the module itself or the ignition coil.
Due to poor quality fuel, the injectors may become clogged.
Compression in the cylinder is broken. Compression dropped
Incorrect adjustment of the gas distribution mechanism.
Air leakage into the fuel system due to various factors. Damage to the intake manifold, wear of the injector rings.
For various reasons, the gap between the cylinder and the piston has decreased.

These are the main factors that are most common.

On cars without a computer, checking and identifying the cause occurs by trying different options.

Once the cause is identified, we move on to repairs. For these works you will need the help of a specialist.

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Error p0300, p0301, p0302, p0303 and p0304 causes

Unfortunately, the diagnostic tool has not learned to determine the specific cause of the failure and, in this case, misfire in the engine cylinder, but, fortunately, the most likely malfunctions can develop in two directions - either there is nothing to burn , or it is impossible to ignite . Although it is still too early to rejoice at the possible quick search for the cause of error p0300, since it could be:

Cylinder misfires. How to diagnose the cause.

In the ignition system

spark plug failure;

breakdown of a high-voltage wire;

faulty ignition coil (or module);

other reasons related to wiring and connectors in the ignition system.

In the power system

poor quality fuel;

clogged injectors;

heavily contaminated fuel filter;

low fuel pressure.

The main reasons why error P0300 occurs

Common faults

Let us immediately note that the problem with omissions that arise should only be solved at specialized service stations. You can identify the problem cylinder yourself. But after this, you should go to a car service center and, using computer diagnostics and appropriate measures, fix the breakdown.

Diagnostic program

There are several reasons why such a phenomenon as misfires in the ignition system occurs on the VAZ 2114.

Problem candles. If carbon deposits appear on them, the gap decreases or increases, they will not be able to work properly. As a result, there are misfires in the cylinders. Quite often, spark plugs do not work for the simple reason that the car owner decided to save money and buy spark plugs of dubious quality. You should not count on their long service life and reliable operation.
Wiring problems. Here you most often have to deal with wire wear, chafing, and mechanical damage. Sometimes the problem is solved by replacing the wiring. But in some cases, wiring can negatively affect the functionality of the devices it goes to. As a result, both the wiring and the device must be replaced.
Contacts. Contacts may burn out, become covered in oil, or rust. Cleaning them or completely replacing them may help. The second option is preferable in order to reduce the risk of omissions occurring after a short period of time.
Damage to the ignition coil or module. If you have a VAZ 2114 with a 1.6-liter engine, you are dealing with a coil. Owners of the newer version with a 1.5-liter engine are already solving problems with the ignition module. Regardless of this, units often fail and cause leaks. There is no point in repairing them, so it is better to immediately replace them with new ones.
Use of low-grade fuel. The problem for many owners of domestic cars is that they, sometimes unknowingly, doom themselves to constant repair work. A trivial example is the use of cheap gas stations. Low-quality gasoline produces a poor air-fuel mixture, clogs filters, and clogs injectors. This often causes misfires in the cylinders. The right solution is to fix the problem and start using good gas stations. Their gasoline is more expensive, but you will spend many times more money on repairs if you don’t stop refueling with God knows what.
Omissions. They also often occur due to impaired compression in the cylinders. This fault should be checked almost first.
The gas distribution mechanism is not adjusted correctly. Its adjustment will not take much time; the work can be done with your own hands.
Excess air enters the fuel system. This may occur due to damage to the intake manifold, wear of the rings on the injectors and other defects. Therefore, you should check the system for leaks and find sources of air intake.
The gap between the piston and cylinder has decreased. There may be many reasons for this, but you will definitely have to check them if this is the reason.

The essence of eliminating cylinder misfires is to step-by-step check the causes of malfunctions. It could be anything from the list presented, or something rarer. That is why it is better to entrust the work to specialists, since it will take a lot of time to independently check each component of the fuel system and ignition system. Moreover, it is not a fact that you will eventually find the reason for the engine malfunction.

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Misfires in cylinders 1 and 4 of the VAZ 2114: we analyze the problem

A car engine is a rather complex unit in terms of design; its stability, power and service life depend on the uninterrupted functioning of individual parts and the absence of breakdowns.

One of the most common engine malfunctions is the appearance of misfires: they lead to a drop in engine power and the car becomes uncomfortable to operate.

Today we will figure out how to determine the causes of misfires and how serious the consequences can be.

There are many reasons for misfires, these include the following phenomena:

Poor quality of the fuel mixture is often the cause of lack of ignition in the cylinders; misfires are associated with a lean or, on the contrary, excessively rich composition.
Problems with candles. The wrong gap may be set, it may happen that the spark plug is damaged by the appearance of carbon deposits, all this leads to a weak spark formation.
Low compression in the cylinder (determined using a pressure gauge).
Incorrect operation of the distributor distributor element or ignition module.
Failure of the fuel pump, and as a result low pressure in the fuel rail.
Inoperability of one or more injectors.

To find the cause, first of all, you need to check the composition of the fuel-air mixture and the quality of the fuel. If low-quality gasoline or diesel is poured into the engine, sediment may clog the injectors, and as a result, the ignition will not work properly.

Problems associated with low-quality fuel are especially common in cars with injection engines.

As a result of clogged injectors, the engine misfires constantly under load, periodically when idling and during a cold start.

The system itself may be faulty: in such cases, misfires can occur due to problems with spark plugs, wiring, and other elements. As a preventative measure, you need to inspect all the main ignition systems, namely: Ignition coils, armor wires, and spark plugs.

It happens that cracks form in one of the ignition coils due to temperature changes, and it begins to short-circuit to the housing; therefore, the spark does not reach the spark plug, or only does so only once in a while.

Another phenomenon that leads to breakdown is a lean or enriched mixture. If the composition is excessively saturated with oxygen or a flammable substance, the proportions are violated and ignition occurs too early or, on the contrary, late. Problems in the power system in this case are explained by faulty injectors, air leaks at the inlet, or the need to replace the air filter.

Also, an incorrect mixture in the engine can be a consequence of poor-quality chip tuning. Because chip tuning is essentially changing the factory mixture calibrations, using special equipment, to a richer or leaner mixture.

If one or more engine cylinders have poor compression, this may cause a misfire.

In order to ignite and burn in the cylinder, giving all its energy to the piston, the fuel-air mixture must be compressed in the cylinder. But this will not happen if the cylinder is not sealed during compression.

Misfire in the cylinders is an unpleasant phenomenon in itself, which also threatens the emergence of more serious problems. If the system works intermittently, and the owner is in no hurry to get service, he will have to face the following consequences:

Increased fuel consumption.
Increased toxic emissions that are hazardous to the environment and human health.
Engine power will decrease significantly over time.
The motor will be too noisy.

If a malfunction occurs in the form of a misfire, it is better to have it checked and repaired as soon as possible. If you can’t find and fix the problem yourself, it’s better to contact a car service center.

Other reasons

In addition to the main reasons leading to the problem, a defect can occur due to other phenomena:

Mechanical breakdowns of the engine, if there are malfunctions in the operation of the internal combustion engine due to impaired gas exchange or the operation of the crankshaft. Diagnosing the problem is more complicated; this requires disassembling the unit.
Damage to any tooth or several teeth of the damper, destruction of the rubber damper gasket, “beating”. These effects lead to incorrect calculation of acceleration and ignition periods.
Coolant entering the system. It is necessary to check the cylinder for foreign matter.
The wires are damaged, they carry too low or, conversely, high voltage.

To check, a special diagnostic tool can be used, which is connected to the car via the OBD II connector. According to a special diagnostic program, error P0300, P0301 or P0304 may appear. Error code 300 is the most common; it indicates that there are multiple misfires; the corresponding check light lights up on the dashboard.

Also, in modern diagnostic programs, there is an ignition coil test mode. The essence of this test is that the program turns off each coil one by one, and thereby it becomes clear which coil is working and which is not. After all, if the program turns off the ignition on an idle cylinder, then nothing will happen.

On some cars that have an on-board computer installed, errors, including misfires, can be read from it.

If the misfire code is 301, we are talking about a problem with the first cylinder, 303 with the third.

If it is not possible to diagnose the engine with an OBD scanner, and there is no on-board computer, then you can diagnose the leaks the old fashioned way.

To do this, you need to open the hood, and with the engine running, one by one remove the armor wires from the spark plugs. If, when the wire is disconnected, the engine begins to stall and choke, then the spark plug is working; if nothing happens, then this indicates that the spark plug is not engaged and the cylinder is not working.

This method is only suitable if there are constant misfires on the cylinder, but if they occur periodically, then this method will not work.

Sometimes motorists are faced with such an unpleasant phenomenon as the car jerking at the moment of starting, while the car itself practically does not move. The reason for this “behavior” is the misfire of the VAZ 2114. We will talk about why they occur, as well as how to eliminate them, in today’s article.

VAZ 2114 misfires

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Misfires themselves are common to all four-stroke engines, from the oldest to the most modern. About this, most often they occur on any one cylinder, as a result of which only 3 cylinders remain in operation.

This phenomenon, well known to many drivers, is called “triple movement”. At the same time, the motor operates unevenly, with frequent jerks, and the overall power drops by more than a quarter. In addition to problems on one cylinder, misfires also occur in cylinders 1 and 4 of the VAZ 2114. This situation is much more critical and requires an urgent solution.

If you notice misfires on your car, you should stop driving it as soon as possible and carry out repair work. It is impossible to continue operating such a vehicle without troubleshooting, since initial problems with starting can develop into constant jerking caused by fuel detonation, and even engine failure.

Speaking about omissions, it is important to note that sometimes car enthusiasts mistake completely different malfunctions for ignition system problems, namely:

slight tripping of the car after starting in the cold season. It is caused not by ignition errors, but by cylinder wear. After starting, the cold elements of the engine begin to heat up and, as a result, expand. These changes in size cause “tweaking”;
car tripping when suddenly adding gas at idle. This phenomenon is also caused not by poor ignition, but by damage to the cylinder head gasket, through which a leak occurs;
engine tripping due to poor fuel.

Thus, to accurately determine the cause of the tripping, it is best to carry out diagnostics - this will help to ensure that false versions are rejected and immediately begin to fix the problem.

Diagnostics

To accurately detect misfires on cylinders 1 and 4 of the VAZ 2114, it is necessary to perform computer diagnostics. It is carried out using a special electronic module connected to the diagnostic connector. After starting the scan, the computer will automatically produce results in the form of special codes corresponding to certain errors.

In this case, the last digit in the code corresponds to the number of the faulty cylinder. For example, misfire in cylinder 1 of a VAZ 2114 will be designated as P0301 and so on

There are quite a few reasons why omissions may occur, namely:

Different compression in different cylinders. This is one of the most common reasons why misfires occur during engine operation, so you should check it first;

Compression of cylinders VAZ 2114

faulty spark plugs. There may be a number of reasons for this - from the resulting carbon deposits to the actual bad spark plugs. To solve the problem, you can try to restore (for example, clean) existing spark plugs or completely replace them with new ones;

An important rule to remember here is that you should always replace a complete set of spark plugs (4 pieces), even if only one is faulty. There is no need to skimp on engine performance.

wear of armored wires or their breakage. Despite the high protection of high-voltage wires, during the operation of the vehicle they also wear out - their outer sheath becomes thinner and even breakdowns may occur. In order to check the condition of the armored wires, you should measure their resistance using a megohmmeter and compare it with the number indicated on the shell. If they are approximately the same, then the wires are in good condition, if not, then they should be replaced with new ones of a similar type;

Checking high-voltage wires with a tester

faulty electrical contacts. So, if misfires are observed in the 4th cylinder of a VAZ 2114, then it is worth checking all the contacts used to connect electrical equipment to this cylinder. If there are oxides or other contaminants, the contacts should be wiped with kerosene and cleaned with fine sandpaper;
incorrect operation of the gas distribution mechanism. In order to detect it, you should inspect the timing belt and determine whether the marks of the upper and lower points coincide. If they match, then the mechanism is working properly, but if not, then they should be combined (in this case, it is highly advisable to replace the drive belt itself). When installing the belt, one should not forget about its correct tension - it is one of the main conditions for the correct operation of the gas distribution mechanism;

Camshaft and head marks

failure of the ignition module. Despite its high reliability, the module can still break, as a result of which normal operation of the ignition system becomes impossible. You can determine its performance either for external reasons - by the presence of mechanical damage or deep corrosion, or by replacing it with a new one and checking the operation of the engine. If it turns out that the ignition module is damaged, then only replacement can help, since it is almost impossible to repair it;
use of low quality gasoline. Of course, no car enthusiast will deliberately pour bad fuel into the tank of his car. But today's realities are such that the quality of gasoline sold at gas stations does not always correspond to what is declared. The use of such fuel first leads to clogging of the filters, and then of the injectors, as a result of which the normal injection of the mixture into the cylinders stops and misfires begin. You can avoid such a nuisance by using only proven fuel stations;
air entry. Excess air sucked into the system leads to a lean mixture and engine malfunctions. In order to find the place of its penetration, you will have to inspect the entire air intake system and check the condition of the o-rings.

How to detect a malfunction?

For owners of cars with smart hardware, the task of detecting a problem is greatly simplified. The electronics generate error codes indicating a faulty cylinder.

Cars with and without an ECU need to be checked differently.

Car with ECU

We connect the scanner and start deciphering the error codes

If the code contains an indication of a specific cylinder, you need to pay attention to it first. The problem may be in the spark plugs or in the wiring connected to this cylinder

It's worth checking the gaskets. If error P0300 appears, check the fuel filter and the quality of the fuel mixture used. The reading on the P0204 device indicates damage to the injector.

Many cars, even those made in Russia, are now equipped with electronic units. If the ECU does not work correctly, it is better to replace it. The new “intelligence” must be compatible with the car model. Electronic units can also be installed on old VAZs.

Car without ECU

Finding the source of the problem in cars without an ECU is much more difficult. As a rule, misfire occurs in several cylinders at once. Here, manual checking of the mechanisms is indispensable. First of all, you need to inspect the wiring and spark plugs. The armored wires are checked using an ohmmeter. If the readings are too low or too high, the wiring will have to be replaced. If the readings are normal, you need to measure the compression in the cylinders.

The problem may be with the fuel pump. But if everything is in order with it, you will have to remove the valve covers to determine the condition of the cylinders, piston rings and the valves themselves. In some engines, the valve springs are “buried” deeply. To inspect them, you have to dismantle the cylinder head.

In cars without an ECU, the problem cannot always be detected independently. Inexperienced drivers often have to contact service centers.

Recommendations for checking and troubleshooting

The first thing you should check when misfiring is the explosive wires and ignition coils (module), they often turn out to have broken insulation, a break, or an oily surface. We measure the wires with a multimeter (normal resistance is about 4 - 10 kOhm), in resistance mode, but to check individual ignition coils, you just need to swap places with a known working cylinder and clear the errors again. If the code has changed to the number of another cylinder, then the coil is faulty. The ignition module is more complicated; it needs to be checked with a tester.

The second in line are the spark plugs - a damaged electrode, incorrect gap, or oil deposits lead to failure or unstable operation of the spark plug.

Having unscrewed the spark plug for inspection, then what else can be done - measure the compression in the cylinder . Reduced or absent compression leads to insufficient compression, and therefore creates problems with ignition of the mixture.

Clogged fuel injectors provoke interruptions in the supply of fuel to the combustion chamber, but, unfortunately, without a stand it will not be possible to quickly check them. And the only thing that can be recommended in such a situation is to refuel with fuel with a higher octane number, and drive the car for some time at high speeds (4-5 thousand/rev).

Common faults

There are several reasons why such a phenomenon as misfires in the ignition system occurs on the VAZ 2114.

Problem candles. If carbon deposits appear on them, the gap decreases or increases, they will not be able to work properly. As a result, there are misfires in the cylinders. Quite often, spark plugs do not work for the simple reason that the car owner decided to save money and buy spark plugs of dubious quality. You should not count on their long service life and reliable operation.
Wiring problems. Here you most often have to deal with wire wear, chafing, and mechanical damage. Sometimes the problem is solved by replacing the wiring. But in some cases, wiring can negatively affect the functionality of the devices it goes to. As a result, both the wiring and the device must be replaced.
Contacts. Contacts may burn out, become covered in oil, or rust. Cleaning them or completely replacing them may help. The second option is preferable in order to reduce the risk of omissions occurring after a short period of time.
Damage to the ignition coil or module. If you have a VAZ 2114 with a 1.6-liter engine, you are dealing with a coil. Owners of the newer version with a 1.5-liter engine are already solving problems with the ignition module. Regardless of this, units often fail and cause leaks. There is no point in repairing them, so it is better to immediately replace them with new ones.
Use of low-grade fuel. The problem for many owners of domestic cars is that they, sometimes unknowingly, doom themselves to constant repair work. A trivial example is the use of cheap gas stations. Low-quality gasoline produces a poor air-fuel mixture, clogs filters, and clogs injectors. This often causes misfires in the cylinders. The right solution is to fix the problem and start using good gas stations. Their gasoline is more expensive, but you will spend many times more money on repairs if you don’t stop refueling with God knows what.
Omissions. They also often occur due to impaired compression in the cylinders. This fault should be checked almost first.
The gas distribution mechanism is not adjusted correctly. Its adjustment will not take much time; the work can be done with your own hands.
Excess air enters the fuel system. This may occur due to damage to the intake manifold, wear of the rings on the injectors and other defects. Therefore, you should check the system for leaks and find sources of air intake.
The gap between the piston and cylinder has decreased. There may be many reasons for this, but you will definitely have to check them if this is the reason.

Misfire in a VAZ Priora cylinder, signs, causes

Almost every motorist has encountered the problem of flammable mixture ignition. There can be many reasons for problems when igniting a combustible mixture, but they all lead to a drop in engine power and the shutdown of one or a pair of cylinders. On cars with an ECU, when the engine malfunctions, errors appear that indicate problematic parts of the unit. If misfires occur, you should urgently contact a service station to troubleshoot the problem.

Unstable engine operation and shaking at idle, loss of power and increased fuel consumption, the appearance of a “Check” error on the instrument panel, jerking of the car and other troubles can be caused by a misfire in the engine cylinder.

There is nothing wrong with this, because if the engine runs but does not pull, it means that not everything is so critical.

Next, we will talk about how to properly diagnose a car and identify the cause of the malfunction.

There can be many reasons for the problem; even professional mechanics spend more than one hour to identify its source.

The main reasons for misfire in cylinders 1, 2, 3, 4 can be:

The ignition coil or module has failed;
Inoperative fuel injector, clogged due to low-quality gasoline;
Incorrect spark plug gap, which can lead to poor sparking;
The spark plugs are flooded or carbon deposits have formed on them;
Breakage of high-voltage wires, increased resistance (non-standard ones are installed), oiliness of contact points;
A high-voltage wire has fallen off (often happens on Lada Kalina and Granta);
On an 8-valve engine, the timing belt may jump (during replacement, an error was made due to marks or as a result of excessive wear);
On a 16-valve engine, the hydraulic compensators are not working correctly;
Air leak (can be anywhere);
The compression in the engine cylinders has dropped or is different (applies to cars with high mileage);
Low pressure in the fuel rail as a result of reduced fuel pump performance.

If your car is equipped with a modern control unit, then this greatly simplifies troubleshooting; otherwise, you will have to use time-tested old-fashioned methods.

By connecting the computer to the car, you can find out in which cylinder, 1, 2, 3 or 4, and for what reason there are misfires, for example, the ignition coil or one of the injectors has failed.

But in any case, before going to a car service center, you need to check the condition of the spark plugs, injectors, high-voltage wires, how the exhaust system works, and whether there is smoke from the exhaust pipe.

The scanner is connected to a special connector, which can be located in different places in each car model, but it has one function: diagnostics.

Next, error codes are read from the control unit and decrypted.

For example, VAZ 2110, 2114, 2115, Lada Kalina, Priora, Granta cars have the following error codes that are characteristic of misfire:

P0300 - a large number of misfires;
P0301, P0302, P0303, P0304 – misfires in cylinders 1, 2, 3 and 4, respectively;
P0300 - a large number of misfires in a random order;
P0301, P0302, P0303, P0304 – misfires were detected in 1, 2, 3 and 4, respectively;
P0363 – see point 4, the fuel supply to the problem cylinders is stopped;
P1301, P1302, P1303, P1304 – respectively, misfires dangerous for the catalytic converter were detected in cylinders 1, 2, 3, 4;
P0300, P0301, P0302, P0303, P0304 – detection of misfires affecting the toxicity of exhaust gases;
P0363, P1301, P1302, P1303, P1304 – the same as in point 7, but affecting the catalyst;
P0351, P0352, P0353, P0354 – open circuit in the ignition coil in the control circuit 1 (1-4), 2 (2-3), 3, 4;
P2301 P2303 P2305 P2307 - short to on-board network in the coil in the control circuit of cylinders 1 (1-4), 2 (2-3), 3, 4;
P0201, P0202, P0203, P0204 – respectively, open circuit for controlling injectors 1,2,3,4;
P0261, P0264, P0267, P0270 - short circuit of the injector control wires to the body, respectively, in the 1st, 2nd, 3rd, 4th center;
P0262, P0265, P0268, P0271 – the same as point 12, but only to the on-board network;
P1500 – electric fuel pump relay, wire break.

Let's look at misfires using the example of the VAZ 2109, 2110, 2114, 2115, Kalina, Priora, Granta models.

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The computer generated error P0303 (misfire in 3rd crank).

First you need to understand how the ignition coil works. It consists of two small coils, pins 1 and 4 are connected to the first, and pins 2 and 3 to the second.

Those. during operation, voltage is simultaneously supplied to the first and fourth cylinders or to the second and third.

We have misfires in cylinder 3. Remove the wires from 2 and 3 and swap them.

High-voltage wires are tested by checking their resistance. To do this you need a regular multimeter.

Set the resistance measurement mode to 20 kOhm.

In our case, we check the third wire. If the device shows numbers within the range of 3.5 - 10 kOhm, then the wire resistance is considered normal, otherwise it changes.

Next we check the coil. For this you also need a multimeter.

We measure the resistance between 1 and 4 and 2 and 3 coil terminals. Readings of 10 kOhm, or around this figure, are considered standard.

Next we check the resistance between each terminal and ground. In this case, on the contrary, the multimeter should show 1 (infinity).

If resistance is shown at one of the terminals, it means that its insulation is damaged and it is connecting to ground. Accordingly, the required voltage will not be supplied to form a spark.

Next, we check the resistance between the central terminal of the ignition coil and the housing (ground). It should also be equal to infinity, i.e. 1.

A resistance of 2 ohms is considered normal (-). There should be no break between the extreme terminals.

Next, check the condition of the contacts on the coil itself and on the wires; they tend to oxidize over time, especially if your region of residence has a humid climate.

If the error remains in cylinder 3, but the coil and high-voltage wires are in good condition, we check the spark plug.

The easiest option is to remove the spark plug from the working cylinder and swap them.

If the error then transferred to another cylinder, then most likely the issue is in the spark plug.

If nothing has changed and the error remains, then check the injectors.

Next, check the injector power supply circuit. Also, the injector may become clogged and not supply the required amount of fuel, which can cause misfires. Therefore, you will have to clean the injectors.

If after all the above checks the misfires have not disappeared, you need to check the valve clearances.

The valves should not be tightly clamped, as this will lead to their incomplete closing, and this, in turn, will lead to a decrease in compression and compression ratio in the cylinders and this will cause misfires. Also, if you press too hard, the valve may burn out.

READ ON THE TOPIC: Other characteristic malfunctions of the VAZ 2110 and other cars in the series.

If we talk about foreign cars, they also have special error codes indicating misfires.

Let's look at the error codes using the example of a BMW x5 e53 motor M54 3.0 USA (if the country of manufacture is different, the codes may differ).

As a rule, these errors are associated with problems with mixture formation, sparking and decreased compression:

Problems with the ignition coil - errors 101, 202, 303, respectively, cylinders 2, 4, 6;
Injector circuits – errors 505, 606, short circuit, open circuit;
Injector - codes 2216, 2317, 2418, 3321, respectively, refer to cylinders 3, 6, 4, 5;
Malfunction of the idle air control valve - 271V;
Ignition coil - errors 291D, 301E, 311F - 1, 3, 5 ts.
Problems with the camshaft position sensor - error code 6541;
Fuel pump relay - error code 6945;
Problems in the ignition system - 210D2;
Failure of the idle air control valve as a result of its mechanical damage - 211D3;
Poor quality fuel mixture - 227E3 for cylinders 1, 2, 3 and 228E4 for 4, 5, 6.
Cylinder misfires - 238EE in the first, 239EF in the second, 240F0 in the third, 241F1 in the fourth, 242F2 in the fifth, 243F3 in the sixth;
Weak flow in the air mixing system - 245F5 cylinders 1, 2 and 3. Error code 246F6 - 4, 5 and 6 cylinders.

Also, the reasons for misfire in a BMW x5 e53 M54 engine can be:

Air leakage, for example, the throttle corrugation or other suction points are torn;
The mass air flow sensor has failed;
Incorrect operation of hydraulic compensators;
Timing chain stretching and ignition timing deviation;
The high-voltage coil of one of the cylinders has failed (rearrange it to check);
The problem is in the flow meter, remove the terminal block from it and see how the engine works;
If the BMW x5 e53 has misfires after 3000 rpm, then check the DIS (DISA - installed inside the intake manifold, designed to suck in the fuel mixture through separate pipelines);
A failed membrane is responsible for the mixture of gasoline and air;
Other reasons.

What are cylinder misfires?

A misfire is a malfunction of the engine when the mixture of fuel and air in one or more cylinders does not ignite in a timely manner or does not ignite at all. As a result, the operation of the internal combustion engine according to the specified clock cycles is disrupted, the engine begins to “trouble” and jerk, and power is noticeably lost. Unburned fuel from an idle cylinder enters the exhaust system and burns there. For this reason, misfires may additionally be accompanied by popping noises and shots in the muffler.

Let's start with the fact that if there are problems with ignition of the mixture on an engine with a carburetor, the main signs are: “triple” of the engine, lumbago in the exhaust system, loss of power, as well as a distinct smell of fuel from the exhaust pipe.

In the case of an injector, similar symptoms may appear, while a check light often lights up on the dashboard of an injected car, and misfires are recorded in the ECU as an error. All this means that the driver needs to conduct computer diagnostics of the engine.

Let us add that after the control unit detects such omissions, the ECU can also forcibly turn off one or even two problem cylinders. This happens after the control unit analyzes the DPKV readings, taking into account the rotation speed of the crankshaft and the cylinders operating at that moment. Measurements are taken every quarter turn (on engines with 4 cylinders).

The misfire counter turns off the non-firing cylinders after the permissible misfire threshold is exceeded. Shutdown means stopping the fuel supply. The cylinder is then reactivated after a programmed period of time or after the engine has restarted.

This solution was created in order to protect the catalytic converter in the exhaust system, which is equipped with injection cars. The fact is that the ingress of unburned fuel from idle cylinders destroys the catalyst. Eliminating cylinders that have misfires from operation allows you to drive to the service station under your own power, with minimal damage to the catalyst.

It should be added that even if the problem arose one-time, that is, it is not systematic, in some cases it is not possible to extinguish the burning check using simple methods (for example, removing the terminal from the battery). In other words, the check light is constantly on, and the engine error can only be reset by software. In this case, after connecting diagnostic equipment to the car, a misfire in cylinder 2, misfire in cylinders 2 and 3, etc. can be detected.

The misfire error itself is indicated on the scanner by the letter “P”. For example, p0301 indicates that a misfire in the first cylinder was detected by the ECM and recorded in the ECU memory. Error p0302 (misfire in cylinder 2) will indicate specifically the second cylinder, p0300 - random multiple misfires detected, error 300 misfire, overshoot, etc. In any case, this error indicates that there is a problem that needs to be fixed.

Symptoms of a problem

A mixture misfire is a failure to ignite the fuel-air mixture or its untimely ignition. In any of the cases, the system counts the number of misses and delays, and, if necessary, turns off the idle cylinder or even a pair. On most cars, the first sign of a malfunction is the “check” symbol lighting up on the dashboard.

Also among the common signs can be noted:

Smell of fuel from the exhaust pipe. Since the mixture did not ignite in the cylinder, it is discharged almost unchanged or partially neutralized.
Shoots in the exhaust system. If a partial fire occurs, the catalytic converter is severely damaged, which can lead to popping noises.
Loss of power. The engine does not work properly, causing the crankshaft to spin at a lower speed, resulting in a significant loss of power.
Engine tripping. Failure of one or a pair of cylinders leads to the fact that the engine begins to vibrate during operation and other signs of malfunction appear.

In cars with an electronic control unit, there are several types of errors that indicate a breakdown.

P0300. It is a sign of multiple failures in the process of ignition of the combustible mixture in different cylinders.
P0301 - p0304. The last number shows which cylinder is not working properly.

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When does error code P0300 pop up?

Note that the P0300 error code is recorded by the control unit only when misfires are detected in several cylinders simultaneously, since a misfire in one of them is recorded after two repetitions in a row, and the rotation speed of the CV is important. At idle, the error is stored in memory after 3.5 minutes of engine operation, and at speeds above 2 thousand - a little more than one minute. The threshold for registering a DTC in the ECM memory is more than 3.25% of missed flashes per 1000 revolutions. If misfires are detected only in a certain cylinder, then not error P0300 is generated, but another one, with the serial number of the combustion chamber of the internal combustion engine.

Troubleshooting

The task of diagnostics for misfires is to determine which cylinder on your VAZ 2114 has problems.

Main causes of misfires

First of all, your light comes on, signaling the need to check the engine. During diagnostics, an error lights up - P0300.

The table provides information regarding which error code corresponds to problems in a particular cylinder.

Cylinder number	Error code	Where is the pass
№1	P0301	Problems with the first cylinder
№2	P0302	Problems with the second cylinder
№3	P0303	Problems with the third cylinder
№4	P0304	Problems with the fourth cylinder

How to diagnose and fix omissions

If you read the article from the beginning, you now know what can cause gaps. If you came straight to this point, then we will briefly write down the possible reasons for you. Omissions occur when one of the following is missing or occurs at the wrong time:

Ignition.
Fuel-air mixture.
Compression.

To diagnose omissions, we must check everything. But some mistakes are more common than others. Starting in the right direction can save you a lot of time. Let's write a short guide on what to do when trying to find the cause of a misfire.

Reading errors

The first thing to do is read the errors from the ECU. You can do this yourself. You can use the ELM327 adapter and Torque or ScanMaster software. It's inexpensive and works with most brands of cars.

Diagnostics

The first signal of problems with the engine is the lighting of the Check Engine indicator on the instrument panel. If the car has a standard on-board computer, then you can read the ignition system errors on it. But it is not able to show the operation of the device in real time, so a more accurate way to determine the fault code is a diagnostic tool that is connected to a special connector.

Regardless of the type of equipment to check, there are several main error codes that occur when a VAZ 2114 misfires:

P0300 - a general problem in the system, the presence of numerous misfires on all cylinders;
P0301 - malfunction of the spark plug of the first cylinder (cylinders are counted from the unit drive pulley);
P0302 - problems with the functioning of the second cylinder;
P0303 - problem in the third cylinder;
P0304 - malfunction of the fourth cylinder.

Error 0302

Error 0304

Online consultation

Codes P0300 and P0304 are entered if:

— the engine is running; — the crankshaft speed of the N40 engine is in the range of 720...4600 rpm; — the system performs misfire recognition diagnostics (B_LUSTOP= “No”); — the uneven rotation of the crankshaft measured by the controller exceeds the threshold; — there are no fault codes P0201...P0204, P0261, P0262, P0264, P0265, P0267, P0268, P0270, P0271, P0336. If the system detects misfires that lead to an increase in exhaust gas toxicity, the malfunction indicator lamp lights up after 2 drive cycles. If the system detects a misfire leading to damage to the catalytic converter, the malfunction indicator lamp begins to flash immediately after the fault code is entered into the controller's memory. In order to protect the catalytic converter, the fuel supply may be turned off to those cylinders in which misfires have been recorded. Description of checks: 1. The presence of a permanent fault is checked. 2

It is necessary to use a spark gap (spark tester), as it is important to determine whether there is sufficient secondary voltage at the spark plug (more than 22,000 V). 3

If carbon tracks are present, replace the ignition module and check the condition of the high-voltage wires. Diagnostic information:

If misfires are intermittent, you need to check for the following faults: - unreliable grounding of the controller. Check that the injection system wires are securely connected to the cylinder block. Make sure that the contacts are not contaminated;

- air leak. Check the intake system after the mass air flow sensor for air leaks. Make sure that the vacuum hoses are connected securely and are not damaged; — malfunction of fuel supply system elements. A clogged fuel filter and a malfunction of the electric fuel pump can lead to a lean air-fuel mixture. In addition, it is necessary to check the balance of the injectors; — malfunction of ignition system elements. Check for wetness, cracks, wear, abnormal spark gap width, damage to the electrodes or large deposits on the spark plugs (if the mileage of the spark plugs on the car exceeds 30,000 km, they must be replaced). Check the high-voltage wires and the ignition module housing for damage; — weakening of the DPKV fastening; — strong (more than 0.4 mm) radial runout of the damper rim (drive disk). Misfire may occur briefly when starting a cold engine at a coolant temperature below 10°C due to dirty spark plugs. After the engine warms up, the misfires disappear.

Consequences of error P0300

If a misfire occurs in the engine in the exhaust pipe the level of exhaust gas toxicity increases , which, in turn, can also lead to an increase in the temperature in the catalyst, which causes its damage (the honeycombs melt because the temperature exceeds the threshold of 800 °C ). On some cars, in order to reduce the burnout of fuel in the catalytic converter and, consequently, the level of toxicity, the ECM unit monitors the frequency of misfires using crankshaft and camshaft sensors and, in addition, it registers error p0300, signaling a checkengine light can also , in which the gap was discovered. It is worth mentioning that most often, for some reason, the owners of cars such as Lacetti, Matiz, Priora and other injection VAZs, as well as Opel, Nissan, Kia cars, are interested in the reasons for the occurrence of this error.