Cylinder 4 misfires. Misfires: Causes and Solutions

And the motor itself began to work with some kind of interruptions, or it was difficult for the car to go uphill and only in second gear - it can be said with certainty that the engine is to blame. However, what exactly is wrong with it and why did the car begin to behave this way? This and much more will be discussed in my article today.

If the display is in the form of the English letter “P”, the reason is most likely a misfire in the cylinder.

So, I give you a list of common misfire errors, as well as their classification:

• P0301 - misfires in the first cylinder;
• P0302 - misfires in the second cylinder;
• P0303 - misfires in the third cylinder, etc.

So what do we have? There is a breakdown that needs to be fixed, here, as they say, everyone decides for himself what suits him best: go to a car service, where the masters will help you solve the misfire problem, and the second option is to find the cause and fix it yourself.

Causes of cylinder misfire

Let me start by saying what is a misfire? This definition is usually called the phenomenon in the motor, when one of the cylinders accelerates a little slower than the others, which actually violates the working process of the engine and the cycle of the cycle. Often, the consequences of a misfire, for example, such as exhaust deterioration, are of little interest to anyone. Most car owners are most often worried that the car practically does not drive, constantly “twitches” and cannot cope with the load.

What is misfiring is more or less clear, now I propose to deal with the causes of this phenomenon. In fact, there are a lot of such reasons, so I will list the most typical ones.

It is not uncommon in reality that when a misfire occurs in the cylinders, each motorist begins to logically try to determine the cause and, first of all, checks the entire electrical network of the car. However, in the end, often the cause lies in the faulty valves of the car.

We are looking for the cause of the misfire in the cylinder

Car owners, cars that are equipped with "electronic brains", are a little more fortunate in this matter, since there is the possibility of using an autotester. Thanks to the “brains” and testers, you can see, for example, where exactly misfires occur in cylinder 1 or 3.

In addition, with the help of a scanner, you can also determine the direction of the search itself. If the scanner showed you code P0204, and you know that this is an injector malfunction. Code P0300 indicates random misfires in all cylinders. Therefore, we can conclude that the air-fuel mixture is deteriorating, which means that the reason may lie in high air leakage from the recirculation valve or in low pressure due to a faulty pump.

If a misfire appeared in a car that does not have an electronic assistant, then you will have to look for the cause using “old-fashioned methods”. They begin with the fact that the electrical equipment under the hood is checked: candles, BB wires, after which the compression in the cylinders and the condition of the fuel pump are measured.

If none of the versions has been confirmed, there are two ways out: either continue an independent search, or go to the service station for help, where they will help you fix the problem for money.

What ECM malfunctions can trigger the misfire diagnostic?

As mentioned above, the recognition of misfires occurs by uneven rotation of the crankshaft. This is an indirect measurement method, it registers the very fact of the presence of increased unevenness, and also determines the faulty cylinder, but does not indicate the cause (that is, the faulty component of the engine management system). The presence of codes P0300 - P0304 in the controller error memory requires a thorough diagnosis of the entire control system, as well as the engine itself. The following are the most common faults that trigger the misfire diagnostic.
ignition module. An open or interturn circuit in one of the coils leads to the fact that high voltage is not applied to one or a pair of cylinders (1-4 or 2-3). The performance of the ignition module is checked using a high-voltage arrester.
Spark plug. Incorrect spark gap, moisture, conductive paths, cracks, carbon deposits on the insulator, leaking spark plugs cause problems with the ignition of the air-fuel mixture. There are special stands for checking candles, but the most effective method of checking is to replace them with new ones.
High voltage wires. The most common malfunctions are wire breaks (resistance should be in the range of 6-15 kOhm, checked with an ohmmeter) or insulation damage.
Nozzles. A stuck open or closed injector will cause the air/fuel mixture to not ignite. In the first case, spark plugs get wet from an excess amount of fuel. To evaluate the performance, it is necessary to balance the injectors. Another option for a malfunction of the injectors is an interturn circuit in the winding.
Throttle position sensor. The cause of the misfire diagnostic may be a throttle position sensor with a worn resistive layer. A sharp change in the characteristics of the sensor with minor movements of the gas pedal leads to a sharp change in engine modes, which will cause increased uneven operation of the engine. The TPS performance can be checked with a scan tool by gently depressing the gas pedal and monitoring the gauge for changes in the sensor signal.
Lean air-fuel mixture. When the air-fuel mixture is depleted (a> 1.20), problems arise with its ignition even with a working ignition system. The overrun can be caused by:

Leakage of the intake system;
- a malfunction in the fuel supply system;
- low fuel level in the tank;
- a malfunction of the mass air flow sensor;
- Malfunction of the oxygen sensor.

Mechanical malfunctions of the engine. Any mechanical failure of the engine that interferes with gas exchange in the combustion chamber or prevents the crankshaft from turning smoothly can trigger a misfire diagnostic. The elimination of such malfunctions is the most time-consuming, as it requires disassembly of the engine. In many cases (but not always) the presence of mechanical problems can be judged by the change in compression from cylinder to cylinder.

Damper with toothed rim. With the magnetic interaction of the crankshaft position sensor with the damper ring gear, a signal is generated from which the controller calculates the current piston position, crankshaft speed, and acceleration. Strong beating of the ring gear, a large angular error in cutting the teeth of the ring (for example, if the damper was made in handicraft conditions), as well as a damaged rubber damping layer can lead to erroneous acceleration calculations and, as a result, to false recognition of misfires.
Coolant. The ingress of coolant into the cylinders will lead to a violation of mixture formation, and hence to non-ignition of the air-fuel mixture.

As can be seen from the above, there can be many reasons for triggering the misfire diagnostics, another thing is that some malfunctions are common, others are extremely rare. Detailed troubleshooting techniques are given in the maintenance manuals for VAZ vehicles, so we will not dwell on them in detail. I just want to focus on one point. If you are faced with the task of finding the causes of the appearance of codes P0300 - P0304, then the first thing you need to check is how the engine is working at the time the codes are registered. In other words, the engine “troits” (for example, during gas changes) or works evenly. This depends on the direction of the search. A “crooked” damper, a lean mixture (very often), wedging of a water pump do not lead to deviations in engine operation that can be determined by ear. On the other hand, the failure of spark plugs, ignition module, high-voltage wires, injectors, low compression in the cylinder significantly affect the operation of the engine.

There are various situations that affect the poor performance of the power unit. One of them is misfiring in the cylinder, when in one or 2 combustion chambers, individually or simultaneously, the fuel mixture ignites poorly, or such a process does not occur at all. Therefore, what are the causes of misfiring, and will be discussed below.

How to determine that the cylinders are not working correctly

The operation of any gasoline power unit depends on many factors and systems. Therefore, when a motorist notices his incorrect operation, or other changes, you must immediately find out the cause, and try to eliminate it on your own and go to the service station.

To spend less money, motorists must find out the cause themselves, and then decide how to localize it. Therefore, if a motorist begins to notice that under load or idling, his engine loses power, random detonations, strong vibrations, black exhaust gases, tripling are detected, and in general the engine does not work well, then one of the problems may be poor ignition of the mixture, its incomplete combustion. The reasons may be different and are discussed in detail below.

At the same time, it must be understood that injection engines differ in the structure of the fuel supply to the combustion chamber from gasoline ones. Therefore, depending on the type of power unit, multiple misfires may differ from each other on carburetor and injection engines.

It is important to remember that the ignition module plays a significant role in determining the causes of poor ignition performance. It will certainly signal to the electronic on-board devices about problems that have arisen in the form of various fault codes that you need to be able to decipher.

Reasons for misfiring

In order to understand this issue, first, motorists must have a clear idea of ​​\u200b\u200bwhat a misfire is.

In the ideal operation of a gasoline engine, even if it is on gas, the fuel mixture, which is enriched with air, should ignite at top dead center - TDC (where the cylinder enters). This is necessary so that the cylinder, moving some more distance, compresses it, and receives the necessary power when moving down.

All engine cylinders work synchronously, that is, when two of them approach TDC, the other two are already at the bottom, giving the necessary power to the engine. If such synchronism is violated, then the power unit loses power.

When a misfire occurs, the fuel mixture ignites poorly, it ignites every other time, or there is no spark at all, which leads to loss of power, strong explosions (detonation) inside the combustion chamber, and even destruction of the cylinders and motor.

To prevent this from happening, you need to carefully listen to the operation of your engine.

Now consider why misfires occur at idle, as well as when the car is moving.

1. Poor fuel quality. If the car is refueled with the wrong fuel, which is put to it by the manufacturer, or it is simply made from low-quality raw materials, then the nozzles begin to clog, soot appears on the spark plugs, and the operation of the fuel pump may also be disrupted, its filter becomes clogged. If the fuel change did not affect the operation of the engine, then you will have to clean the nozzles, filters, and also check the spark plugs.
2. Spark plug . These elements ignite the fuel mixture. If they become unusable, for example, on the second or third cylinder, then the combustible mixture will not be ignited at all, or it will partially ignite, because a weak spark is emitted, losing its strength due to soot, or because the electrodes burned out, or the protective cover collapsed. You can eliminate this cause by completely replacing the candles. To do this, if there are problems with the ignition, you need to know how to check the spark plugs yourself.
3. Faulty high voltage wires. These elements are responsible for ensuring that the spark plugs are supplied with the necessary current in order to produce a strong spark. There are three reasons why one or more cylinders do not work. A breakdown of electricity on the motor block, that is, the integrity of the protective shell is violated, which leads to a decrease in the strength of the spark, especially on a cold engine. The second is a break in the transmission core. In this case, there will be no spark at all, and you can hear that the cylinder does not work at all. The last reason is the high resistance, which will dampen the current, and prevent the spark from gaining the necessary power.
4. Malfunction of the ignition system and its modules. This reason appears more often in injection engines. This is due to the fact that the on-board computer monitors the ignition distribution, and it is distributed among the candles thanks to the electronic distribution. If the module breaks down, or some of its parts fail, misfires begin.
5. Bad compression. If the power unit has passed a significant mileage, then compression on some cylinders may be broken. The reason for this may be different situations, for example, wear of piston rings, cylinder walls, improper valve adjustment. If this happens, it will be difficult for the driver to start his car when it is cold (after some downtime), plus it will not idle well.
6. Broken cylinder block. This is a serious cause, which can be caused by damage to the cylinder, its deformation, or great wear (strong wear appears).

It is important to understand that, having discovered some changes in the operation of the power unit, the motorist does not need to disassemble it all, and start looking for the cause. It is enough, first, to check for a misfire, and if everything is working fine, start thinking about a serious repair.

Misfire detection

Having understood the reasons why they can occur, motorists should understand how to identify them in time and, of course, immediately eliminate them.
It is easier for those who have a car equipped with an on-board computer. He will always give a certain signal that will signal a misfire (poor operation of one or another cylinder). The (CHEK) symbol will light up in red. Further, it will be reported that an error has occurred, and an encoded message is submitted.

Consider the decoding of errors indicating misfires in specific cylinders.

• P0302 - a pass in the second cylinder;
• P0301 - a pass in the first cylinder;
• P0303 - respectively, the delay in the third cylinder;
• P0304 - respectively in the fourth cylinder.

For cars that have power units with a large number of cylinders, respectively, the last digit will indicate its number.

For example, it will look like this: the on-board computer displays the inscription - CHEK and then P 0301 P0304, which means misfires in cylinders 1 and 4. Therefore, having such signals, the driver will already know which pistons to check.

The situation is more difficult with those who have used cars equipped with carburetors. To find out the problem. They will have to carry out some manipulations with the power unit.

Consider them:

• checking power (high-voltage) wires, for this it will be necessary to carry out their visual inspection for damage to the protective shell and sparks, or with a multimeter for resistance, if problems are identified, then they need to be changed;
• checking spark plugs, for this they will need to be unscrewed, checked for carbon deposits, the correct gap between the electrodes, as well as electrode melting, if the candles are in order, and for example, there is a misfire in cylinder 3, then the reason is not in them;
• pressure test, for this you will need to unscrew the candle on one cylinder, then take a pressure gauge to the hose and connect it to the place of the unscrewed candle, when the crankshaft moves, the pressure gauge will show what pressure is, if it corresponds to the technical parameters, then the procedure is repeated with another cylinder, if not, then you need to look for the cause of poor pressure;
• checking the operation of the gas distribution system, it directly affects the distribution of the spark over the candles, therefore, without identifying other reasons, the motorist should pay attention to it, the reasons for such a misfire can be different from the wear of some elements to incorrectly set marks.

This is how you can identify the causes of misfire on various power units.

It is important to remember that car diagnostics, even if it is not equipped with a modern on-board computer, can be carried out using special devices, the sensors of which are connected to the necessary nodes, the engine starts and diagnostics begin. But such equipment is expensive.

There are many reasons why a misfire occurs. They are described above. Each motorist must understand that the quality of the motor, as well as the extension of the motor resource, depends on their timely detection.

• How to check and identify idle cylinders with your own hands?

I can assume that there is plenty of information on the Internet, what are the causes of misfires and stories from the life of cars with this disease.

For many car owners, this is just a shock or even a hysteria with a panic attack when the consumption is like that of a BELAZ, the traction is like that of an overloaded moped and you don’t know what, why and how, but whether it’s fatal or treated on your own.

The logic is sometimes banal, but common cause of multiple misfiring that there is no spark, which means in the ignition system. Of the abnormal reasons, there may be a state of the cylinder-piston group and fuel supply, but these are more reasons for why the engine is troiting or joking.

With multiple and random misfires, the cause is in the ignition module, less often in the engine wiring.

A dead candle or wire gives a consistent and logical misfire in the cylinder that is fed, and not just any and when they want, as is the case with a dying ignition module.

With misfires in all cylinders, the reason is similar, since misfires can be sequential and this can be seen with computer diagnostics.

A good example in the video is how the ignition system works and spark formation occurs.

To identify the causes of multiple misfires?

Candles

The condition of the spark plugs, the commonplace cause of misfiring, and a clear way to find out, unscrewed and looked. If the candle does not burn gasoline or gas, then this is clearly visible immediately after the engine has run. Do not turn on hot, but do not wait for the remaining fuel to evaporate.

High voltage wires

In general, everything is simple, checked for rupture and resistance. Sometimes it is not immediately noticeable, but if the wires have creases or a break in the insulation, then during vibration or wet weather they can make themselves felt.

Wiring

It may seem like a titanic job, but if you know how to use a multimeter, then it is no more difficult than the first two causes of misfires. We take out the wires from the corrugated hose and one by name for integrity. A broken wire can give a gap during vibration when the engine is running.

Ignition coil

The most common cause of failure of the ignition coil is the failure of the spark plug or wires. Let's just say that the voltage in the coil is not released through the wire and the spark into the candles and takes all the blow.

Some engines have structurally positioned the ignition coils so that after washing the engine, it fails due to moisture ingress.

ignition module

The most common cause on domestic cars is due to low-quality ignition modules. The module conditionally consists of two parts, if the gaps are in two paired cylinders, and the wires lead to one side of the module, then the reason indicates itself.

It happens that the ignition module can be half working. In this case, the thrust disappears and is not particularly noticeable in the operation of the engine, since it doubles synchronously.

How to check and identify idle cylinders?

The surest and safest way, as well as the most correct and effective one, is to connect to the computer with a good diagnostic program and an oscilloscope. This is best done by a diagnostician.

The diagnostic program will show which cylinder is not working properly. The exclusion method described below is carried out with the help of software shutdown of the injectors, which is safe for the coil.

Engine operation graphs will show where the failures are in the engine, at idle or under load.

Check idle cylinders with your own hands

We determine idle cylinders using candles

1. We unscrew all the candles.
2. We lay it out in order, as in cylinders.
3. We look and compare the state.

If we see that they are different, as for example in the photo. The second and especially the fourth cylinder are a little darker, which means carbon deposits are created due to misfires in these cylinders.

We determine the performance of the cylinders using high-voltage wires

To identify problematic cylinders, we use the method of excluding working ones, or, better, finds working cylinders.

Be careful and don't touch the body when you do the method described below, electricity, after all.

With the engine running unevenly, one by one (carefully and for a short period) remove the wire from the candle. As soon as the operation of the engine has changed (it starts to stall, the speed drops, it starts to triple more strongly), we install the wire back on the candle, which means that this cylinder is working normally, i.e. it sparks. You can roughly estimate the condition of the injectors.

When the wire is removed from the spark plug, and the engine’s operation has not changed, how it worked and how it works, uneven and troit, or the changes are insignificant - this cylinder is problematic, since there is no spark in it or there are already gaps, a clear absence of a spark and the wire in your hand confirms this.

Do-it-yourself ignition module check

Video: Calling wiring and ignition module

The best way to check the ignition module is to insert the wires into a working one and connect power to it, without installing it on the car. If you find a good seller and agree on such an opportunity, it will be good, but the chance is that the new one is the same as your old one on cheap modules.

It is better to check on the ignition module, which is removed from a properly working engine. You exclude checking with a defective coil, which drives you into a dead end.

One of the most annoying problems in the operation of an internal combustion engine is misfiring. This is the moment when one of all cylinders does not work due to a malfunction in the ignition system. There is an opinion that it is incredibly difficult to determine the causes of this problem, but misfires must be fixed. At the moment of misfiring the fuel, one cylinder fails, which significantly affects the engine power - 25% of the potential of the power unit is lost. The remaining three cylinders (if we are talking about a four-cylinder engine) are forced to work for themselves and for that guy, so fuel consumption increases markedly. In addition, a misfire unit does not start well, trembles at idle and stalls under excessive loads. These are the unpleasant consequences of a misfire.

It is worth noting that the ignition can be skipped both constantly and at certain intervals, or even randomly. If there is a constant misfire, one cylinder simply refuses to work. If there is a chaotic operation of the fuel ignition system, the cylinder may either turn on or skip its turn again. This causes very unpleasant fluctuations in speed, serious jerks when the cylinder is suddenly connected. Also, the engine may stall when the cylinder refuses to work during load. It is necessary to deal with this problem and not let it take its course.

Constant misfire in one cylinder - we study and fix the problem

It is worth considering three options for the causes of a misfire in a constant mode. The first option is the lack of a spark, which can also be caused by a number of factors. The second feature of the problem is poor compression in the cylinder. This usually happens after repair work has been completed or at a time when the engine needs to be overhauled.

You can also consider the third option for the absence of fuel ignition - the low quality of the fuel mixture itself. In this case, it is worth changing the gas station and taking obviously good gasoline or diesel, pouring good fuel into the tank and driving a few kilometers. However, with poor fuel, the engine may not start at all, but a misfire is most often worth diagnosing from such nodes:

• spark plugs - a faulty spark plug is the most common problem of poor fuel ignition;
• punched high-voltage wires can also become a certain cause of such an unpleasant problem in your car;
• problems in the electronic ignition control or in the mechanical system (Hall sensor);
• depressurization of one of the cylinders, a decrease in compression and the absence of fuel ignition for this reason;
• too much cylinder wear due to uneven loads or simply a lot of engine wear;
• ignition modules in each car have their own design and differ in many ways, they are also worth checking;
• it is necessary to adjust the ignition at the service in order to understand for sure that this factor does not cause a problem;
• sometimes the reasons can lie deeper and go into the diagnostic field of an exclusively professional service.

Despite the wide range of possible malfunctions, you can check almost all the popular factors for the failure of the ignition system in your own garage. You do not need to use the services of a professional for this, unless you own an incredibly modern Japanese transport, in which even opening the hood on your own is not so easy.

If the problem was not detected on your own, you will have to contact the service center and pay for professional diagnostics. In this case, you will be able to detect and fix the problem quickly enough, as well as get a guarantee from specialists that this situation will not happen again in the near future. True, the services are also different, and not every company will help you to qualitatively eliminate problems with the car.

Temporary or interval shutdown of ignition on one cylinder

The problem of constant ignition failure is fraught with the fact that one cylinder from the general set in the car does not work. In this case, the engine shakes, it is very noticeable, power is lost and fuel consumption increases. But if the failures in the ignition are not permanent, but temporary, the problem can be perceived a little differently and interpreted at the service as a malfunction of another node.

If, while driving, you feel a periodic sharp decrease in power and an inexplicable increase, most likely we are talking about a temporary shutdown of one of the cylinders. Such a possibility exists for all the reasons listed above, but not with the final failure of any node, but with its initial failure. In this case, the symptoms of trouble with the car will be as follows:

• poor engine start and operation of three cylinders on a cold car, connection of the fourth cylinder on a hot engine;
• temporary shutdown of one cylinder with a characteristic decrease in speed and loss of power;
• very high fuel consumption and deterioration of the engine oil due to the constant ingress of gasoline into it;
• decrease in the reliability of the engine, the unit may stall for no particular reason in any conditions;
• a special manifestation of malfunctions in the cold season or at high loads on the power unit;
• reduced traction and increased engine wear due to the need for constant work under load;
• fluctuating idle speed, serious jerks during smooth movement in urban mode.

As soon as such troubles occur with your car, you need to go to the service station and diagnose the ignition system. A temporary failure of one of the cylinders most often becomes a harbinger of high costs for an engine overhaul. That is why many owners in this case prefer to put the car in order as far as possible and sell the vehicle to another owner.

If you want to rectify the situation and repair your car, be prepared for unforeseen high service costs. However, in the worst case scenario, you can buy an assembled engine for disassembly without spending too much money on this process. In this case, you can upgrade the potential of the power unit of your car and extend the life of the car for a few more years. The operation of the engine during misfires looks something like the following video:

Summing up

Misfiring can be both an innocuous indicator of a failed spark plug, and a serious demonstration of the need for professional intervention in the powertrain system. With the help of professional diagnostics, you can find out the source of the problem and get more information on how to solve this problem. Despite the many difficulties in the process of finding an ignition problem, often this problem can be solved independently without any problems.

But if we are talking about increased wear of the power unit and poor compression in the engine, you will have to spend money on repairs by performing a major restoration of the most expensive unit in your car. It is especially problematic to find and fix an ignition problem in modern German or Japanese cars. These are machines that contain advanced technology and will actually be a difficult object to carry out repair work without special skills and special equipment. Have you ever had to fix ignition problems yourself?

Misfiring indicates that in one or several cylinders at once there is no complete combustion of the air-fuel mixture. Consider the reasons for multiple skips, why a malfunction can only manifest itself on a cold one, as well as decoding error codes: P03001, P03002, P03003, P03004.

Causes of Multiple Misfires

Signs of a misfire: , reduced power, increased fuel consumption. Uneven operation is clearly visible on 3, 4, 5-cylinder engines, but on V-shaped 6 and 8-cylinder ICEs, it is more difficult to notice the shutdown of one of the cylinders.

Error codes

Modern self-diagnosis is able to register gaps and determine which of the cylinders is the cause of the uneven operation of the engine. Therefore, we recommend starting with the diagnosis of current fault codes. When looking for the cause of a breakdown, it is important to understand in which of the engine operating modes an error occurs due to misfiring.

Without ignition, there is no stroke in the cylinder, which affects the speed of rotation of the crankshaft. receives information from the crankshaft position sensor, therefore, by the moment of deceleration, the CV can calculate in which of the cylinders misfires occur.

• P0300 - multiple misfires. This means that it is not just one cylinder that causes arson problems;
• P03001, P03002, P03003, P03004, P0300n ... - misfires in a particular cylinder. Where N is the serial number of the combustion chamber in which the malfunction occurs.

You can determine error codes by connecting to the OBD II connector using a simple diagnostic tool like ELM 327. It is important that the software version allows you to connect to the engine control unit on your car model.

How to identify a cylinder

If the engine is troit, but you do not know which of the cylinders is the cause, with the engine running, remove the high-voltage wires in turn or disconnect the connectors of the ignition modules, fuel injectors. Disabling the working cylinders will be noticeable by the drop in speed. Problems will be in that “pot”, which will not react in any way to turning off the GDP / connector. We have identified an idle cylinder, so we proceed to search for the cause of misfiring.

Diagnostics of the ignition system

We will not be covering diagnostics of the secondary ignition circuit, which requires an oscilloscope and basic signal handling skills. Let's dwell on the basic verification methods that you can do yourself.

Remove the spark plug. Measure the air gap, assess the condition of the electrodes, insulator and the amount of carbon deposits. We described the diagnostic process in more detail in the article "".

If the candle is wet and there is a bright smell of gasoline, it means that fuel is supplied to the cylinder and claims should be put forward to the power system last.

The best way to independently determine the cause of a misfire in a cylinder is to swap the spark plugs first, then the GDP and ignition modules. Before starting after changing elements, erase all error codes. You can determine a non-working "boiler" by reading actual errors or using the method described above.

Screw the candle from the cylinder in which there are problems with ignition into a working "pot". If the problem migrates to a previously serviceable cylinder, then the cause of the misfire is in the spark plug. Do the same with GDP, individual ignition coils.

On vehicles with a DIS system, the device of which assumes one coil per 2 cylinders, a malfunction of the ignition coil will manifest itself as a misfire in 2 "boilers" at once.

Checking high voltage wires

• Measure GDP resistance. If you know, you can independently compare the obtained values ​​\u200b\u200bwith the nominal ones. Infinite resistance indicates a break - such a high-voltage wire should be replaced.

• Breakdown definition. Spray the GDP with water, start the engine. Connect one contact of the control to an unpainted metal part in contact with the body. Run the second contact along each wire. There should be no spark breakdown between serviceable high-voltage wires and the control.

Attention! The contact must be connected exactly to the "mass", and not to the negative terminal of the battery! Otherwise, during a breakdown, there is a risk of an explosion of the battery. The controller should have an incandescent bulb, not an LED.

Possible malfunctions

At the beginning of the article, the main causes were described, but there are some more rare malfunctions.

• Deterioration of the contact of the resistive throttle position sensor. The ECU cannot adequately calculate the amount of air and the desired load.
• Stretched timing chain, due to which the valve timing shifts.
• Breakage of the damper crown DPKV. Wear leads to uneven rotation of the crown, which can be regarded by the ECU as problems with the combustion of the working mixture.

Don't get caught

On some vehicles, the ECU, after registering a misfire in the cylinder, forcibly cuts off the fuel supply and spark. This is how the catalytic converter protection system works, which prevents unburned gasoline from reaching the catalyst cells.

To prevent this feature from leading you astray when looking for the cause of misfiring, pay attention to the first seconds of cranking the starter/engine. You need at least a few turns of the crown so that the ECU can register the passes. Therefore, in the first moments, the catalyst protection system is guaranteed not to work.