What are VAZ 2114 misfires: reasons, video about what causes them and how to fix them

02/04/2022 54 212 VAZ 2114

Author: Ivan Baranov

There are probably no drivers, especially those with extensive driving experience, who are unaware of such a problem as misfire in cylinders 1 and 4 of the VAZ 2114. This is expressed in the fact that the car jerks and cannot move. In a word, a very unpleasant problem.

Previously, all units had 4 cylinders, and if problems arose with one, then the engine, as they said, began to “triple” and function on 3 cylinders.

VAZ car cylinder block

Nowadays, the situation is somewhat different because the units produced today can even have twelve cylinders. Of course, the phrase “troubling the engine” is no longer relevant, but it still remains and is mentioned when the operation of one of the cylinders is disrupted.

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Causes of misfires

If, on average, for every hundred operating cycles in the cylinder there are 3-4% cases of non-ignition of the mixture, then the VAZ 2114 engine management system begins to record misfires. There may be several reasons for this situation to occur and they do not depend on the type of engine - be it 1.5 liters or 1.6 liters.

The reasons why there are interruptions in the operation of the ignition system on the VAZ 2114 engine lie in various defects in the cylinder-piston group units, the gas distribution mechanism and the ignition system.

These problems can occur due to natural wear and tear of components or damage as a result of careless maintenance work:

Incorrect functioning of the rough road sensor, which is installed on the VAZ 2114, meeting Euro 3 standards and higher. Because of this, when driving over uneven roads, there may be erroneous misfire signals, which disappear after driving on a good road.
Poor mixture formation and the appearance of frost on the elements of the ignition system. Misfires may occur when starting the engine in low temperatures. On a working engine, such incidents disappear after a few seconds and are not a signal of a problem.
Burnt out gasket between the head and block. In this case, misfires occur as the speed increases and the load on the power unit increases, i.e. during acceleration. At the same time, in idle mode the engine operates absolutely normally.
Wear of cylinder rings and mirrors. Misfires appear on a cold engine and disappear as the unit warms up.
Old or damaged spark plugs. Over time, the gap between the spark plug electrodes increases or becomes covered with a layer of soot. In this regard, there is not enough voltage in the ignition system for stable breakdown of the air gap and ignition.
Faulty high-voltage wires or contacts on them. Over time, the insulation on the wires deteriorates or can become damaged during various engine maintenance tasks. With such defects, the cables are not able to provide a stable supply of high voltage to the spark plugs. The contacts on the wires themselves may become covered with corrosion products or become oily.
Incorrect operation of the ignition module, which is installed on engines with an injector to supply a spark to the spark plugs.
Using low-quality gasoline, which causes carbon deposits to form on the spark plugs and clog the nozzles on the injection nozzles.
A decrease in compression pressure caused by worn rings on the pistons or loose valve seats. In turn, valve leaks can be caused by the formation of carbon deposits on the mating surfaces and incorrect adjustment of the drive mechanism.
The engine sucks in excess air through leaks in the working mixture supply system.

Compression drop

Carbon deposits on spark plugs

Burnt gasket

The video from the KV Avtoservis channel presents the diagnosis and elimination of the cause of the misfire error.

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.

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

Troubleshooting

The main task and purpose of diagnosis will be to determine which cylinder has problems. In the VAZ-2114, if there are errors in misfire, a special code is provided, which, when checked, displays the necessary values.

So, if there is a problem in the first cylinder, then the code will look like this: P0301 , if with the second, then the last digit in the error will change to “2” - P0302, and so on up to four, indicating all four cylinders respectively.

As you can see, diagnostics can report in detail about problems in any cylinder.

When a bad cylinder was discovered, it remained to understand what was causing these malfunctions.

Main problems

Please note that when carrying out the following work, you must have some experience, since carrying out various operations related to the ignition system in a non-working cylinder can lead to other problems that will only aggravate the existing situation.

Compression in the cylinder block. This indicator should be checked first, because often due to a large difference in readings, misfires occur in the cylinders.

Spark plug . The layer of soot that forms on them, as a rule, reduces the gap on the spark plug, and it can no longer properly perform all its direct functions. Often candles refuse to work simply because they are made from questionable materials, questionable quality and at a questionably low price. The only conclusions that can be drawn from this are the following: do not skimp on spark plugs and check them on time.

Dirty spark plugs

Timing marks on the VAZ-2114 engine pulley

Here we also combine

How to fix the problem?

The way to eliminate problems that arise is to replace damaged or worn parts.

It is better to correct such defects in a specialized service, where they will first clarify the cause of the problem.

Some causes of misfires in the VAZ 2114 can be found and eliminated yourself:

If gaps and error 300 appear on the computer screen, you need to unscrew all the spark plugs, check the gap between the electrodes and see if there is a lot of carbon deposits on their surface. For errors like 0301, 0302, etc., you need to pay special attention to the condition of the spark plug in this cylinder.
It is necessary to visually inspect the wires leading to the spark plugs; if cracks are found on the surface, they should be replaced with new ones.
Check the condition of the camshaft drive belt and the alignment of the marks on it. If the phases are violated, it is necessary to adjust the gas distribution system.
Check the compression, which should not be lower than 10 and not higher than 14 Bar and should not have a spread across the cylinders of more than 1 Bar. If the pressure is low, it is necessary to check the valve clearance adjustment.
Check the clearances in the valve mechanism. Sometimes when adjusting, the clearances are set incorrectly and the exhaust valves do not close completely. Monitoring and adjustment of clearances must be carried out every 20 thousand km, and when using gas as fuel - after 10 thousand km.
If there are misfires in different cylinders that occur under different operating conditions of the unit, the ignition module must be replaced.

What can multiple misfires lead to?

Single misfires are only a signal to the owner of a VAZ 2114 about problems with the engine.

Numerous incidents entail the following consequences:

As a result of misfires, unburnt fuel will enter the catalytic reduction system. Because of this, the converter will overheat and fail.
With repeated misfires, some of the gasoline will enter the lubrication system through the walls of the idle cylinder. Oil diluted with gasoline will lose its properties and will not be able to provide high-quality lubrication of loaded engine elements.
All these factors can lead to engine failure and the need for expensive repairs.

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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