How to check spark plugs, check spark on spark plugs

When should you check spark plugs?

There are several situations in which the driver should think about the condition of this engine component. The machine must be placed in the hands of qualified technicians in the following situations:

When the manufacturer's recommended service life expires. Experienced craftsmen can check whether there is a spark on the spark plugs and test it in a working situation;
Difficulty starting the car - the car starts with great difficulty, and in the cold season it may not start at all;
Unstable operation at idle - the engine stalls when idle at traffic lights.

If necessary, you can carry out all the necessary procedures yourself; for this you just need to know how to check the spark plugs.

How to check spark strength on the ignition module

Most car owners understand that when the engine starts to stall or has trouble starting, the problem is often a lack of spark. Therefore, checking the spark on the injector is a manipulation that should not cause any difficulty for the driver, who often has to deal with the need for repairs in the field. Naturally, you should always have a set of several new, or simply working, candles with you.

Since the lack of a spark is the most common cause of the engine stalling or difficult to start, as well as unstable idling, checking the spark on the spark plugs is carried out by motorists first. In order not to turn out all the spark plugs at once, you can check them one by one - removing one by one from the cylinder head, putting caps on them with a wire from the coil and grounding each spark plug to ground. Rotating the starter should produce a nice, bright spark. If it is missing, you can replace the wire (it is advisable to carry a spare one with you) or use one that is known to be working.

When removing high-voltage wires from the module, it makes sense to number them first - this will avoid confusion in the future. Problems caused by the spark plug or wires become obvious in this way. If a spark does not appear on the spark plug, the problem lies in the module itself. In order to accurately determine this, the “replacement” method will help - the working module can be temporarily “borrowed” from another car of the same model. If replacement fixes the problem, you can safely go to the auto store for a new one.

How to check spark plugs yourself

You can check the presence of a spark and, in general, operability, in several ways:

Start the engine and pull out the high-voltage wires from the spark plugs one by one. If the spark plug does not work, the sound and vibration of the internal combustion engine will not change. And, if you disconnect the wire from a working spark plug, you will immediately feel changes in the operation of the motor.
Turn off the engine. Unscrew the spark plug, place the thread on the body, for example, on the valve cover, and a second person turns the ignition key. It is better for the person holding the candle to hold it with rubber gloves or let it go altogether. His task is to see if there is a spark, and what kind of spark it is.
A special device for checking spark plugs is a pistol. A spark plug is inserted into the gun and it is determined whether there is a spark or not.
A homemade device for testing candles - a piezo lighter with a wire. Connect the wire from the piezo lighter module to the removed candle and place the piezo lighter block itself on ground, then press the button on the block.
There is also a pressure test method. But why use all sorts of complicated methods when the first two methods of checking spark plugs are the most effective.

How to check the spark

From time to time you have to check the performance of the spark plugs to find out some of the reasons for unstable operation. There are 3 ways to check spark plug sparks:

We check for weight.
We check with an electronic measuring instrument (multimeter).
Manual mechanical military method of checking spark. The essence of the method is to make a gap of 4 mm. If the spark hits exactly in the middle, then this is a perfectly working spark plug. If with such a gap the spark hits the side, then this is a poorly functioning spark plug.

Signs that you need to check the spark plugs for a spark:

interruptions at idle speed;
engine tripping;
twitching while moving;
fuel consumption has increased.

Why there is no spark, reasons:

the candles were flooded;
broken high-voltage wires;
contact is broken;
The crankshaft sensor has failed;
the ignition module has failed;
the ignition coil (bobbin) has failed;
the switch has failed;
faulty distributor;
the service life has expired (usually the service life is up to 50 thousand km);
large layers of soot on the electrodes of the spark plugs (due to low-quality fuel and over-suction);
presence of oil on the electrodes (excess oil and worn rings);
varnish and slag deposits on the electrodes (due to various additives in oils and fuels);
melted candles;
mechanical damage to the composite spark plug;
ground contact is poor;
The electronic control unit (ECU) is not working correctly.

Checking the ignition coil for spark

To diagnose the performance of the coil, remove the wire from the distributor-breaker. Next, the test is carried out similarly to testing high-voltage wires, that is, the wire is brought to a metal surface and turned with a starter. The presence of a spark will indicate in this case a problem with the ignition distributor; if there is no spark, then the problem lies in the coil.

First you need to check the distributor contacts. These contacts may oxidize, insulation damage is also possible, and the rotor itself may be faulty. Detecting problems with the rotor allows you to eliminate the problem by replacing it. When checking the ignition coil, you should identify possible defects in the integrity of the winding, burnouts and other signs that a short circuit is occurring inside. If such signs are found, the coil should be replaced or the ignition coil should be repaired.

Now let's take a closer look at ways to check the main elements of the ignition system. To do this, let's go back to the coil. As already mentioned, the most common cause of a malfunction is a damaged winding. Then an insulation breakdown occurs and a short circuit occurs. It is also important to understand that the coil can fail due to overload. Such increased loads occur as a result of problematic spark plugs or spark plug wires. For diagnosis you should:

put the car in a dry parking, repair or other box. You can also use the garage. The main thing is that the humidity is not too high;
Next, you will need to clean the distributor cover from dirt, after which the specified cover must be removed;
then you need to turn the engine crankshaft so that the distributor contacts are closed;
Now you can turn on the ignition and bring the high-voltage wire of the distributor 3-7 mm to ground;

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After evaluating the spark, you can decide whether the ignition coil needs to be replaced. Please note that repairing this element is often impractical. Also, when installing a new spare part, you should strictly adhere to the required polarity. If this is not done, then the new part will quickly become unusable after unqualified installation. Please note that car service centers use a special stand to check coils. Such equipment allows you to check the coil taking into account various operating modes.

To check the spark on the spark plugs if the distributor is working properly and there are no problems with the condition of the high-voltage wires, you need to unscrew the spark plugs from the engine. In addition to the contacts, you should look at carbon deposits, the degree of oiling of the electrodes, etc. For normal sparking, contamination must be cleaned. You should also check the gap between the electrodes, which is usually between 0.7 and 0.9 mm. If the gap is broken, then you can carefully bend the side electrode. This method is a temporary measure, but in some cases it allows you to drive from several tens to hundreds of kilometers without tripping the engine in case of problems with the spark plugs.

We also add that there are special pistol devices for checking spark plugs. Typically, such solutions are available from spark plug sellers in car dealerships or automotive markets. If there is such a possibility, then the spark plugs can be checked on similar equipment.

Ignition coil and its structure

The mechanical operation of gasoline engines occurs as a result of the combustion of a fuel-air working mixture in the cylinders, which is ignited by an electric spark. The ignition circuits are powered by the car's on-board power supply, which for safety reasons has a 12-volt voltage, which is not enough to create a spark. The simplest way to produce high voltage is to use a step-up transformer, which is traditionally called a coil.

The transformer does not work with direct current. At the same time, a short spark is enough to ignite the mixture. To obtain it, a breaker is introduced into the ignition circuits. The current jump at the moment of operation makes it possible to carry out a transformation and remove a voltage of several kilovolts from the output of the coil, which is then supplied to the spark plugs.

The coil contains two windings: low voltage or primary and high voltage or secondary. Due to the large currents flowing in the primary winding, it is wound with a wire with a large cross-section and has a low ohmic resistance. The secondary winding transmits a small current, which allows it to be wound with a thin wire. In addition, due to the need to obtain a high transformation ratio, it contains several thousand turns. Thus, it has high resistance.

Checking the spark on the injection engine

Among the common malfunctions of an injection engine or carburetor engine is when the spark is lost on the spark plugs. In this case, the engine may not start or after starting it may function intermittently (triple), since there is no spark at one of the spark plugs and the cylinder actually does not work.

In such a situation, diagnosis should begin with checking the ignition system. In parallel with this, it is worth taking into account certain features and nuances depending on the type of engine installed. Next, we will talk about available ways to check the ignition for spark in relation to engines with a carburetor, and also consider what to do if the spark on an injection engine is lost.

Read in this article

No spark - possible reasons

The main reasons that there is no ignition spark can be divided into the following groups:

general violation of engine synchronization: malfunction of electrical equipment, blown fuses, main relay, malfunction of crankshaft and camshaft sensors, broken timing belt (or chain);
failure of the spark distribution mechanism (distributor), slider, burnout of the limiting resistor in the slider, failure of high-voltage wires;
spark plug wear;
malfunction of the ignition coil(s);
failure of the engine control unit.

If the spark is lost, when analyzing a complex malfunction, it is necessary to consistently monitor all possible causes in order to accurately determine the main source.

Diagnosis

How to check the spark plugs on the injector yourself? This technique is considered one of the most common and used types of checks. In everyday life, diagnostics proceeds in the following stages:

The elements are properly cleaned: carbon deposits and other contaminants are removed.
Using a probe (a device for controlling the gap), the distance between the electrodes is adjusted.
The wire is strung.
The candle is applied to the metal side of the automobile power unit. This creates the required electrical interaction.

If you have difficulty checking using this principle, then how can you check the operation of the spark plugs on the injector? You can simply start the starter, and then the engine itself. When a blue spark immediately forms upon startup, it means everything is fine. If you get a spark with a red tint, or not at all, a replacement is needed. The spark plug spark test is now complete.

Multimeter device

Tip 1: How to check the spark

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First you need to determine the reason for the refusal. Typically, to start an engine you need fuel, air, and a spark that will ignite the air-fuel mixture in the engine cylinders. If the air filter is ok and the fuel/air mixture is entering the intake manifold, it's time to check the ignition system. You can and should check the spark yourself, without putting this process on the back burner, or rather, before a visit to the service station.

The check is as follows: using a spark plug wrench, you need to unscrew the spark plugs from the cylinder head and carefully inspect them. The first thing you need to pay attention to is the gap between the central and side electrodes of the spark plug. It should correspond to values from 0.7 to 0.9 mm. If the gap is larger, it is necessary to bend the side electrode; if it is smaller, bend it. We also pay attention to the condition of the spark plugs: carbon deposits can also tell us about the operating mode of the engine. To check the spark, carbon deposits must be removed using fine sandpaper.

To carry out the test yourself, you can tie all the spark plugs with wire in a row and ground the free end of the wire to the “ground” of the car, put the tips of high-voltage wires on the spark plugs. After this, using the starter, we begin to crank the engine and observe the formation of a spark between the electrodes of the spark plug. Its appearance and color can also tell a lot. If the spark is weak on all spark plugs or absent altogether, then most likely the electronic switch has failed. If there is a spark, but it is different on all or on individual spark plugs, the problem may be the following:

Checking the spark

If the engine suddenly begins to misfire, that is, to run unevenly and twitch, and other signs of problems with the spark appear (power is lost, the color of the exhaust changes), then you need to check if there is a spark. The first step is to unscrew the spark plug and visually inspect it; a light gray or brownish coating indicates normal operation of this cylinder. If there is carbon deposits on the spark plug, it means there are problems with ignition - the spark plug will have to be replaced.

You can check whether there is a spark in the cylinder without unscrewing the spark plugs. To do this, it is necessary to pull off the caps of the high-voltage wires from the spark plugs one by one while the engine is running. By pulling off the cap, we turn off this cylinder from operation, the engine should start. If nothing happens, then we have found a problem cylinder in which there is no spark.

You can check the spark the old fashioned way. You need to unscrew the spark plug, put the cap from the high-voltage wire on it and bring it to the engine housing. In this case, the assistant must start the car. If a spark appears between the spark plug contact and the motor, then it is working properly.

With any method of ignition diagnostics, you need to be extremely careful not to receive an electric shock from high-voltage wires.

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We unscrew the spark plug, put a high-voltage wire on it and install its base to ground (for example, the engine). We check for the presence of a spark when the starter is cranked.

It’s even better if you supplement this method with the following technique: close the gap between the electrode with a dielectric (for example, plastic). If the ignition system is working properly, the spark will jump between the central electrode and the skirt. If it is not there, then there is a crack in the spark plug insulator.

Attention! While the starter is operating, do not touch the spark plugs and tips of high-voltage wires.

Method No. 2: Spark piezoelectric probe (for example, Test-M) or lighter.

If you don’t have a ready-made device at hand, you can use an element from a piezo lighter instead. The principle of testing is similar: we connect the device to the upper contact of the spark plug and to the body. The button is pressed, if a spark jumps, then the spark plug is working; if it drips or is missing, then it is broken. Details in the video:

Method number 3: Use a multimeter. You should check the electrical circuit of the central electrode by setting the device to 20 kOhm.

If there is “contact” between the central electrode and the tip (shows resistance), then the reason for the lack of a spark may be damage to the insulator. Video example:

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Each type of candle must have its own resistance. This verification method is less accurate.

These methods work, but they cannot determine the serviceability of the spark plug 100%. For example, a spark plug installed in an engine has a bad spark, but when checked it will look like it is fully working. Why? In open air, the voltage required to form a spark is much less than in a cylinder. In the combustion chamber of an engine, a spark appears in the presence of a compressed air-combustible mixture.

If there is no spark: ignition module

The following symptoms indicate possible problems with the operation of the ignition module:

at idle speed the engine troits;
power decreases, the car accelerates poorly;

Engine vibration is most pronounced in two nearby cylinders, and the drop in thrust is more strongly felt during attempts to sharply accelerate the vehicle, that is, when the accelerator is pressed hard and sharply. In such a situation, the “check” light usually lights up on the dashboard of most cars.

If checking the spark plugs and high-voltage wires does not reveal any problems, then the ignition module should be checked with a tester. The test consists of connecting one output of the tester to the module connector, and powering the other to ground. Then the engine can be started. A tester reading of 12 V is evidence that the module is OK. A deviation in the instrument readings from the norm may indicate either the need to replace the module itself or to check/replace the corresponding fuses.

Why is there no spark at the spark plugs?

There can be several reasons for the lack of spark at the spark plugs. Most often the culprits of the malfunction are:

Accumulator battery;
High voltage wires;
Ignition coil;
Distributor;
Malfunctions in the low voltage circuit.

Also, in the absence of a spark, special attention should be paid to checking the quality of contacts and electrical connections of the ignition system elements. You can check the condition of the contacts by simply rubbing them with your hand. Carefully inspect the wires and blocks of the ignition system - if you find dirt, oil or water on them, they must be wiped with a dry cloth. After that, try starting the engine, it may start this time.

Checking the battery

A clear sign of problems with the battery is a dull and quiet horn signal. Also, if there are problems with the battery, the indicator lights on the instrument panel usually go out while the starter is rotating. In this case, the reason for the lack of a spark may be poor contact at the terminals or a low battery charge.

If the terminals are oxidized, they must be cleaned and tightened tightly. In addition, you can use graphite lubricant, which will reliably protect the contacts from oxidation in the future.
If the battery is discharged, it must be charged using a charger.

Checking high voltage wires

Next, it’s worth inspecting the high-voltage wires: they must have a neat, not “tattered” appearance, without insulation damage, otherwise they will have to be replaced. If the wires are ok, then you can start looking for a spark.

We recommend starting your search for a spark with the spark plug wires. To do this, you need to remove the tip of the spark plug wire from the spark plug and bring it to the “ground” (the nearest unpainted metal part of the body or engine) at a distance of 5-8 mm, after which you need to turn on the starter for a few seconds.

The rotation of the starter should be accompanied by an uninterrupted bright spark of white color with a slight blue tint. If there is no spark, you need to check the ignition coil. A violet, red or yellow spark indicates a malfunction in the ignition system.

It is also worth noting that the spark plugs themselves rarely fail all at the same time. If there is a “spark” in the spark plug wires, you can check any spark plug by unscrewing it from the cylinder head and putting the spark plug wire on it. Touch the metal part of the spark plug to the “ground” of the car, and by rotating the starter, make sure that there is a spark at the spark plug electrodes.

It is necessary to change spark plugs within the time limits established by the maintenance regulations for your car (usually every 15-25 thousand km).

Checking the ignition coil

To check the ignition coil, you need to pull out the central wire coming from the coil from the distributor-breaker cover.

While turning the starter, make sure there is a spark from the wire, similar to the spark plug wires.

The appearance of a spark indicates the serviceability of the ignition coil. In this case, the fault should be sought in the distribution switch.
If there is no spark from the wire, then the cause of the malfunction is hidden either in the ignition coil or in the low voltage circuit.

If there is a malfunction in the ignition coil, it should be replaced with a new one.

Checking the ignition distributor

If you suspect a malfunction of the breaker-distributor, you must carefully inspect its cover from the inside.

If the cap is in order, then simply wash it with gasoline,
If any cracks are found, the cover will need to be replaced.

The center carbon contact of the breaker is checked for sticking by lightly moving it with your finger.

The rotor insulation of the breaker-distributor is checked for breakdown as follows:

Place the central high-voltage wire with a gap of 5-8 mm from the rotor electrode,
After this, close and open the breaker contacts with your hand (the ignition must be turned on).

The appearance of sparks in the gap indicates a rotor malfunction that will need to be replaced.

Low Voltage Circuit Test

To check the low voltage circuit, you can use a 12 V test lamp with a power of up to 3 W. The lamp is connected on one side to the low voltage terminal of the breaker, and on the other to the vehicle ground.

After this, you need to manually close the contacts of the distributor-breaker and turn on the ignition. If the low voltage circuit is working properly, the control lamp should light up when the contacts open, and go out when they close.

If the lamp does not light up when the contacts are opened, it means that the fault is hidden either in the low voltage wires or in the primary winding of the ignition coil.

Constant lighting of the lamp, in any position of the contacts, indicates one of three causes of the malfunction:

Severe oxidation of breaker contacts;
Broken wiring leading from the breaker terminal to the lever;
Broken wiring connecting the movable disk of the breaker to the housing.

If the cause of the malfunction turns out to be oxidized contacts, then they must be cleaned, after which the gap should be adjusted.

Replacing spark plugs

There are spark plugs (SZ) and glow plugs (CH). The former are used for gasoline engines, the latter for diesel engines.

Symptoms of SZ problems:

The internal combustion engine does not start well;
the engine “troubles” (accelerates poorly, lacks traction and “power”);
fuel consumption has increased;
the share of carbon dioxide in the exhaust has increased;
engine dynamics are reduced.

For SN the list is as follows:

it is difficult to start the car in cold weather;
at idle the internal combustion engine operates unevenly;
white smoke from the exhaust pipe;
spiral indicator failure.

Important: detection of the listed signs is indirect evidence of the need to replace the spark plugs and requires mandatory inspection.

You can replace the elements yourself or entrust it to experienced car service employees.

Cleaning candles yourself

In many cases, diagnosing a spark plug comes down to cleaning it. After all, a candle covered with soot and dirt begins to work worse and worse.

Self-cleaning takes place using the following methods:

Manual method . No auxiliary devices are required here. It is extremely important to be careful, otherwise the electrode may be damaged. Also, sharp objects are not needed in this case. Will do: a metal brush, a toothbrush, fine-grained sandpaper.
Application of sand . You need a container with it and a drill. A candle is placed in the last one. Its end with the electrode is placed in sand. Let's start the drill. We look at the quality of turnover (insignificant).
Using a sandblasting machine . This method effectively removes deposits and carbon deposits. Different types of sand are used here. The operation takes place with the effect of compressed air.
Chemical cleaning . This method helps to quickly eliminate deposits. Here, agents such as acetone, the drug (Fairy or its analogues) and vinegar are used. A composition for cleaning the carburetor or a rust remover is also suitable. Some craftsmen use Coca-Cola for cleaning. Any of these products is applied in a layer of approximately 3 mm. This lasts for about 4 minutes. Then rinse with drinking liquid. Matches or wooden sticks are used to clean the outer part.
Application of silite . Candles are placed in a jar. This product is poured into it. After which the container is placed under hot water. This results in a chemical reaction. There is an hour wait. You can then clean the electrode with a standard toothbrush.
Using vinegar . The candle is placed in a jar with it. Stay time – 1 hour. Then a little electrolyte is added to this composition. Next, the candle is cleaned. You can use a toothpick.

Do not diagnose spark plugs by removing the caps with the engine running. Risk of electric shock. You can also burn the coil or commutator.

Symptoms of a problem

It is almost impossible to visually determine that there are problems with the current supply in the car. To diagnose, you should start the engine or drive the equipment at high speeds.

Before checking the ignition module, you should clearly know the symptoms of the “disease”. So, the first signals about problems with spark plugs:

The vehicle's crankshaft rotates at the required speed, but the engine does not start. Due to the lack of a spark, there is no ignition of the combustible mixture;
alternate flashes and fires occur in one or more cylinders, and as a result the engine operates unstable and chaotically;
The power unit operates when the car starter rotates. When the “trigger” stops rotating, the unit stalls;
a sharp loss of the machine’s power potential and, as a consequence, increased fuel consumption;
failure of the catalyst due to a large amount of unburned fuel inside the segment;
a long process of starting the engine during periods of medium and low outside temperatures. At this time, a large amount of moisture collects on the outer walls, which does not allow the spark of the candle to pass through;
all kinds of mechanical damage to the spark plug body, which leads to an unstable supply of current to the combustion chamber for ignition.

If there are pronounced black carbon deposits on the spark plug housing, this indicates a malfunction in the power and fuel supply system. Problems with ignition timing can also be caused by worn-out power system wires .

Diagnostic methods

In many vehicles, access to the ignition system components is free and not cluttered with third-party parts. Therefore, the driver can easily check the spark plugs at the initial stage to ensure they are working properly. The main thing is to maintain consistency and not to confuse them when unscrewing them from the cylinders. Checking the ignition module is always carried out with obligatory observance of the order in relation to the group of cylinders. Mixing will lead to incorrect final conclusions.

Initially, you should turn off the power unit, one by one disconnect the wires from the conductors themselves and the distributor. If the sound does not change when starting the engine, then there is a problem. Otherwise, continue your search further.

Spark test

An ignition tester is the easiest and most affordable way to quickly check the ignition system for functionality. We unscrew each spark plug one by one and, if necessary, wipe or clean it of carbon deposits. Using a special tester probe, we check the gaps between the electrode and the conductor body.

Advice. Each car has its own standard of clearances, which can be found in the operating instructions. If you don’t have such a book, seek advice from a mechanic at your nearest service center or look for information on the Internet.

Next, we apply the conductor to the engine body, most often this is the cylinder head cover. In this way we ensure constant contact in the power supply network. We run the starter for 3 - 5 seconds, look for the presence or absence of a spark. We also remember the color with which it skips, as this is important for further diagnostics. Blue color indicates that the conductor is fully operational, red or another color indicates the presence of a breakdown.

There is no spark on an injection engine or an engine with a carburetor, how to check

Checking the spark is possible using several methods: to ground, using a multimeter, or a special tester on a piezoelectric element. The first method is the simplest. The body of the unscrewed spark plug is brought to the metal (usually the engine cylinder block), after which the engine is cranked by the starter and the presence of a spark is analyzed.

Please note that this verification method cannot be used when diagnosing injection cars. The fact is that a car with an injector has an ECU and other electrical equipment that is quite sensitive and can be damaged

The second method allows you to better assess the condition of the spark plug, identify breakdown, etc. The use of a special tester is a method of checking the spark on injector cars, reminiscent in its principle of checking by analyzing the spark breakdown to ground (the first method). In this case, the risk of burning the control unit is minimized. Now let's talk about how to check the spark on a fuel-injected engine.

A complete lack of sparking indicates possible problems with the controller, ignition module, coil or center wire. Diagnostics should begin by checking the fuses. Then you should evaluate the condition of the ground contact, and also check the high-voltage wires.

If there is no spark at the ignition coil, then the functionality of the high voltage wire should be checked. The specified wire must be checked for insulation integrity, have no breakdowns, burnt areas, etc. Detection of any defects is grounds for its replacement.

Also, in the process of diagnosing the ignition system, you should inspect the spark plugs. This must be done if electricity reaches the candles. On carburetor cars, it is enough to remove the spark plug wire, and then bring it closer to a metal surface (for example, a car body) by half a centimeter. Then you need to turn the starter and make sure that there is a spark running between the wire and the metal surface. The spark itself should also have a certain intensity, be white with a slight bluish tint. If no deviations are noticed, then the spark plugs are working. The reason that there is no spark at the spark plug may be the ignition coil.

If you notice problems with the spark plugs, then you need to pay attention to the spark plug contacts. These contacts must be free of contamination

Let us add that if deviations from the norm are noticed, it is optimal to immediately replace the spark plugs. Failure to do so will indicate the need to clean the contacts.

Checking with a multimeter

A universal tester or multimeter helps to quickly check the performance of spark plugs. This device is familiar to many car owners who have had to repair their vehicle. The main purpose of using a multimeter is to detect the presence or absence of a short circuit inside the spark plug.

The multimeter is very easy to use; no special experience or skills are required to use it. For diagnostics, unscrew the conductor, connect one terminal to the spark plug thread, and the second to the central output. When voltage is applied, a spark should appear, which will indicate that the part is working, otherwise it must be replaced. Checking spark plugs with a multimeter is the most common diagnostic option at home. If in testing mode the multimeter shows infinite or very high resistance, then the spark plug is considered non-working.

To check the resistance of the spark plug's built-in resistor, set the multimeter switch to 20 kOhm. One probe of the multimeter touches the central electrode, the other touches the contact terminal. The resistance of all candles should be approximately the same with a slight spread. For spark plugs of injection engines, the resistor resistance is about 4 kOhm.

Pistol check

In addition to checking with a multimeter and a special tester, there is also an original method called “gun test”. Its essence is to examine performance under pressure on a special stand. The algorithm is as follows: insert the conductor into the groove, put on the tip, and after fixing, press the trigger of the gun. A green indicator will indicate 100% performance, a yellow indicator will indicate insufficient conductivity, and a red indicator will indicate a faulty spark plug. Despite the invention of such a device, it does not provide 100% confidence in diagnosis, since the pressure in the gun is somewhat different from the pressure inside the cylinder.

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Cleaning spark plugs

Many novice car owners are faced with the problem of cleaning spark plugs. Careless handling may damage the product or render it inoperable. When cleaning spark plugs with your own hands, use the following generally accepted methods:

manual: a metal brush, rags, toothbrush will be useful. Using light movements around the base, we remove carbon deposits, bringing the product to its standard form. If necessary, use a solvent to remove carbon deposits;
river sand, which can be taken from any beach or pond. Apply a small amount of sand to a rag and gently wipe the base until completely free of waste products;
The sandblasting machine is used in service centers and repair shops. There, sand is supplied under high pressure, along with compressed air;
acetone or other rye cleaner. You can purchase it at any auto store or car market;
Some people use regular Coca-Cola, but its effectiveness has not been conclusively confirmed.

As you can see, checking spark plugs requires very little time, effort and money. Just 10 minutes is enough, and your car will be in full combat readiness. Follow the recommendations of the article, check the color of the spark, then everything will be fine.