Monday, June 28, 2010

Engine characteristics

Engine is a mechanical type. The change of heat energy used to power the drive. , Called the heat engine. This is with several types

The heat engine is a 2.
1, internal combustion engines.
2, the combustion of automotive exterior.
2-engine and can be separated by the table below:

Engines used in cars. Must be small and lightweight. Because of the need to install a limited The capacity to produce a motorcycle and drive around to the other high-use And less noisy. With this engine gas engine petrol or diesel and Rock Lee. An internal combustion engine is the engine currently used in most cars.
Gas engine gasoline engine or Rock Lee.

1st shirt smoking (CYLINDER BLOCK).

Structure made of metal or alloy. Usually have the edge on the edge of the outer wall it helps to increase strength and cooling. Shirt pump includes a cylinder, piston set multiple mobile. And down inside. Top of the cylinder seal was a pump lid. Hermetical, with a pump lid gasket between Smoking and smoking rooms Shirt Cap crankshaft is the lower part of the shirt around the pump cylinder is found by evening.
Cold water and will be found through the channels with the internal lubricant pump shirt also includes a cylinder, piston move up. Mix fuel with air will not leak. And resistance of friction. Between the cylinder piston. Must be low as possible. Therefore, cylinders must be produced efficiently.

2, pump lid (CYLINDER HEAD).

Scum pump is installed above the pump shirt. The hidden room is burning. Cylinder wall and the tongue and swallow. Must be able to tolerate temperatures. And most are to come. From the operation of this engine with pump lid. Is made from cast iron or alloy Aluminum & ???? Pluto The evening performance is better than cast iron sculpture. Cap also includes pump. Cast cold water. Which articulate with cast cold water on the shirt smoking It also cast a cold pump lid. Also cast cold spark plugs.

3-cylinder (PISTON).
– Structure
Mobile piston up and down within cylinder To the duty charged on tempo ID. Compress the explosive mix. And spit out the most important functions of the exhaust cylinder is receiving pressure from the ignition, and this is sent to the crankshaft through the pump shaft. Cylinder was high-temperature heating and always do the most and Must be durable to run around the high over long periods of time. Typically made from cylindrical.
Aluminum alloy. This lightweight and efficient cooling better than other types of materials the name of spare parts. The piston is shown in the illustration below.

– Length of cylinder gap. (Distance between the piston cylinders).
When the piston is heated humid. It will expand slightly. The diameter is increased with this expansion in every period there is a gap between the cylinder piston in place at room temperature (25 g ?, 77, ?) now called the gap length cylinder This gap cylindrical phase shift depending on the type of engine. Period but will usually start from 0.02 to 0.12 mm (0.0008 to 0.0047 inch) cylinder is similar to a slender, small portfolio. Twist, center stage is a split cylinder head is smaller than the bottom of the cylinder slightly. Therefore phase space The piston is the most wide cylinder head. And most narrow at the bottom of the cylinder.

Phase spaces of the piston is measured different This depends on the type of engine repair manual view point to find a measure of gap cylindrical phase.

Period gap is very important plunger. Engine to run correctly and performance is better. If the gap distance is less. Gives no phase gap between the cylinder when the cylinder piston will cause the heating cylinder adjacent to the cylinder. The result can cause the engine to deteriorate. If the gap distance too. In contrast is the pressure caused by the ignition And pressure of gas
The burn is OK. Cause reduced engine performance.

– Piston ring (PISTON RING).
Ring customers will be the bow of the piston ring groove. Outside diameter size of the piston ring is slightly larger than the piston own when combined with the piston in the extended properties of the contractile ring, and it grew to a close attachment to the cylinder wall. Cylindrical metal ring to a high resistance to wear a special kind cast iron plate Projec Emie Pluto That will not scrape the piston ring is a trace amount of cylinder piston ring to vary by type of engine. The number is usually three to four balls, one ring per cylinder.

Piston ring has three major functions is The act prevents air leakage from the fuel and the gap between the piston cylinder. Rooms with crankshaft Rhythm during the implosion and explosion are two functions that prevent the lubricating oil on the side of the piston cylinder. Not to leak out into the room survived burn. The last page is Heat transfer from piston to cylinder wall. To piston cooling.

1) ring compression
This ring prevents leakage of compressed air and fuel mix and the gas generated by burning room packed between strokes. Point and not to explode into the room number of the crankshaft ring is compressed depends on the type of engine. Generally a child will have a piston ring which pumped two “ring on the recorder” and “ring-packed second” ring is compressed, the portfolio characteristics. Therefore, the lower edge of it touched the cylinder wall.
Design such as this to occur as close to the touch. Between ring and cylinder. It is also a sweep oil from the cylinder walls effectively.

Piston ring is the number “1″ or “2″ on it the number “1″ means that Ring and on the number “2″ is the second ring assembly, so this number must face up to the top

2) sweep the oil ring.
Oil ring sweep sweep Cause a film of oil needed to lubricate the surface between piston And cylinder wall. And sweep the excess oil. To prevent the oil drop to ring in the room burn oil sometimes called a sweep for the third ring are two types together. Oil-ring sweep includes the three-piece This three-piece is used.

(2.1) Total
Oil-ring sweep includes the known oil provide feedback. That size is around. And oil is known to be in accordance with this sweeping oil ring groove section that is sweeping over the ring by the fluid into the scourge known these And flow back into the interior of the cylinder.

(2.2), three-piece
Three-piece oil ring sweep includes. Sweeping side plates. To sweep out the excess oil, and the pressure plate to sweep close to the side.
Ring ring groove and cylinder oil sweep a three-piece. To act as a total

(2.3) spaces mouth ring
Piston ring to grow in the same manner as when the hot cylinder With this piston ring has a cut mouth. And when combined within the cylinder will be the appropriate spaces, called gap mouth ring Phase spaces will vary depending on the type of machine. But typically in the range of 0.2 to 0.5 mm (0.008 to 0.020 inch) at normal temperature.

If the gap distance is too large mouth ring. Will cause the engine is pumped out of phase if the mouth is too narrow ring. Engine can be made. Will be late because of the ring. Because of heat expansion. Make ring bent. Walls made out of cylinders.

4, pump shaft (CONNECTING ROD).
Shaft with piston pump with crankshaft And are transmitted to the crankshaft end of the pump shaft with a small cylinder called a late end to the remaining crankshaft called late in the crankshaft to rotate at speeds in the end. Cause high temperatures. To prevent. ? deterioration caused by heat by the end of it consists of large bearings. The oil and some
This surge of oil from known oil to the piston within the cylinder to cool.
Assembly to be coupled to pump shaft. Otherwise the oil will make caulk (the side of the piston. RIM draw ?? bound directly to the prevention of errors. Pump shaft is marked in each set, the operation is that different types of machines so as to make inspection Repair Guide for detailed

5th crankshaft (CRANKSHAFT).
Drive to drive wheels of the vehicle. By drawing down the shaft of the pump and the rotation of the crankshaft crankshaft receive power from the shaft and piston pump spin speeds for this reason it is made from carbon steel, high-mix tips. a high resistance to wear.

Structure of the crankshaft of the illustrations below.

Future, the woman is supported by bearings crankshaft crankshaft’s room and crankshaft rotate around the Future is the Future, woman, each woman has the arm of the crankshaft. The crankshaft is installed on the crankshaft to the center axis of the skew axis in the form of encumbrance. To reduce the unbalanced force of the crankshaft rotation. While working on the engine crankshaft is known for a lubricant oil to the Future girl. Pump shaft bearings. Pump shaft and fasteners.

6 wheel power assist (FLY WHEEL).
Momentum wheels do help with the heavy cast iron with ?? Doc, late, with the crankshaft. Transmission for vehicles that are used in a regular rhythm of the engine explosion point. The piston is transmitted to the crankshaft only single strokes. Perry that the addition of the tempo, rhythm this other is lost due to friction wheel inertia force will continue to help force rotation (Inertia) during the other strokes apart from the explosion strokes. Rotate the crankshaft to continue to also make the engine work smoothly with the surrounding teeth fertility cycle the edges of the wheel idle wind power will help tackle the teeth of the drive motor start fertility. While starting up the engine. Gears used in automotive automatic power assist wheel is changed, a textile, Convergent Counsel

“The loss of inertia” refers to the loss is especially resonant in the compressed This occurs while the piston is moved up pressure compressed air and fuel mix.
Crankshaft bearings.
1, General Chapter lecture.
Crankshaft has been doing serious strength. (Gas caused by the ignition, piston And rotate at high speeds. For this reason, bearings needed to support the use of the crankshaft and woman, and Future oil to prevent stickiness death and loss of stiffness.
2 types of bearings.
Crankshaft and other parts that rotate at speeds and under a weighty burden to use support-bearings. The bearings-this Features good tolerance to wear. Performance and prevent contamination death. Bearings cortex consists of a metal. And surfaces of bearings made of metal type. Experience with a crankshaft for a block of metal shell to protect bearings from rotating bearings.
This has produced a many – Each type of meat is the material surface with different functions around the other to a metal white metal Clevestig fat Or aluminum.

Bearings each number is set bearings. To change the bearings will need to change the bearings to match the number of numbers that are changing the way the original number selected bearings. To study the repair manual.
1) the white metal.
Metal white metal ????????? zinc coated with tin or lead coated materials. It is seized of the island. But because it has less strength. Therefore often be used in engines has been not much
2) metal Clevestig fat
UK, fat metal surface is coated with copper metal. And lead, which is mixed with more strength and resistance to hunting as well as the white metal. But the island has been confiscated poor. Metal, UK, with a fat engine crafty And heavy load.
3) aluminum metal.
Surface aluminum metal which has a surface aluminum Tin and mixed mantle. Effective resistance to wear. And cooling better than the white metal and the metal Clevestig fat which are used with gasoline engines.

3, the gap of the oil bearings.
Face contact between the bearings on the crankshaft to rotate the need to send a sufficient amount of oil to lubricate the polish to prevent direct metal to metal ???. Therefore need a suitable gap between the bearings on crankshaft Enough oil to create a film of oil. Gap is called Oil gap. The size will vary according to type of engine but the way around.

Size is from 0.02 to 0.06 mm (0.0008 to 0.0024 inch)

Mechanisms tongue

4 strokes engine coupled with packed strokes strokes strokes suck explosive spitting exhaust strokes. But work is only 2 strokes of the tongue is attached rhythm and spew exhaust steam. Therefore, the mechanism design tongue To such work is 1 Rotate the cam shaft to run word of ID. Tongue and exhaust cam shaft to the second round will be 1 full duty work.
Flywheel ?? Times cherished possession. Will be combined in one end of the crankshaft. The flywheel ?? Times cherished possession of the cam shaft will seize on the end of the cam shaft. Exhaust cam shaft with the crankshaft is driving the belt. ID is the cam shaft drive gear that is the stickiness with ID and exhaust cam shaft (note from the picture above) the number of flywheel teeth ?? Times cherished possession cam shaft. Are many.
2 times the flywheel ?? Times cherished possession crankshaft cam shaft is rotated around the crankshaft rotate 1 Round 2 of the tongue will work balance And correct the rhythm of work. Will make the engine run efficiently. Tongue mechanism will vary depending on the engine in the system. We will illustrate the following
1st gear-independent and cherished possession.

Tongue-gear drive mechanism Times cherished possession. Used engine with a mechanical pump lid tongue beyond the cam shaft, however, the use of gear pump shirt Times cherished possession. The work will take more than noise-chain Times cherished possession by this method is not a word driver is used in modern gasoline engines.

2-chain Times cherished possession.

Mechanism driving tongue-chain, Tai cherished possession. This in-use engines over the cam shaft wall and pump cam shaft wall above the double pump. The cam shaft drive chain will be cherished possession Times. And is a lubricating oil. Tenseness of the chain will be adapted by the chains and set. The chains help reduce the pressure pulsation of the chain. Cam shaft to a chain drive is quieter than a gear and really cherished possession. Making are used when
Not too long ago.

3-belt, really cherished possession.

Belt drive mechanism, a tongue-Times, cherished possession. A cam shaft drive belt is a tooth replacement using chain Times cherished possession. Belt is quieter running chain. And do not require lubrication. Or adjust the belt tenseness also has less weight. How to drive a different word for this reason the engine is currently used in most

7th to sink oil ?? Stores (OILPAN).
Basin oil mentioned in a final order of the parts of a machine.

The bottom of the shirt called pump crankshaft The basin is an oil and stickiness is coordinating with liquid gasket or rubber gasket or packing paper. Basin oil to a steel plate. Block plan, and act ??? oil. Sink to the bottom when the car is not on the level and ??? speak out when the brake pedal in the immediate The gas station can be made to send oil to lubricate at all times. The oil will be filmed in the movie section of the basin bottom.
Basic principles of the engine 4 strokes

Resonant charge ID.
The rhythmic cadence of the air. And fuel into the cylinders, which are pulling tongues ID exhaust opening while closing word. As the piston moved down. Vacuum will occur in the cylinder and the mix of air and fuel is driven into the cylinder by atmospheric pressure.
Tempo jam
This is the rhythm, tempo of air and fuel is pumped. Both tongue and palate exhaust vapor tight engine while moving from bottom dead center to dead center will be pumped on the mix makes the pressure and temperature are increased to the point of explosion crankshaft one full rotation. when moving it around to center on death.
Cadency point explosion.
This rhythm is the rhythm engine powered car in production is due before the piston is moving to zero in on death strokes recorder will spark the spark plugs fire to the mix of air and fuel resulting in burn insurgency quickly. cause the gas pressure cylinder pressure to force a draw down.
This is the machine is motoring!
Spew exhaust strokes.
The rhythm of this gas will be burned exclusion from cylinders. Exhaust open and tongue out from the piston is moved up dead center to bottom dead center. Driving exhaust gases from the cylinder when the piston top dead center and moving it will start to charge ID rhythm again. Described from this point until the crankshaft rotate twice. And the engine will be a fully working routine. Quaternary cadency Cadency ID is attached packed ingredients. Explode and spit out the exhaust. This is the basic work of the four engine strokes.
Lubrication system.
Engine consists of a moving metal parts in many parts, each of which will combine the decidedly Those parts include pump shaft and crankshaft parts
Mechanisms tongue
When the engine starting rotation. Friction between these parts causes are job losses erode As well as the stickiness of the engine. Due to heat from the grate. Therefore, lubrication is sent to those parts. To prevent unwanted symptoms of them. The lubricant was sent pay.
The engine’s lubrication system that Picture below shows the mechanism of lubrication while the spin axis.

Role of lubricant
1) will create a coating of lubricant oil over the surface of metal joint To prevent exposure. Direct metal It also reduces traction to occur least And to prevent wear. And the heat.
2) allows parts of the engine oil cooling.
3) enables the prevention of oil leakage between the piston And a cylinder.
4) bring oil from the engine grime.
5) oil prevent parts from corrosion.

Type of lubrication system.
Oil is sent to pay the moving parts of the engine such as a multiple-pressure-??? as a whip and sprinkle with a pressure ??? together. The only way a pressure is applied to the motor current. In-pressure lubrication system. Oil pressure is caused by a gas station and send forces to the movement of engine parts.

The flow path of a lubricating system pressure as shown in the illustration below.

Gas Stations.
Station suck up oil from oil basin. Make the oil pressure up and down to the movement of engine parts. Sometimes ??? will be driving the crankshaft and the sometimes eccentric shaft or belt to get a rude filter will be installed at the entrance of the petrol station to filter out dirt, oil
Gear-pump-pump and call Soi? Pump is a two-to

Basic Understanding Why Your Car’s Engine Misfires

Your vehicle’s engine goes through a combustion process thousands of times each minute. Air and fuel are sent to each cylinder’s combustion chamber where the mixture is compressed. Coil voltage travels through a spark plug that is located at the top of each chamber. The spark plug ignites the compressed mixture, which provides the necessary energy to move your vehicle down the road. When a misfire occurs, the event affects your car’s performance, efficiency, and overall drivability.

This article will explore the reasons your engine might suffer a misfire. We’ll take a look at problems involving a loss of spark, unbalanced air-fuel mixture, and compression leaks. I’ll explain the factors that can contribute to each of these issues.

Loss Of Spark

A loss of spark can be due to fouled spark plugs, bad wires, or a distributor cap that has developed a crack. Plugs should normally be replaced every 40,000 miles. Even those that are advertised as being capable of lasting 100,000 miles should be replaced long before that marker arrives. Besides expiring due to normal use, oil deposits can build on the electrodes, preventing voltage from jumping the gap.

Spark plug wires are critical because a fouled wire will prevent voltage from reaching the plug. If that happens, the plug will be unable to ignite the compressed air-fuel mix in the associated cylinder’s combustion chamber.

If the distributor cap is cracked, the voltage may be unable to travel properly between the rotor tip and the terminals. Here too, this can prevent the plug from receiving the voltage necessary for ignition.

Unbalanced Air-Fuel Mixture

For several reasons, the air-fuel mixture within the combustion chamber can be too lean. When this occurs, there is an insufficient amount of gasoline to provide an efficient burn. This might be due to a fuel pump that is failing, a fuel injector that has formed an obstruction in the nozzle, or even a leaking exhaust gas recirculation (EGR) valve. Each can prevent sufficient fuel from reaching the cylinder’s combustion chamber.

There may be also be cases in which the mixture is too rich. Rather than an insufficient amount of gasoline preventing an efficient burn, there is too much in the chamber. This problem is far less common than a lean mix. When it occurs, it is usually due to a leaking injector.

Compression Leak

If a given cylinder’s chamber is suffering from a loss of compression, that means it is losing a portion of the air-fuel mixture before it can be ignited. This problem can usually be narrowed down to two potential root causes: an exhaust valve that has formed a leak or a blown head gasket. If you’re able to identify misfiring within multiple cylinders (and you have confirmed your spark plugs are fine), the issue is likely the head gasket.

A loss of compression can be confirmed by performing a leakdown test. It is a simple test that will help you identify whether compression is being lost through an exhaust valve with a deteriorating ring. This is a test you can do on your own rather than hiring a mechanic for the job. Most auto supply stores sell a special gauge that is inserted into the suspected cylinder’s spark plug hole.

Misfires can be serious. If you’re driving a small 4-cylinder car, a single misfiring cylinder can reduce your engine’s power by 25 percent. You’ll feel it shaking at idle. If the problem is severe, your engine may even stall. Even if your engine has eight or more cylinders, a steady misfire can reduce its fuel efficiency and impact its overall performance. Moreover, your car will fail an emissions test.

If your engine is misfiring, test the spark, air-fuel mixture, and perform a leakdown test for compression leaks. With a little time and effort, you can successfully narrow down and fix the root cause.

An Introduction to Inductive Ignition Systems

Inductive ignition systems have existed since 1908, developed by Charles Kettering who also developed the first practical engine driven generator.

The design has been improved over the years but the most significant recent development has been the introduction of Insulated Gate Bipolar Transistors (IGBT); these have allowed the design of extremely accurate, high spark energy inductive ignition systems.

A single operation is carried out by a transistor turning on the current to the ignition coils primary winding. This ‘charging’ stores energy in the coils magnetic circuit. The current is then switched off. As the magnetic field begins to collapse the coil tries to resist the drop in current causing the voltage in the secondary winding to rise rapidly, this high voltage breaks down the air/fuel mixture in the spark gap allowing a spark to pass, causing ignition of the air/fuel mixture.

The most significant advantage of inductive ignition systems is that inductive coils are generally more efficient than capacitive discharge coils as they can provide longer spark duration that can ensure complete combustion, especially on lean burn and turbo charged engines. The ability to provide longer spark duration is because inductive coils only provide enough energy to cross the spark gap; the remaining energy from the ignition coil is used to maintain the spark. Capacitive discharge coils release almost all of their energy instantaneously, therefore considerably reducing the amount of energy available to maintain the spark.

With inductive ignition systems more energy can be delivered to the secondary winding of the coil than in a capacitive ignition system. In fact, with the same power supply current draw, up to five times more energy can be delivered to the secondary winding of an inductive ignition coil than to a capacitive discharge coil. Typically a capacitive discharge system will deliver a maximum of 10 millijoules of energy compared to an inductive ignition system delivering more like 50 millijoules of energy and potentially in excess of 100 millijoules. This large difference in supplied energies will mean an inductive system can provide spark duration of 2000 microseconds or more in a single spark, compared to 600 microseconds for a capacitive system.

With inductive ignition systems the time taken to charge the ignition coil is called the ‘Dwell’. This dwell can be increased or decreased for differing engine applications. If longer spark duration is required to improve combustion of lean mixtures or engines with large cylinders the dwell time is increased, inputting more energy into the primary coil. Dwell time is decreased when there is more than enough spark energy to combust the mixture, this decrease will reduce spark plug wear, therefore increase spark plug life.

The high energy and long, programmable spark durations are a considerable advantage since they provide better ignition of lean or non-homogenous air/fuel mixtures. In many cases engines that are unable to meet emission standards with capacitive discharge systems can be bought into compliance with electronic inductive ignition systems such as those manufactured by Gill Instruments.

How to test a car spark plug

Spark plugs are important components in system of a car. Spark plugs enable the proper functioning of a car engine and perform the function of compressing fuels by the use of an electric spark. Although spark plugs wear out gradually, the user should ensure that the spark plug is of high quality in order to ensure longevity in performance. A car user is advised to take his vehicle for regular engine servicing. Regular engine servicing enables the mechanic to detect on any impending irregularities in the car. The car user is also advised to replace their car spark plugs after every two years.

So here is what you do.

Spark plugs are important components in system of a car.

A clear indicator that the car has a faulty spark plug is when the engine slows down on its performance. This is an obvious sign that the spark plug is worn out. Before the user replaces the worn out car spark plug, they should first check the manufacturer’s description of the car spark plug. The manufacturer’s description gives the exact specifications on the original car spark plug and alternative ones in case the user does not find the original type. In order to ensure that the spark plug is completely worn out, the user should test it first. Testing is normally done by the use of a spark plug gauge. Other areas to check on include spark plug cables which indicate any splits, cracks, rust in the engine as well as any other damaged area of the engine.

The car owner or the mechanic should take precautions against the risk of shock by wearing rubber gloves before they start on the task. The mechanic is also advised not to lean against the vehicle while the engine is still running. The owner/ mechanic can then start by testing the car spark plug functionality by dismantling each plug from the car engine. Dismantling of the car spark plug is done by the use of a ratchet wrench. With the use of the ratchet wrench, the user is advised to turn the spark plugs in an anti- clockwise direction. This is done while the engine is still running. When the engine starts to slow down, then the owner of the vehicle should know that the spark plug is still in good condition. If the engine does not react in any way after the spark plugs have been disconnected, then the spark plugs need immediate replacing.

The next step is removing the spark plug wires. This is done after the engine has cooled down. The owner of the vehicle can then test to see if the spark plug ignition is working. He can do this by exposing the spark plug wire to a metal surface. The spark plug will then emit a spark. This is an indication that the spark plug is in good condition. This action should be repeated for every other spark plug wire. Spark plugs should be also be cleaned regularly so as not to hinder on their performance. The owner/ mechanic of the vehicle should check to ensure that the spark plugs work well and then do another test on the same.

How To Test A Car Spark Plug

One of the important components in the system of a car is the spark plugs. They are basically a high voltage bridge for electricity, when the electricity crosses the bridge that is actually a gap between two contact points inside the engine; the spark is made by it that ignites gas vapors which makes the engine to roar.

Spark plugs enable the car to function properly and also perform the function of compressing fuels by the use of an electric spark. Although the efficiency of the spark plugs decrease gradually, it must be ensured that the plug is of high quality to guarantee its better performance. The vehicle’s user must ensure its regular engine servicing. When an engine is regularly serviced, the mechanic can detect any faults in it. It is recommended that spark plugs must be replaced after every two years or even earlier if needed.

Following is what can be done.

Spark plugs are vital components of the car’s system. When a car’s engine slows down in its performance, it is a clear indication that the plug has become faulty. This means that the plugs are worn out. Before the worn out plugs are replaced, the manufacturer’s description they should be checked first. That description gives the exact specifications of the original car spark plug and also suggesting alternative ones if the original ones cannot be found. For ensuring that the plug is completely worn out, it needs to be tested first. A spark plug gauge is generally used for testing the spark plugs. Other areas for checking include plug cables as they indicate any cracks, splits and rust in the engine as well as any other damaged area of the engine.

Precautions must always be taken by the car owner or mechanic against risks of shock by wearing rubber gloves before starting the task. The mechanic must not lean against the vehicle while in a running condition. The functionality of the spark plugs can be tested by removing each plug from the car’s engine. A ratchet wrench can be used to remove the plugs. The user should turn the plugs in an anti- clockwise direction by using the ratchet wrench. This has to be done while the engine is still running. The owner of the vehicle will know that the plugs are still in good condition when the engine with start to slow down. If there is no reaction in the engine in any way when the plugs have been removed, then the plugs need to be immediately replaced.

The next step is to remove the wires of the spark plugs. This has to be done only when the engine has cooled down. The spark plugs can be tested if their ignition is working. It can be done by exposing the plug wire to a metal surface. If the plug emits a spark than this is an indication that the spark plug is in good condition. This procedure has to be repeated for every spark plug wire. It is necessary to clean the spark plugs regularly so their performance is not hindered. It can be further endured if the spark plugs work and another test can also be done on the same.

How To Test Ignition Coils

Preparation for Ignition Coil Test

The first thing you want to do is always take the necessary precautions. When working near or around a running engine one must exercise great caution. You should be aware of any loose clothing. If you have long hair you want be careful that it does not make contact with any part of your car’s engine and its moving parts.

Testing the ignition coil on your car is one of the fairly easier tasks to perform. It’s not that complex nor does it require any special tools or equipment. One thing to keep in mind is that your ignition system produces a great amount of electricity. Should anything go wrong, the result could be very dangerous. Proceed cautiously.

If your coil has already been removed from your vehicle and you need data that is more specific about your ignition coil, you can perform what is called a bench test. Set up the bench test by removing the one spark plug wire from its plug. Then remove the spark plug with a plug socket. Now you want to connect that spark plug back to the spark plug wire. Do this with great care; you don not want anything to fall into the empty spark plug opening or you’ll have a problem.

Testing the Ignition Coil: The Bench Test:

Grab a pair of insulated pliers. Hold your plug wire with insulated pliers. Now, you need a grounding point so look around your engine for one. You want a spot that is easy to access and that has exposed metal. You could even use the car’s engine for this.

Hold the spark plug wire with your insulated pliers and make contact with your chosen grounding spot with the threaded part of your spark plug. Have some one start your car’s engine and pay attention to the spark plug gap. You are looking for a bright blue spark to jump across the gap – the electricity. If you can observe this blue spark clearly, even in daylight, then your spark plug is working just fine.

Testing the Ignition Coil: The Multimeter Test

There are a number of other tests you can perform for your ignition coil. However, if you want accurate information on the status of your ignition coil then you should perform a multimeter test. This test is far more accurate in determining whether you need to replace the coil or not. It is considered the only proper test for a coil.

You could rely to an extent on the bright blue spark you see in your bench test but if that spark is somewhat weak and your eyes can’t really tell, using this spark plug can cause your vehicle to run rough or incorrectly which is the last thing you want.

Let go inside the ignition coil for a moment. The ignition coil contains two coils of wire that are right on top of each other. We refer to these coils as windings. There is a primary winding, the first wire, and a secondary winding, the second wire. The primary winding collects the electricity to create the spark. The secondary winding sends it out to the distributor. It is possible for either of these windings to malfunction causing your vehicle’s ignition coil to fail. Sometimes an ignition coil can completely fail meaning it makes absolutely no spark whatsoever.

A multimeter test is performed with the ignition coil completely disconnected. This meter provides numbers to help you determine the status of the coil – far more reliable than a visual assessment. There are different types of digital multimeters and they can be found online or at your local auto repair retailer.

Of course, to use the multimeter, you will have to know the resistance specifications for your ignition coil. If you don’t know what they are then refer to your vehicle’s service or repair manual for that information.

Testing the Windings

To test the primary winding of your ignition coil:

As mentioned above, the primary winding of the ignition coil first collects the electricity or voltage from the car’s battery. Have you found the resistance specification for your ignition coil? You will need this before performing the multimeter test. If you do not have them take a moment to locate you service or repair manual for that information.

Once you have found the resistance specifications, locate your digital multimeter. If you have a traditional round coil, you will need to use the multimeter and place the leads on the small, outside poles of your ignition coil. If you have one of the newer enclosed units, then place the leads on indicated or marked poles of your coil.

Observe the reading you get on the multimeter. If the multimeter reads within the range according to the specification in your service manual, then your primary winding is functioning well and you can go on to check the secondary winding. If you find the reading to be even slightly out of the range then you should replace the ignition coil.

To test the secondary winding of your ignition coil:

The secondary winding of your ignition coil sends the spark to your distributor and then to the spark plugs. A weak spark or no spark at all is an indication that the coil needs to be replaced.

To test your ignition coil’s secondary winding, attach the probes to the outer 12V pole and the center pole of your ignition coil. The center pole is the spot where the main wire is located that connects to the distributor. Again, check the reading to make sure they fall within the specified range as indicated in your car’s service manual. If your coil falls within that range all is well. If the reading should fall even slightly out of the specified range, then you should replace your ignition coil. Remember a failing ignition coil will cause your engine to run rough and can cause other problems as well.

Spark Plug Troubleshooting Methods

There are two methods to troubleshooting spark plug wires. The first is the backyard mechanic technique, which is simple and only requires basic hand tools, while the other is a more sophisticated method that requires a multimeter.

Quick Troubleshooting

If you don't have a multimeter, follow this method. Begin by removing the spark plug cover on the valve cover. Then pull the spark plug wire off the spark plug with a spark plug puller or needle nose pliers. Be sure to pull from the base of the wire, because they tend to seize onto the spark plug. If you don't pull from the base of the wire, you risk breaking the wire and getting it stuck on the plug, which then becomes very difficult to remove. Next, connect an extension and spark plug socket to your ratchet, and remove the spark plug. Then place the spark plug back in the wire and place it next to a good engine ground. An engine ground is any metallic object connected to the chassis of your vehicle. Next, have a helper crank the vehicle while you observe the spark arcing from the spark plug to the engine ground. If the spark is dark blue, then you know the wires are good. If the spark is faint and yellow, you could have a faulty spark plug wire. However, this technique isn't very accurate for pinpointing the problem that might be affecting your vehicle. A more consistent and accurate method is to use a multimeter.

Multimeter Troubleshooting

If you don't have a multimeter, it is highly advisable to purchase one as it comes in handy for electrical troubleshooting. To check if the wire is faulty, set the multimeter to the "Ohms" setting and connect the black lead to one side of the spark plug wire and the red lead to the other side of the wire. You should see about 5,000 Ohms of resistance per foot of wire. This is a general rule of thumb, and will vary from vehicle to vehicle. But what is important and what you really need to look for is for an Ohm reading out of the ordinary. If the multimeter reads "Infinite" or "Ouch," then it is telling you that there is a break in the wire and that it should be replaced. If the multimeter reads an excessive Ohm reading, more than the specifications for your car, the wire should also be replaced in this scenario.

How to Check the Resistance of a Spark Plug Wire

When your car engine isn't running right, or misfires, start by diagnosing the spark plug wires. Too much resistance in the wire leads to less electrical current getting to the plug. Reduced electricity results in not enough spark to ignite the gasoline mixture that fires the engine. With a multimeter, it takes just a few minutes to measure the resistance of each plug wire.


Step 1
Remove both ends of the spark plug wire--from its connection with the plug and its connection with the ignition coil.

Step 2
Check a repair manual for your make and model to find your spark plug wire resistance range. The measurement will be in kilohms.

Step 3
Place the multimeter dial setting on "ohms (Ω)" for auto-range multimeters. Turn dial to the "ohmmeter (Ω)" section of manual range multimeters, then choose the closest setting that is greater than your plug wire's correct resistance. For example: For a 15-19k resistance range, turn the dial to "20k." For a 21-25k range, turn the dial to "200k."

Step 4
Touch one lead from the multimeter to the metal center of one of the spark plug wire connectors. Start with either end, as the wires are not polarity-sensitive.

Step 5
Connect the second lead to the other end of the plug wire, once again touching metal to metal. Hold in place.

Step 6

Take a reading in kilohms (1 kilohm=1,000 ohms). If it falls within the manufacturer's measurement range in your repair manual, the plug wire is not your problem. Higher readings indicate too much resistance, possibly because of rusting or faults in the wire. A broken wire allows no electricity reading at all, which will cause the multimeter to register resistance as "over limit."