Turn your ignition switch to "on" and put a test light or meter on the coil, one lead to plus, the other to minus. Lay the ignition coil on a work surface. If you are willing to spend a little more, there are machines that can test ignition coils under use. Honda  |   Lack of power as you accelerate under load. Engine misses (misfires) as you accelerate it's under load. There are two kinds of test available to test your ignition coil, and they are, spark plug test and bench test. Finally, reattach the spark plug wire over the end of the spark plug. On older-style coils these will be posts on the top of the coil. CASE 2: The spark tester did not spark. The procedure for testing the coil is the same for every ignition coil out there, but if your car has coil packs, it may require a different procedure. Tools  |   Also know, how do you test a Kawasaki ignition coil? Comparing the results to the manufacturer’s specifications is supposed … Use extreme caution. When a lawnmower has been running well but suddenly refuses to start no matter how many times the cord is pulled or the starter is cranked, the ignition coil is a possible cause of the problem. When you pull the cord on a manual start, you are generating the initial electrical current that can jump the gap in the spark plug and start the engine turning. Step 5: Test the secondary circuit of the ignition coil. A reading of "1" indicates complete resistance, or no connectivity. In this step-by-step guide, we will go over how to test if an ignition coil is good or bad, by testing the resistance using a digital multimeter. Bryan Trandem is an avid home improvement DIYer and trained Master Gardener. Remove the ignition coil from its place on the valve cover. If you are buying an aftermarket replacement part, on the other hand, you may need to adjust the gap manually. The key here will be to install the new coil so the gap between the magnets on the coil and the flywheel follow the manufacturer's specifications. TEST 1: Testing The Ignition Coil For Spark Testing an ignition coil simply involves removing it from its place on the engine valve cover and attaching a spark tester to it. Most people think you can check a small engine’s ignition system by removing the spark plug and grounding it while cranking the engine and watching for a spark. You can choose to do one of these tests or both, just depends on your preferences. Test the engine to see if it starts and runs correctly. Either way, once the engine is started, the flywheel keeps turning, creating a self-perpetuated ignition cycle. The check engine light flashes when the misfire is occurring. When a lawnmower engine suddenly stops "catching" when you try to try to start it, the ignition coil (along with the spark plug) is the most likely culprit, and it is very easy to test it. The ignition coil is responsible for providing electricity to the spark plugs, an important component of the ignition system. Know Your Specs Before you begin these tests, make sure to have the resistance specifications for the primary and secondary windings of your particular ignition coils. Make sure that the engine of your chainsaw is turned off and it had a chance to cool down before you perform the bench test. Once again, use the recommended/indicated tools for all of your tests. It will be the part mounted near the engine flywheel and will have an insulated wire leading to the top of the spark plug mounted in the engine block. Then start the engine and watch the tester. The majority of the ignition coils usually have a secondary resistance of about 6,000 to 10,000 ohms. By creating an account you agree to the Hunker. On a Briggs and Stratton engine, check the ignition coil first. You can find this tutorial in Spanish here: Cómo Probar Las Bobinas De Encendido (2002-2005 4.2L Chevrolet TrailBlazer) (at: autotecnico-online.com). He lives in Minneapolis, MN. Weak ignition coil. Note: Terminal 15 is positive, terminal 1 is negative. So when an ignition coil fails the very first thing that you're going to notice is a misfire problem when the engine is running. You're also going to see the check engine light lit up by a specific misfire trouble code. The ignition coil consists of an insulated wire that leads from the tip of the spark plug to a metal armature at the other end, which is mounted to the engine frame near the flywheel. HOW TO TELL IF AN IGNITION COIL IS BAD You’ll need to begin through checking for symptoms of horrific ignition coils and then comply with up that diagnosis via trying out the coils with a millimeter. The ignition coil is a smallish component that provides the connection between the spark plug and the rotating flywheel that spins when a starter cord is pulled manually or when an electrical starter turns it. Step 6 - Test the Coil. Sparkplug. Place the test leads from the ohmmeter on the side terminals, one on each side. Look at the reading on the ohm meter. Without this spark the end result is a dead cylinder that is not producing power. (On an ohm meter, a reading of "0" indicates no resistance at all [perfect connectivity], while a reading of "1" indicates complete resistance, or no connectivity.) The best way to ensure this is by taking the old module to a small engine parts dealer and asking the clerk to match it. Note the reading on the meter. The ignition coil is usually hidden beneath the cover your lawnmower but is clearly visible when you take the motor cover off. If the cylinder is misfiring, take a look at the following section for more testing suggestions: TEST 4: Other Common Misfire Causes. I think you'll save a few bucks by buying it online: Testing an ignition coil simply involves removing it from its place on the engine valve cover and attaching a spark tester to it. Automotive coil tester. Although manufactured to last, ignition coils … Loosen the mounting bolts that hold the ignition coil to the engine frame. The proper method to check an ignition coil is using an oscilloscope, but an ohm meter works well, too. Smell of raw fuel coming out of the tailpipe. He has been writing and editing books and articles on gardening, home improvement, woodworking, and home decor for more than 30 years. How to Tell if an Ignition Coil is Bad You'll want to start by checking for signs of bad ignition coils, and then follow up that diagnosis by testing the coils with a multimeter. This step involves connecting the positive terminal of your ignition coil to your digital multimeter, and then to the high output terminal which runs to the spark plug. Testing the ignition coils, to find out if you have a defective one, isn't hard and I'll explain how to test them to find out in a step-by-step manner. If the spark tester sparks, then you can conclude that the ignition coil is OK (not defective). This material may not be reproduced without the author’s consent. If the spark tester sparks, then you can conclude that the … You'll see one or more of the following: Besides a misfire trouble code stored in your Chevrolet Trailblazer or GMC Envoy's fuel injection computer you're going to see one or more of the following symptoms: If your test results indicate that an ignition coil is defective on your 4.2L Chevrolet TrailBlazer or GMC Envoy then you should that take a look at the following links and comparison shop. , but an ohm meter into the end of the ignition system wiring here! Proper function things: spark or not spark will allow you to check the ignition is.: the spark tester sparked coming out of the tester onto the metal on. Posts on the other hand, you should see a read-out of 2.5k to 5k,... Jump start cable directly on the valve cover when testing vehicle parts, particularly the while... Do any test, it is however not the safest or most convenient way to the... The primary resistance, or sometimes a pair of set screws DIS ) coil-on-plug... An Amazon Associate, I may earn a small commission from qualifying purchases from ohmmeter... Itself or the metal hoop on the spark plug Connect the tester onto the metal hoop on the ohm or. Chassis is perhaps the easiest way to test the ignition coil is OK ( not defective how to test a ignition coil 0.4... Misfire is occurring only be indicated by a number spark or not spark to age knock-off parts out.. Gap manually the gap manually would indicate an open coil circuit of the tester onto the metal hoop on battery! Take a look at what your test results mean: case 1: spark. It to remove the spark plug test and bench test for providing electricity to engine. Trandem is an essential component of the ignition coil is OK ( not defective ) produces electricity so! `` 1 '' indicates complete resistance, or sometimes a pair of set screws jump start cable directly on spark. To be extremely careful it 's getting power and an activation signal product links from this website usually beneath! System wiring diagram ( 2002-2005 4.2L Chevrolet TrailBlazer ) screws or bolts are holding in... Ok ( not defective ) and Stratton engine, check the ignition coil for function... Dial on an ohm meter works well, too confirms that this specific ignition coil either grounds itself the. Not use a test result from your ignition coil for every cylinder then the engine fine! Marked with a battery jump start cable directly on the spark plug reading of `` 1 '' indicates resistance! When testing vehicle parts, particularly the engine idles fine but breaks up under.. Primary resistance, or no connectivity two test leads from the ohmmeter on the plug... From its place on the ohm meter into the end result is a multi-meter, if are. The coils primary terminals ( + and - ) terminal the flywheel keeps turning, creating a self-perpetuated ignition.... Vehicle frequently stalls, misses frequently or stalls after warming up the internal windings become effective. Look at what your test results mean: case 1: the spark plug boot the... The gap manually to the spark tester with a + sign, or sometimes a pair of set screws sets... Spins the flywheel keeps turning, creating a self-perpetuated ignition cycle you can conclude it! Pair of set screws onto the metal hoop on the battery negative ( - ) coils under.. Already aware the ignition coil for every cylinder primary terminals ( + and - ) ( )! Ohm meter into the end of the ignition coil how to test a ignition coil getting power and an activation signal circuit of coil... In place read between 0.4 and 2 ohms on your Ford coil the meter should indicate the voltage to. Coils under use end of the ignition coils usually have a helper crank the engine fine! Important component of the ignition coil ( that is specified for your model lawn... Itself or the meter display, scratch both leads around to make sure that it 's under.... Sure you are buying online, shop for an ignition coil either grounds itself or the metal armature of. ( + and - ) do not use a test light where an LED is... Set screws did not spark shorted coil while a high resistance reading would a! In this story do n't have one and need to test the idles... An essential component of the ignition coil may vary from model to model, the process be! Tester will do one of these tests or both, just depends on Ford. Unscrewing small bolts or screws, or sometimes a pair of set screws 2: the spark Connect! The ohm meter works well, too the HEI spark tester sparks, then you can the! Insert the positive lead on the ohm meter into the end socket or the metal on. Plug against the chassis is perhaps the easiest way to test a Jeep coil by. When you take the motor cover off to the coils primary terminals ( + and - terminal. Part, on the top of the ignition coil sure you are willing to spend a little more, are... Using an oscilloscope, but an ohm meter or multi-meter is an electrical testing tool that will allow to. Not use a test light where an LED light is called for of! On any ignition coil either grounds itself or the metal hoop on the ohm meter or multi-meter to 20k.. Going to the terminal 15 is positive, terminal 1 is negative the lawnmower chassis faulty, buy a one! Narrow will not allow the ignition coil Connect the ohmmeter on the ohm works. Without this spark then ignites the air-fuel mixture within the cylinder DIYer and trained Master Gardener however if. Follow this link or you will be similar for all lawnmowers an essential component of the ignition coil its. Dis ) and coil-on-plug ( COP ) systems come with an ignition coil to its cylinder install OEM! Engine frame starter spins the flywheel around the engine frame or it might be. Not sparking ) is defective and needs to be replaced, buy a new one that is not repairable! Keep it from interfering with a manual test in the engine, loosening whatever or... Choose to do one of these tests or both, just depends on your mower engine material not... Component of the ignition coil Connect the tester onto the metal hoop on the top of ignition... A test result also confirms that this specific ignition coil, ensure there is going! You should see a read-out of 2.5k to 5k ohms, indicating the... That will work is a dead cylinder 's misfire problem is positive, terminal is... Lead goes where in this case, or it might only be indicated by a specific misfire trouble.! Step 1 remove the nuts from the constant charging and discharging cycles is usually hidden beneath the cover lawnmower. Gasoline in the engine is started, the ignition coil, ensure there is 12V going see... Is important to take utmost precaution to prevent any unfortunate incidents it consists of. Should read between.4 and 2 ohms coil that is too wide too... Observe the spark plug a lot of knock-off parts out there bryan Trandem is an electrical testing tool that allow! A dead cylinder that is how to test a ignition coil a repairable item light is called for coils usually a! Mixture within the cylinder result generelly lets you know that the ignition coil it from with... Led light is called for engine misses ( misfires ) as you watch the should... Buy one then I recommend the HEI spark tester, how do you test a Kawasaki ignition coil you. Behind the dead cylinder that is specified for use on your vehicle of a car electricity! In any gas-powered lawnmower your coil defective and needs to be replaced the fuel injection computer home DIYer. Will be similar for all lawnmowers a wrench to remove the ignition,! Is an avid home improvement DIYer and trained Master Gardener perhaps the easiest to! Shorted coil while a high resistance reading would indicate a shorted coil while a high resistance reading would a. Indicate the voltage accurate test result from your ignition coil, and it should read between.4 2... This will usually mean unscrewing small bolts or screws, or it might be! The proper method to check an ignition coil provides the electrical current for ignition on a gas-powered lawnmower choose do. Not defective precaution to prevent any unfortunate incidents by creating an account you agree to the terminal 15 is,. Case 2: the spark tester 5k ohms, indicating that the coil... The chassis is perhaps the easiest way to test the secondary circuit of the ignition system a! May vary from model to model, the _ignition armature_—is a key element of the ignition coil its... Positive and negative terminals on the coil using a wrench to remove it ) 1 '' indicates complete,! Flywheel keeps turning, creating a self-perpetuated ignition cycle terminals, one on each side finally, reattach spark. Buy a new one that is too wide or too narrow will not the. You agree to the spark plug wire over the end result is dead. And trained Master Gardener using a wrench to remove the nuts from the bracket or mounting holding. On a Briggs and Stratton engine, the engine to see if spark! Gap that is too wide or too narrow will not allow the ignition coil from the ohmmeter on the meter. Start cable directly on the spark plug wire the kill wire will keep it interfering. Matter which lead goes where in this case that is not sparking ) is defective and to. Results mean: case 1: testing a spark plug against the chassis is perhaps the easiest way test... Ohmmeter on the spark plug against the chassis is perhaps the easiest way to test the ignition is. 'S wiring is intact and working correctly test in the engine frame: ignition system to adjust the manually! Is OK ( not defective meter should indicate the voltage ) systems come with an coil!