All Rights Reserved. Note the reading on the meter. 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. 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. This will usually mean unscrewing small bolts or screws, or sometimes a pair of set screws. What the Coil Does . 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. On older-style coils these will be posts on the top of the coil. As an Amazon Associate, I may earn a small commission from qualifying purchases from the Amazon product links from this website. If the spark tester sparks, then you can conclude that the … When installing the ignition coil, attach the ground wire (if there is one) first, then the armature end, following the manufacturer's recommendation for the proper gap between the armature and the magnets on the lawnmower flywheel. Step 6 - Test the Coil. Though its precise location may vary from vehicle to vehicle, generally, it is located near the fender or bolted to a bracket fairly close to the distributor. 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. It consists generally of two sets of wires that are wrapped around an iron core. This is a completely safe method that will work on any ignition coil. Hunker may earn compensation through affiliate links in this story. Place the test leads from the ohmmeter on the side terminals, one on each side. An ohm meter or multi-meter is an electrical testing tool that will allow you to check the ignition coil for proper function. Comparing the results to the manufacturer’s specifications is supposed … Old-timers and very experienced backyard mechanics may swear by this method, but it has some small inherent danger of shock and fire, so our technique involves removing the ignition module and testing it with an ohm meter, a common electrician's tool. Do NOT follow this link or you will be banned from the site! Phillips screwdriver. Then the engine is cranked to see if the spark tester sparks. If the cylinder is misfiring, take a look at the following section for more testing suggestions: TEST 4: Other Common Misfire Causes. Removing the kill wire will keep it from interfering with a manual test in the case of a faulty switch. Part 1 of 1: Testing a spark plug ignition coil. Step 5: Test the secondary circuit of the ignition coil. However, if you install an OEM (original equipment manufacturer) replacement part, achieving the correct gap should be automatic. In many instances, you may not … The check engine light flashes when the misfire is occurring. You're also going to see the check engine light lit up by a specific misfire trouble code. As with most types of vehicular maintenance, you'll want to begin the test with the vehicle in park and with the engine off. Let's take a look at what your test results mean: CASE 1: The spark tester sparked. Another diagnostic tool that will work is a multi-meter, if set to measure resistance. The armature essentially consists of two hidden coils of copper wire that generate electricity when magnets along the outer edge of the flywheel whiz by the coils at high speed. On a Briggs and Stratton engine, check the ignition coil first. Before checking the ignition coil, ensure there is 12V going to the terminal 15 on the coil. Remove the center wire that runs from the coil to the distributor, then remove any wires connected to the positive and negative terminals on the coil with a wrench. The ignition coil is responsible for providing electricity to the spark plugs, an important component of the ignition system. Some service technicians use a thin piece of cardboard, such as matchbook cover, to establish this gap, but a spark plug gapping tool will also work. 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. Where To Buy The Ignition Coils And Save. There are a lot of knock-off parts out there. 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. Ideally, you should see a read-out of 2.5k to 5k ohms, indicating that the coil's wiring is intact and working correctly. 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. 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. In all these cases, the ignition coil either grounds itself or the internal windings become less effective due to age. Use extreme caution. (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.) When testing vehicle parts, particularly the engine, you need to be extremely careful. Do not use a test light where an LED light is called for. It's impractical to uncover the coil and examine the wire; fortunately, there's an easier way to find a break -- a continuity test. Disclaimer. Honda  |   Then start the engine and watch the tester. Lack of power as you accelerate under load. CASE 2: The spark tester did not spark. Most later models use Briggs and Stratton's magnetron coils—essentially a self-contained ignition system that derives its power from the magnets on the flywheel.Testing one of these coils constitutes a relatively simple process. If you are willing to spend a little more, there are machines that can test ignition coils under use. An ignition coil is a kind of high-voltage transformer. Also, the engine of a car produces electricity, so you will want to take utmost precaution to prevent any unfortunate incidents. Bryan Trandem is an avid home improvement DIYer and trained Master Gardener. Touch the red lead on the ohm meter to the spark plug connection and touch the black lead to the armature on the ignition coil. This is the correct and expected test result and lets you know that the ignition coil that you're testing is not defective. You can find leaf blower ignition coils here. If the ignition coil has a ground wire, also loosen and remove this at the point it attaches to the lawnmower chassis. The spark tester will do one of two things: Spark or Not Spark. The ignition coil consists of a single wire wound hundreds of times around a core, and any break that occurs in the wire renders the coil inoperable. 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. There are two coils of wire, termed windings, within an ignition coil. Once again, use the recommended/indicated tools for all of your tests. Most coils should read between 0.4 and 2 ohms. This test result generelly lets you know that the ignition coil (that is not sparking) is defective and needs to be replaced. 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. Finally, reattach the spark plug wire over the end of the spark plug. 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. Tip. How to Test a Jeep Coil Pack by Dustin Thornton . To test the resistance of the coil in your chainsaw which is called a bench test, take your multimeter and remove the coil from your chainsaw to get easy access to its electrical terminals. It does not matter which lead goes where in this case. This material may not be reproduced without the author’s consent. Insert the positive lead on the ohm meter into the end socket or the metal hoop on the spark plug wire. The majority of the ignition coils usually have a secondary resistance of about 6,000 to 10,000 ohms. Another simple test you can do, regardless of the type of coil you're dealing with, is to check the voltage flowing with battery connected. If the ignition coil is faulty, buy a new one that is specified for use on your mower engine. Lay the ignition coil on a work surface. 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. This spark then ignites the air-fuel mixture within the cylinder. Set the dial on an ohm meter or multi-meter to 20k ohms. The ignition coil provides the electrical current for ignition on a gas-powered lawnmower. Turn the vehicle off and open the hood. 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. The issue here is a coil that has worn out from the constant charging and discharging cycles. The ignition coil on a Harley Davidson motorcycle is an essential component of the ignition system. Measuring ignition coil resistance was once a popular test method. This indicates an ignition coil that has failed. And distributorless ignition systems (DIS) and coil-on-plug (COP) systems come with an ignition coil for every cylinder. On an electric start motor, a battery-operated starter spins the flywheel. Loosen the mounting bolts that hold the ignition coil to the engine frame. Terms of Use There are two kinds of test available to test your ignition coil, and they are, spark plug test and bench test. Also know, how do you test a Kawasaki ignition coil? To test the ignition coil connect the ohmmeter's two test leads to the coils primary terminals (+ and -). Automotive coil tester. Ignition coils take energy from the battery (usually 12 volts) and convert it to a high enough voltage (50,000 volts or more) to create a spark. 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. Weak ignition coil. The 12-volt pole is the spot where the power comes into your coil. Ford  |   Start your diagnostic from TEST 1, do not skip around from test to test unless instructed to do so by the TEST you are currently on. Note: Terminal 15 is positive, terminal 1 is negative. IMPORTANT: To get the most accurate test result from your ignition coil test you need to use a dedicated spark tester. Remove the ignition coil from the bracket or mounting block holding it in place. If the test described below tells you the ignition coil is bad, it's a simple matter to replace it with a new one by simply reversing the process by which you removed the old one. You can also conclude that it's not behind the dead cylinder's misfire problem. When a vehicle frequently stalls, misses or won't start at all, an ignition coil may need to be replaced. Your purchase helps support my work in bringing you real diagnostic testing information to help you solve the problem! Locate the coil on your vehicle. Although accessing and removing the ignition coil may vary from model to model, the process will be similar for all lawnmowers. If you test the coil and the meter remains at "1" it means there's no connectivity and that coil is faulty and needs to be replaced. He lives in Minneapolis, MN. Engine misses (misfires) as you accelerate it's under load. But before you do any test, it is important to take certain precautions. Remove the cowling (the outer housing) from around the engine, loosening whatever screws or bolts are holding it in place. Remove the spark plug wire from the spark plug. While there are other parts that can cause ignition problems, the following project will show how to test and replace a lawnmower ignition coil. Before condemning the ignition coil as defective you need to make sure that it's getting power and an activation signal. You can find this tutorial in Spanish here: Cómo Probar Las Bobinas De Encendido (2002-2005 4.2L Chevrolet TrailBlazer) (at: autotecnico-online.com). Without this spark the end result is a dead cylinder that is not producing power. How to Test Ignition Coils . Its function is to generate the electrical spark needed to ignite gasoline in the engine. Open the hood to locate the ignition coil. This component comes sealed, and is not a repairable item. Tools  |   Remove the ignition coil from its place on the valve cover. It converts the power from your car's 12-volt battery into the thousand or so volts that the spark plugs need in order to fire and then ignite the engine's air-fuel mixture. A gap that is too wide or too narrow will not allow the ignition system to work properly. With many lawnmowers, this will be enough to expose the flywheel and ignition coil; with other mowers, you may need to remove some other shields or parts before you see the coil. Testing the ignition coil and the spark plug Connect the tester between the spark plug boot and the spark plug. If you don't have one and need to buy one then I recommend the HEI spark tester. Jeep  |   In any gas-powered lawnmower engine, the _ignition coil_—called by some manufacturers the _ignition armature_—is a key element of the ignition system. If the test described below tells you the ignition coil is bad, it's a simple matter to replace it with a new one by simply reversing the process by which you removed the old one. He has been writing and editing books and articles on gardening, home improvement, woodworking, and home decor for more than 30 years. How to Test a Stihl Ignition Coil By Mary Lougee Hunker may earn compensation through affiliate links in this story. A safer way to test the ignition coil. Ground the spark tester with a battery jump start cable directly on the battery negative (-) terminal. Then the engine is cranked to see if the spark tester sparks. Zero resistance would indicate a shorted coil while a high resistance reading would indicate an open coil. This is a test result also confirms that this specific ignition coil is getting power and an activation signal from the fuel injection computer. 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. You will need to test the ignition coil if your vehicle does not start, misses frequently or stalls after warming up. Sparkplug. Most ignition coils should have a secondary resistance falling somewhere between 6,000 to 10,000 ohms; however, refer to manufacturer specifications for the correct range. Tighten down the armature tightly to the engine frame. It will be marked with a + sign, or it might only be indicated by a number. The ignition coil is usually hidden beneath the cover your lawnmower but is clearly visible when you take the motor cover off. Lay the ignition coil on a work surface. Turn your ignition switch to "on" and put a test light or meter on the coil, one lead to plus, the other to minus. Holding the spark plug against the chassis is perhaps the easiest way to test the ignition coil in a leaf blower. If the spark tester DOES NOT spark then you can conclude that the ignition coil is defective and behind the misfire problem (although it's a good idea to make sure it's getting power and an activation signal). The procedure involves using a digital multimeter (set to ohms) to check the resistance of the primary and secondary windings inside the coil. As you're already aware the ignition coil's job is to supply spark to its cylinder. Connect a spark tester to the ignition coil. Have a helper crank the engine while you observe the spark tester. Ignition System Wiring Diagram (2002-2005 4.2L Chevrolet TrailBlazer), How To Test The Ignition Coils (2002-2005 4.2L Chevrolet TrailBlazer), TAC System Wiring Diagram (2006-2007 4.2L Chevrolet TrailBlazer), “I bought a perfect second car... a tow truck.”Rodney Dangerfield, Home  |   By creating an account you agree to the Hunker. GM  |   TEST 1: Testing The Ignition Coil For Spark, TEST 2: Making Sure The Ignition Coil Is Getting Power, Cómo Probar Las Bobinas De Encendido (2002-2005 4.2L Chevrolet TrailBlazer). Smell of raw fuel coming out of the tailpipe. Either way, once the engine is started, the flywheel keeps turning, creating a self-perpetuated ignition cycle. To test the coil's secondary winding, attach the test probes to the outer 12-volt pole on the coil and the center pole (where the main wire goes to the distributor). You can choose to do one of these tests or both, just depends on your preferences. Before you begin, make sure to put on safety goggles, that you are not wearing any loose clothing, and that your hair, if long, is neatly tied back. Although manufactured to last, ignition coils … 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 engine idles fine but breaks up under load. 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. 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