- Toyota Cars & Trucks question i found out that it might be a faulty coil on plug for cel sometime light on and rough idle. Here we use a spark plug coil as an example. To locate the primary and secondary terminals, consult your vehicle repair manual, if necessary. The Power and Ground Circuits of the Coil-On-Plug ignition coil (type with three wires in the connector) have to be tested to find out the real reason you got a No spark result on your spark tester. It is advised to test the coil when the coil is hot. Testing a coil-on-plug (COP) type ignition coil is similar to testing other ignition coils. 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. While the first method is a basic go or no-go test, it does not indicate the condition of the coil, whereas the second test does. Here are the step by step tests for testing the majority of the Coil-On-Plug ignition systems that have ignition coils with three wires (circuits) in the connector. And it's just that the Coil-On-Plug ignition coil is bad. Repair the open-circuit problem and retest for spark or retry starting the vehicle. When testing ignition coils, it is possible to have some spark; however, the spark may not be sufficient to fire the spark plugs under compression conditions. share | improve this question | follow | edited Mar 8 '16 at 23:38. Suzuki  |   When testing the condition of the secondary winding, the terminals of the multimeter should be placed on one of the outer posts as well as the center post where the coil wire attaches. You can probe the front of the female terminals of the connector or (like what I do) use a wire-piercing probe to test the wire itself (like in the photo above). Left, (on the analog meter) simply read IAT Sensor Wire Insulation Problem And Wires Shorted Together, How To Bench Test A Ford Relay (Large Relay), "I always take life with a grain of salt, ...plus a slice of lemon, ...and a shot of tequila. You can test a 12-volt ignition coil for effectiveness by checking the resistance of its wire windings with a multimeter. Faulty coils can often test fine when cool, ... Set the multimeter to read ohms and test the resistance in the primary and secondary sides of the coil. Step 5: involves testing your secondary circuit of the ignition coil. Step 2: Test the resistance. Here are the steps to follow to check the ignition coil: Testing your ignition coil by using a multimeter After you have ensured the spark plug is not an issue, it’s time to check on the ignition coil. The car has ECU controlled timing / ignition and there are two coils, each one servicing two cylinders I assume. The secondary winding takes the electrical charge from the coil to the distributor or to the spark plug. Leave a Reply Cancel reply. That method will only tell if there is something seriously wrong with the coil (aka if it's dead). Complete testing of a coil often involves resistance testing of its windings but also a test of of the insulation of the coil wires. Honda  |   The procedure involves using a digital multimeter (set to ohms) to check the resistance of the primary and secondary windings inside the coil. Red goes to the positive side of the battery, Black goes to the negative side. And only the result of this spark tester can be trusted. 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. This checks the secondary resistance. An assistant then cranks up the engine. To test continuity, all you have to do is stick 2 terminals on your multimeter against 2 ends of an electrical current. I recommend the following article to learn more about carbon tracks Ignition Misfire a Case Study of a Dodge Neon. The other is without one and requires that you swap the some COP coils to find out. Even if you find a bad coil, simply replacing it is not the whole repair, because like so many other parts of a vehicle, COP ignition coils don’t really die, they’re murdered. Measuring ignition coil resistance was once a popular test method. Step 2: Test the resistance. Next, remove the caps or connectors to the glow plugs and connect the negative multimeter lead to a ground point in the engine. The most common method used by backyard mechanics involves shorting a spark plug to the engine or chassis and cranking the engine over. Jeep  |   The most likely cause will be an open-circuit problem in that ignition coil's Power Circuit. Add comment. Once this is done, open up the hood and disconnect negative cables from the battery. Then start the engine and watch the tester window. Replacing the ignition coil with a new one will only be a waste of time and money since, without Power the new one will not spark. After replacing the blown fuse or the defective relay. If there is spark, the coil is good. Do NOT follow this link or you will be banned from the site! Step 2 . The Coil-On-Plug ignition coil to be tested is removed from its place and tester is attached to it. A spark plug … Jumpering to Ground just one Coil-On-Plug ignition coil should provide Ground to all of them (consult your repair manual's Wiring Diagrams to be sure). Test for Power (12 Volts) and Ground second. ", Home  |   Step 5: Test the secondary circuit of the ignition coil. Continuity refers to how much resistance there is in a closed electrical current. This material may not be reproduced without the author's consent. Safety is the number one priority when testing for faulty coils with a multimeter. So whether it's a Ford, a Chevrolet, a Mazda, a Suzuki, a Mitsubishi or whatever in the USA, or Europe or South or Central America, or where ever on the planet, these easy tests work. A weak or damaged ignition coil can cause engine misfires, stalling, and lower fuel economy. The normal, acceptable range for a standard 12-volt car is 1.5 to 1.7 Ohms. Usually these circuits are fine and are providing their respective signals. The cool thing about testing the Power and Ground Circuits is that it doesn't require a lot of time nor are the tests difficult to do. Here are the possible results: The Ground Circuit is tested with the Key On or Off. Volt meter leads on trigger and power wire . In this video learn how to check resistance using a multimeter. 1. By testing for the presence of these signals we can be absolutely certain that we're gonna' spend the money on a solution and not a guess. Ign coil secondary resistance 6,000 - 9,000 ohms . Attach the ends of a multimeter to the coil connections for input and to ground, testing electrical resistance in the unit. DucatiKiller. Plug wire and plug are good. You'll also know for sure if what you have is a bad coil or if you need to spend money on further troubleshooting. Chrysler  |   secondary winding resistance is the plug leads test there should be 20-30K for spec. Watch for a spark in the tester window as you pull the starter cord. Any variation at all from the recommended reading is a sign that the coil should be replaced. Replace the coil unit with a new one, if the reading shows as infinity or zero. Then, attach the negative probe to the negative … I don't recommend using just any type of spark tester. Unless you are a professional electrician, a multimeter can be a confusing instrument to use with all the buttons, numbers and symbols. 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