There are two kinds of test available to test your ignition coil, and they are, spark plug test and bench test. Although the following explanation is not theory heavy or full of big technical words/terms, it will help you to see how the ignition coil works. The ignition system has two wires attached to the switch’s run terminal. Make note of the reading on the ohmmeter. If you're looking for the resistance test of the primary and secondary circuits, this article will not help you (in my opinion, the primary/secondary resistance test is a complete waste of time and life that does not work around 99% of the time to diagnose a bad ignition coil). 2. Open your hood and unplug all four wire pin connectors on the coil pack. Measuring ignition coil resistance was once a popular test method. The secondaryof the coil is the area/towers where the spark plug wires plugin. It's something that you can do without removing these parts (to replace them and see which one solves the no spark-no start problem) and in this tutorial I'll show you how. 4. Check the primary windings for continuity and resistance. All Rights Reserved. These are usually located right on the engine, either bolted directly to the spark plugs or mounted remotely somewhere on top of the engine. Connect the meter between the or CB terminal of the coil and earth, and switch on the ignition. Your purchase helps support my work in bringing you real diagnostic testing information to help you solve the problem! Enclosed units will have a diagram pointing out the primary studs. Operation and testing coil over plug ignition (4 wire) - Toyota/Lexus Print This case study is perfect for anyone interested in the working details of Toyota/Lexus coil over plug ignition system, and the very similar three-wire designs used by many other manufacturers. Other components can fail and provoke a no start. Disconnect a spark wire from a spark plug (or the coil wire from the distributor cap). Use a flashlight or an area with good lighting to perform a visual inspection of the spark plug wires and the cap on top of them, called the boot. Some older mechanics tend to use the method that involves disconnecting the spark plug wire and holding it against a metal chassis while cracking the engine. The profile ignition pickup (PIP) sensor, which is what Ford calls the crank sensor, gets power from the ICM and as the engine cranks it starts to generate a crankshaft position signal (called the PIP signal). Step 3: Disconnect the wiring harness for the ignition coils. GM  |   It should be within the range indicated in your service manual. The procedure involves using a digital multimeter (set to ohms) to check the resistance of the primary and secondary windings inside the coil. Remove the large wire from the center of the coil by pulling it straight out of the coil. How? However, you should have some experience working with car engines before attempting to deal with a coil wire. Chrysler  |   Knowing a little practical working theory will answer a lot of questions that the article doesn't answer. But before you do any test, it is important to take certain precautions. Connect the ohmmeter to the secondary winding. Connect your ohmmeter or multimeter to the primary studs of the coil. 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. Jeep  |   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. This PIP signal is then sent to and received by the ignition control module (ICM). Remove all wires connected to the coil, then unbolt it from the engine. Hold this HT wire near a grounding point (or near the connector end of a spark plug), and position the tip of a graphite pencil in between. Testing the coil wire is an excellent way to avoid problems down the road. Check the ignition coil for mechanical damage; Check the housing for hairline cracks and sealant leaks. One goes into the module and the other establishes a connection to the primary resistor and coil. 3. One can further analyze the results by using machines that can test the coils under pressure. TEST 3: Testing For Spark Directly On The Ignition Coil. Turn off the engine and ensure the ignition is off. Live. If the ignition coil has a ground wire, also loosen and remove this at the point it attaches to the lawnmower chassis. Ignition Coil Test -No Spark No Start Tests (Ford 4.9L, 5.0L, 5.8L), IGNITION COIL TEST 1: Testing For Spark With A Spark Tester, IGNITION COIL TEST 2: Testing For Spark Directly On Coil's Tower, IGNITION COIL TEST 3: Verifying Ignition Coil Is Getting 12 Volts, IGNITION COIL TEST 4: Verifying The Switching Signal With A Test Light, Cómo Probar La Bobina De Encendido (Ford 4.9L, 5.0L, 5.8L). Tools  |   Once the ignition coil gets this switching signal, it starts to spark away and as you're already aware, this spark gets delivered to the center of the distributor cap by a high tension wire. The coil consists of two windings of wire, the primary and the secondary. First measure the resistance between the primary wire that comes from the CDI box and the ground or ground wire. What Tools Do I Need To Test The Ignition System? It’s important to keep an eye on your spark plug wires to avoid subsequent engine issues. Testing the coil can be done with a multimeter and basic mechanical skill. With the introduction of coil-on-plug ignition, there is no long wire that is needed to connect a coil to the spark plug.. On engines that are equipped with a distributor or a remote coil pack, spark plug wires are used to transfer the spark from the coil to the spark plug. You won't need any expensive testing equipment to follow the simple step-by-step testing instructions presented here. It will be marked with a + sign, or it might only be indicated by a number. Turn the vehicle off and open the hood. TEST 2: Testing For Spark Directly On The Distributor Cap. It all starts when you turn the key and start cranking the engine and in a nutshell, this is what happens: In the next page we'll jump right into the first ignition coil test. After finishing all these processes, ensure to reconnect your vehicle’s electrical connectors and … The process of testing the ignition coil of a leaf blower. The dwell period on an engine with electronic ignition is controlled by the current-limiting circuit in the amplifier or ECM. This will serve as a ground. You can choose to do one of these tests or both, just depends on your preferences. Check the electrical wiring and plug connections for damage and oxidation. Look for physical damage to the wires or boots, such as cuts and scorch marks. Hold the spark plug with insulated pliers and insert it into the coil wire. Bench Test (Coil Wire is Uninstalled) Step 1 Connect your ohmmeter or multimeter to the primary studs of the coil. Remove one spark plug using a spark plug socket. Do not lean on the fender or against the frame of your car when performing a bench test. The function of this component is to provide voltage to the ignition control module and ignition coil. Crack the engine and check for a good spark at the spark tester. Step 2: Locate the ignition coil, or coils, on your vehicle. Disclaimer. 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. The test you'll be doing is an on car test done with the ignition coil in action. 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997. The testing of these two circuits is done in part while the engine is being cranked. While testing your ignition coils, it’s a good idea to inspect the spark plugs and wires, too. As with most types of vehicular maintenance, you'll want to begin the test with the vehicle in park and with the engine off. 1995 Ford F150-F350 PCM Pin Out Chart (4.9L California Only), 1994-1995 Ford F150-F350 PCM Pin Out Chart (4.9L Only), 1992-1993 F150-F350 Fuel Pump Circuit Tests (Ford 4.9L, 5.0L, 5.8L), “When I was born I was so ugly the doctor slapped my mother.”Rodney Dangerfield, Home  |   This material may not be reproduced without the author’s consent. Have a second person start the car. From this point, the distributor rotor distributes the spark to the cylinders across the spark plug wires. You'll need a spark tester, a multimeter, a 12 volt test light, and a helper (to assist you in cranking the engine). Step 4 Place the test leads from the ohmmeter on the side terminals, one on each side. Note. Do NOT follow this link or you will be banned from the site! Some 4-wire COPs have two ground pins and no feedback signal, these should be tested as a 3-wire COP please see 3-Wire COP Test. First, be sure to have the ignition turned off and the coil disconnected from the ignition. If you receive a nice, bright spark, your coil is fine. Start your diagnostic from TEST 1, do not skip around from test to test unless instructed to … Do not use a regular spark plug instead of a spark tester to test for spark. 5. If necessary, remove any plastic covers that may be covering the ignition coils. By this time, the fuel injection computer is also injecting fuel into the engine, which the spark will ignite, thus the engine starts! The ignition control module (ICM) and the ignition coil get power (12 Volts). Step 5: Test the secondary circuit of the ignition coil. Make sure you hold the plastic portion of the screwdriver. The ignition control module (ICM) and the ignition coil get power (12 Volts). Writing since 1999, Darla Ferrara is an award-winning author who specializes in health, diet, fitness and computer technology. Historically, the supply voltage was present as soon as the ignition … The time between these points is called either the dwell period or the coil's saturation time. If your plug wires and caps check out, you can now test your ignition coil. Your helper should stay outside the vehicle and away from the ignition switch before and after you set up the test. A faulty coil wire will keep your car from starting when you need it. 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