How to Test a Faulty Coil: A Step-by-Step Guide

Learn how to test if a coil is bad using a multimeter with our easy step-by-step instructions.

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Testing a coil involves a multimeter. First, disconnect the coil from power. Then, set the multimeter to ohms. For a cylinder coil pack, measure the primary resistance by touching the probes to the coil's primary terminals (should read 0.4 to 2 ohms). For the secondary resistance, measure between the high tension terminal and either primary terminal (should read 6,000 to 10,000 ohms). Any deviation from these ranges suggests a faulty coil needing replacement. Ensure all testing is done with power disconnected for safety.

FAQs & Answers

  1. What tools do I need to test a coil? You will need a multimeter to measure the resistance of the coil. Ensure you can set it to ohms for accurate readings.
  2. How do I know if my coil is bad? Test the coil's resistance using a multimeter. If the primary resistance is outside 0.4 to 2 ohms, or the secondary resistance is outside 6,000 to 10,000 ohms, the coil may need replacement.
  3. Is it safe to test a coil? Always ensure the power is disconnected before testing a coil to avoid electrical shock and damage to the multimeter.
  4. Can I test a coil without removing it? It's best to disconnect the coil for accurate testing. However, some multimeters allow for testing with the coil still connected, but it may not provide reliable results.