Unleash the Power: Essential Tips for How to Test LS Ignition Coil Successfully!

If your LS-powered vehicle is experiencing misfires, rough idling, or a lack of power, a faulty ignition coil could be the culprit. Knowing how to test LS ignition coils is a valuable skill for any DIY mechanic. This guide will walk you through the process, equipping you with the knowledge and tools to diagnose and potentially resolve this common issue.

Understanding the Ignition Coil’s Role

The ignition coil is a crucial component in your LS engine’s firing system. Its primary function is to transform low-voltage battery power into a high-voltage spark that ignites the air-fuel mixture in the combustion chamber. This spark initiates the combustion process, driving the pistons and powering your engine.

Recognizing the Symptoms of a Faulty Ignition Coil

Before diving into the testing process, it’s essential to identify the signs that might indicate a problem with your ignition coil:

• Misfires: The most common symptom is a misfire, which can manifest as a rough idle, a sputtering engine, or a loss of power.
• Engine Stalling: In severe cases, a faulty coil can lead to engine stalling, especially at idle.
• Check Engine Light: The “Check Engine” light will typically illuminate on your dashboard, accompanied by a diagnostic trouble code (DTC) related to a misfire.
• Backfiring: An occasional backfire through the exhaust system can also be a sign of a faulty coil.

Gathering the Necessary Tools

To test your LS ignition coil, you’ll need a few basic tools:

• Multimeter: A digital multimeter is essential for measuring voltage and resistance.
• Spark Plug Socket: This specialized socket is designed to remove and install spark plugs safely.
• Spark Plug Wrench: You’ll need a wrench that fits your spark plug socket to tighten and loosen the spark plugs.
• Wire Brush: A wire brush is helpful for cleaning the spark plug terminals and the ignition coil connectors.
• Safety Glasses: Always wear safety glasses to protect your eyes from potential debris.

The Visual Inspection: A Quick Check

Before moving on to electrical testing, perform a visual inspection of the ignition coil. Look for any:

• Cracks or Damage: Check the coil housing for any cracks, chips, or other signs of physical damage.
• Corrosion: Inspect the coil terminals and connectors for corrosion or buildup.
• Loose Connections: Ensure that all connections to the coil are secure and not loose.

Testing the Ignition Coil: Resistance Check

The first step in testing the ignition coil is to measure its resistance. This test helps determine if the coil’s internal windings are intact.

1. Disconnect the Coil: Disconnect the ignition coil from the spark plug and the engine wiring harness.
2. Locate the Terminals: Most LS ignition coils have two terminals: one for the primary winding and one for the secondary winding.
3. Measure Resistance: Using your multimeter set to the “Ohms” setting, measure the resistance between the primary and secondary terminals.

• Primary Winding: The resistance should be between 0.5 and 2 ohms.
• Secondary Winding: The resistance should be between 8,000 and 15,000 ohms.

4. Compare to Specifications: Compare your readings to the manufacturer’s specifications for your specific coil. If the resistance readings are outside the specified range, the coil is likely faulty.

Testing the Ignition Coil: Spark Test

The spark test is another crucial step in diagnosing a faulty ignition coil. It allows you to visually verify if the coil is producing a strong spark.

1. Remove the Spark Plug: Remove the spark plug from the cylinder associated with the ignition coil you’re testing.
2. Connect the Spark Plug Wire: Connect the spark plug wire to the spark plug.
3. Ground the Spark Plug: Hold the spark plug against a grounded metal surface, such as the engine block.
4. Turn the Engine Over: Have someone crank the engine while you observe the spark plug.
5. Inspect the Spark: A healthy spark should be bright blue and consistent. If the spark is weak, intermittent, or absent, the ignition coil is likely faulty.

Testing the Ignition Coil: Voltage Check

The final step in testing the ignition coil is to check the voltage supplied to the coil. This test helps determine if the coil is receiving the necessary power to function properly.

1. Connect the Multimeter: Connect your multimeter to the positive (+) and negative (-) terminals of the ignition coil connector.
2. Set the Multimeter: Set your multimeter to the “DC Voltage” setting.
3. Turn the Engine On: Have someone turn the engine on while you observe the voltage reading.
4. Check the Voltage: The voltage reading should be between 10 and 14 volts. If the voltage is significantly lower than this range, there might be a problem with the wiring or the battery.

Troubleshooting and Replacing a Faulty Ignition Coil

Once you’ve confirmed that the ignition coil is faulty, it’s time to replace it. Here’s a brief guide:

1. Disconnect the Battery: Disconnect the negative (-) terminal of the battery to prevent electrical shock.
2. Remove the Faulty Coil: Disconnect the spark plug wire, the ignition coil connector, and any other connections. Remove the coil from its mounting location.
3. Install the New Coil: Install the new ignition coil in the same location as the old one. Ensure that all connections are secure.
4. Reconnect the Battery: Reconnect the negative (-) terminal of the battery.
5. Clear the Check Engine Light: After replacing the coil, clear the check engine light by using an OBD-II scanner.

Final Thoughts: Your LS Engine’s Spark Whisperer

Mastering the art of testing LS ignition coils empowers you to troubleshoot engine misfires and keep your LS-powered vehicle running smoothly. By following this guide and understanding the role of the ignition coil, you’ll be equipped to diagnose and address this common issue, saving time and money in the process.

Information You Need to Know

Q: What is the difference between an ignition coil and an ignition module?

A: An ignition coil is a single component that creates a high-voltage spark for one spark plug. An ignition module is a control unit that houses multiple ignition coils for a multi-cylinder engine.

Q: How long do LS ignition coils typically last?

A: The lifespan of an ignition coil varies depending on factors like driving conditions, maintenance, and quality. However, they typically last between 50,000 and 100,000 miles.

Q: Can a bad spark plug cause a faulty ignition coil?

A: While a bad spark plug can lead to misfires, it’s unlikely to directly cause an ignition coil to fail. However, a faulty spark plug can put extra stress on the coil, potentially shortening its lifespan.

Q: Can I test the ignition coil with the engine running?

A: It’s not recommended to test the ignition coil with the engine running. Doing so can expose you to high voltage and potentially cause damage to the coil or other components.

Q: How do I know which ignition coil is bad if multiple cylinders are misfiring?

A: You can use a cylinder identification tool or a diagnostic scanner to pinpoint the specific cylinder(s) misfiring. Then, test the ignition coil associated with that cylinder.