Testing the ignition coils in your Performance Japanese car can be done using a few different methods. Here’s a step-by-step guide to help you through the process based on testing Nissan coils:
Tools and Materials Needed:
- Multimeter (with Ohm measurement capability)
- Spark tester (optional but recommended for a more comprehensive test)
- Basic hand tools (e.g., screwdrivers, socket set)
Steps to Test Ignition Coils:
- Safety First:
- Ensure the car is off and the keys are removed from the ignition.
- Disconnect the negative terminal of the battery to avoid any electrical shorts or shocks.
- Locate the Ignition Coils:
- The ignition coils are usually located on top of the engine, connected to the spark plugs. For the Skyline BNR32 GTR, they are likely under a coil cover.
- Remove the Ignition Coils:
- Carefully disconnect the wiring harness from each ignition coil.
- Use the appropriate tools to remove the bolts securing the coils in place. Gently pull the coils out.
- Visual Inspection:
- Check each coil for signs of damage, such as cracks, corrosion, or burn marks. Any visible damage usually means the coil needs to be replaced.
- Resistance Test with a Multimeter:
- Primary Coil Resistance:
- Set your multimeter to the Ohms (?) setting.
- Place the positive (red) probe on the positive terminal of the coil and the negative (black) probe on the negative terminal.
- Compare the reading to the manufacturer’s specifications (typically found in the service manual). A significant deviation means the coil might be faulty.
- Secondary Coil Resistance:
- Place one probe on the positive terminal and the other on the high-tension terminal (where the spark plug connects).
- Again, compare the reading to the specifications.
- Primary Coil Resistance:
- Spark Test (Optional but Recommended):
- Reconnect the ignition coil to the wiring harness but leave the coil out of the engine.
- Attach a spark tester to the ignition coil output (where it connects to the spark plug).
- Ground the spark tester to the engine block.
- Crank the engine and observe the spark tester. A strong, consistent spark indicates the coil is functioning properly. A weak or no spark suggests the coil may be faulty.
- Reinstall the Coils:
- If the coils pass the tests, reinstall them in the reverse order of removal.
- Reconnect the battery.
Additional Tips:
- Swap Test: If you’re unsure about a coil’s condition and have a similar working coil, swap them and see if the misfire moves to a different cylinder.
- Code Reader: Using an OBD-II scanner can help identify which cylinder is misfiring, allowing you to focus on specific coils.
- Service Manual: Always refer to the vehicle’s service manual for specific resistance values and testing procedures.
If you find any ignition coil that fails the resistance test or does not produce a proper spark, it should be replaced. Ignition coils are critical components, and ensuring they are in good working condition is essential for optimal engine performance.