To replace Toyota Supra ignition coils, let the engine cool, remove the engine cover, disconnect each coil connector, unbolt and pull the coil, then fit the new one and tighten it to the specification in the service manual. Coils and access differ by engine and model year, so use the manual. Related: Toyota Supra ignition system guide.
The Importance of Ignition Coils in Your Toyota Supra
Coils create the spark that ignites the fuel. A weak coil can cause misfires, rough running and a check engine light.
Tools Needed for Replacing Ignition Coils
- Socket set, ratchet and extension
- Torque wrench
- The correct new coil(s)
- Safety glasses and gloves
Safety Precautions Before You Start
Let the engine cool, disconnect the negative battery terminal if the manual says so, and wear gloves and eye protection.
How to Replace Toyota Supra Ignition Coils
- Remove the engine cover.
- Disconnect the connector of the coil you are replacing.
- Remove the bolt and pull the coil straight up.
- Check the spark plug well for oil or water.
- Fit the new coil, bolt it down to the specified torque, and reconnect the connector.
- Refit the cover.
Common Mistakes to Avoid During Ignition Coil Replacement
- Mixing up the connectors.
- Over-tightening the bolt.
- Dropping debris into the spark plug well.
- Ignoring a worn spark plug that caused the coil to fail.
Test Your New Ignition Coils
Start the engine, listen for a smooth idle, and check that no misfire code returns. Clear codes only after the repair.
Troubleshooting Common Issues With Ignition Coil Installation
If the misfire stays, check the connector, the spark plug and the injector for that cylinder.
Keep Your Ignition System Running Smoothly
Replace spark plugs on the interval in the owner’s manual, since worn plugs stress the coils.
Signs That Indicate Ignition Coil Failure
- Misfire or rough idle
- Flashing check engine light
- Loss of power
- Poor fuel economy
Related reading:
- How to Replace Spark Plugs In A Toyota Supra: Step-by-Step Guide
- How to Replace Toyota Supra Water Pump: Step-by-Step Guide
Frequently Asked Questions
Can I Replace the Ignition Coil Myself on a Toyota?
Many owners can, if the coil is easy to reach and they follow the manual. If it is not, use a shop.
How Do You Replace Ignition Coils?
Remove the cover, disconnect the connector, unbolt the coil, fit the new one and refit everything.
Do I Need to Disconnect the Battery When Changing Ignition Coils?
It is a good habit, and many manuals recommend it. Check yours.
What Are Signs of Bad Ignition Coils?
Misfires, rough idle, a flashing check engine light, and loss of power.
Conclusion
Follow the manual, replace worn plugs with the coils if due, and check for codes after the job.
