If your 2000 Honda Civic LX is experiencing symptoms like a flashing check engine light, engine misfires, hard starting, rough idle, poor acceleration, or reduced fuel economy, it may be time to replace the ignition coil. In this comprehensive guide, we’ll walk you through the process of diagnosing and replacing a faulty ignition coil on your Civic.
What is an Ignition Coil and How Does it Work?
An ignition coil is a critical component of your vehicle’s ignition system. It is essentially a transformer that takes the low voltage from the battery and amplifies it to the high voltage needed to create a spark at the spark plug. This spark ignites the air/fuel mixture in the engine cylinder, allowing the engine to run.
In the 2000 Honda Civic LX, there is one ignition coil for each cylinder. When the engine control module (ECM) sends a signal to the coil, it allows current to flow through the primary winding. When this current is abruptly cut off, it induces a high voltage in the secondary winding which is then sent to the spark plug via the coil’s output terminal.
Symptoms of a Failing Ignition Coil
When an ignition coil starts to fail, you may notice one or more of the following symptoms:
- Check Engine Light Flashing: The ECM detects misfires and triggers the check engine light to flash. Misfires can damage the catalytic converter if left unchecked.
- Engine Misfires: A failing coil can cause the corresponding cylinder to misfire, resulting in a rough running engine. Misfires are often most noticeable under load.
- Hard Starting: If the coil can’t provide sufficient spark, the engine may be difficult to start, especially when cold.
- Rough Idle: Misfires at idle can cause the engine to shake or vibrate more than usual.
- Poor Acceleration: Weak or inconsistent spark can lead to hesitation, stumbling, or a lack of power when accelerating.
- Reduced Fuel Economy: Misfires caused by a faulty coil can result in incomplete combustion, increasing fuel consumption.
It’s important to diagnose and address ignition coil issues promptly to prevent catalytic converter damage and restore reliable performance.
Safety Precautions Before Beginning Repair
Before starting any work on your ignition system, take these safety precautions:
- Disconnect the negative battery cable to prevent electrical shorts or shocks.
- Allow the engine to cool completely to avoid burns from hot components.
- Wear safety glasses to protect your eyes from debris or fluids.
- Put on gloves to keep your hands clean and prevent cuts or scrapes.
Tools, Parts, and Supplies
To replace the ignition coil on your 2000 Honda Civic LX, you’ll need the following:
Hand Tools
- Ratchet and socket set (8mm, 10mm)
- Screwdrivers (flathead and Phillips)
- Pliers (needle nose and regular)
Replacement Ignition Coil
For best results, use an OEM Honda ignition coil or a high-quality aftermarket equivalent. Cheap, generic coils may not last as long or perform as well. You can purchase a replacement coil from a Honda dealer, auto parts store, or online retailer. Make sure to select the correct part for your engine size (1.6L or 1.7L).
Supplies
- Dielectric grease to lubricate and protect the coil’s electrical connections
- Clean rags for wiping down surfaces
- Gloves to protect your hands
Diagnosing the Problem
Before replacing the ignition coil, it’s important to properly diagnose the issue to avoid unnecessary parts replacement.
Retrieving Diagnostic Trouble Codes
Use an OBD-II scan tool to check for diagnostic trouble codes (DTCs). Codes in the P0300-P0304 range indicate cylinder misfires, which could be caused by a failing ignition coil. However, misfires can also be caused by other issues like worn spark plugs, vacuum leaks, or fuel delivery problems.
Visual Inspection
Examine the suspected ignition coil for signs of damage:
- Cracks or carbon tracks on the coil casing
- Broken, bent, or corroded connector pins
- Oil or coolant contamination on the coil
If you see obvious damage, the coil likely needs to be replaced.
Testing Procedures
You can test the ignition coil with a multimeter:
- Disconnect the coil electrical connector and remove the coil from the engine.
- Set your multimeter to the ohms (Ω) setting.
- Measure the primary winding resistance between the positive (+) and negative (-) pins. Compare your reading to the manufacturer’s specifications, which are typically 0.7-1.0 ohms.
- Measure the secondary winding resistance between the positive (+) pin and the high voltage output terminal. This should be 12,000-14,000 ohms.
- If either reading is out of spec, the coil has failed and needs replacement.
Another diagnostic method is to swap the suspected coil with a known-good coil from another cylinder. If the misfire moves to the other cylinder, you’ve confirmed the coil is bad.
Ruling Out Other Potential Causes
Before condemning the ignition coil, check for other possible causes of misfires:
- Fouled or worn spark plugs
- Damaged spark plug wires (if equipped)
- Loose or corroded wiring connections
- Vacuum leaks
- Clogged fuel injectors
- Low fuel pressure
Address any other issues before replacing the coil to avoid a comeback.
Removing the Old Coil
Once you’ve confirmed the ignition coil is faulty, it’s time to replace it.
Disconnecting the Battery
First, disconnect the negative battery cable with a 10mm wrench or socket to prevent electrical shorts.
Locating the Ignition Coil
The ignition coils on the 2000 Honda Civic LX are mounted directly on the spark plugs, under the coil cover at the rear of the engine. The exact location varies slightly between the 1.6L and 1.7L engines:
- On the 1.6L, the coils are on the driver’s side of the engine
- On the 1.7L, the coils are in the center of the engine
Removing the Coil Cover
Remove the two 8mm bolts securing the plastic coil cover, then lift the cover off and set it aside.
Disconnecting the Electrical Connector
Unplug the electrical connector from the ignition coil. If it’s stuck, gently pry it off with a flathead screwdriver. Be careful not to damage the pins.
Removing the Mounting Bolt
Use a 10mm socket to remove the single bolt holding the ignition coil in place.
Pulling the Old Coil Out
Grasp the coil firmly and pull it straight out of the spark plug well. Don’t twist or bend it, as this can damage the spark plug or boot. If the coil is stuck, gently rock it side-to-side while pulling.
Installing the New Coil
Comparing New Coil to Old One
Before installing the new ignition coil, compare it to the old one to ensure they match. The new coil should have the same shape, size, and connector configuration.
Applying Dielectric Grease
Apply a thin layer of dielectric grease to the inside of the coil boot. This helps prevent voltage leaks and makes the boot easier to remove next time.
Inserting the New Coil
Push the new coil into the spark plug well until it is fully seated. Make sure the boot is securely attached to the spark plug terminal.
Replacing the Mounting Bolt
Thread the mounting bolt in by hand, then tighten it to 7-9 lb-ft (10-12 Nm) with a torque wrench. Don’t overtighten, as this can damage the coil or cylinder head.
Reconnecting the Electrical Connector
Plug the electrical connector back into the coil, making sure it clicks into place.
Reinstalling the Coil Cover
Place the coil cover back onto the engine and secure it with the two 8mm bolts.
Reconnecting the Battery
Reconnect the negative battery cable and tighten it with a 10mm wrench.
Verifying the Repair
After installing the new ignition coil, it’s important to verify that the repair was successful.
Clearing Diagnostic Trouble Codes
Use your OBD-II scan tool to clear any stored misfire codes. This will turn off the check engine light if no other issues are present.
Starting the Engine
Start the engine and let it idle. The engine should run smoothly without misfires. Rev the engine a few times to check for stumbling or hesitation.
Checking for Proper Operation
Take the vehicle for a test drive and verify:
- The engine idles smoothly without vibration
- There are no misfires under acceleration
- The engine has normal power and response
- The check engine light remains off
If you notice any remaining issues, there may be additional problems that need to be addressed.
Maintenance and Prevention
To keep your ignition system in top shape and prevent premature coil failure, follow these maintenance tips:
- Replace spark plugs at the manufacturer’s recommended intervals, typically every 30,000-100,000 miles.
- Inspect spark plug wires (if equipped) for cracks, burns, or loose connections. Replace as needed.
- Check and replace ignition coils every 100,000 miles or as needed.
- Keep the coils clean and dry. Oil or moisture can cause shorts and arcing.
Troubleshooting Common Problems
If you encounter issues after replacing the ignition coil, here are some common problems and potential solutions:
Engine Still Misfires
- Double check that the new coil is properly installed and connected.
- Ensure the spark plugs are in good condition and properly gapped.
- Check for other potential misfire causes like vacuum leaks or fuel delivery issues.
Check Engine Light Returns
- Use a scan tool to retrieve the trouble code. It may be unrelated to the ignition coil.
- Verify that the new coil is not defective.
- Check for wiring issues like shorts, opens, or poor connections.
When to Seek Professional Help
While ignition coil replacement is a relatively straightforward job, there are times when it’s best to seek the help of a professional mechanic:
- If you’re unsure of your diagnosis or don’t feel comfortable performing the repair yourself.
- If the vehicle has multiple, complex issues that require advanced diagnostic equipment.
- If you don’t have the necessary tools like a scan tool, multimeter, or torque wrench.
- If the vehicle is still under warranty and you don’t want to risk voiding coverage.
A qualified technician can accurately diagnose and repair your vehicle, ensuring reliable operation and peace of mind.
Conclusion
Replacing a faulty ignition coil on your 2000 Honda Civic LX can restore lost power, improve fuel economy, and eliminate annoying misfires. By following the steps outlined in this guide and using quality parts, you can successfully complete the job yourself and save money on labor costs.
Remember to always properly diagnose the problem before replacing parts, and address any other potential issues to prevent a comeback. With regular maintenance like spark plug replacement and coil inspection, you can keep your Civic’s ignition system running strong for years to come.
Frequently Asked Questions
Q: What does an ignition coil do?
A: The ignition coil transforms the low battery voltage into the high voltage needed to create a spark at the spark plug, igniting the air/fuel mixture in the engine.
Q: Where is the ignition coil located on a 2000 Honda Civic LX?
A: The ignition coils are mounted directly on the spark plugs at the rear of the engine, under the coil cover. On the 1.6L engine they are on the driver’s side, while on the 1.7L they are in the center.
Q: Can I drive with a bad ignition coil?
A: It’s not recommended, as a failing coil can cause misfires, poor performance, and reduced fuel economy. Driving with a misfire can also damage the catalytic converter over time.
Q: How often should ignition coils be replaced?
A: Ignition coils are typically replaced every 100,000 miles or as needed. If one coil fails, it’s often advisable to replace all of them as a preventative measure.
Q: Are aftermarket coils as good as OEM Honda ones?
A: High-quality aftermarket coils can work just as well as OEM parts. However, be cautious of cheap, generic coils as they may not last as long or perform as reliably. Stick with reputable brands or OEM for best results.
Q: Can a bad ignition coil cause catalytic converter damage?
A: Yes, if left unaddressed, misfires caused by a failing coil can allow unburned fuel to enter the exhaust and damage the catalytic converter over time.
Q: How do I know if my ignition coil is bad?
A: Common symptoms of a failing coil include a flashing check engine light, engine misfires, hard starting, rough idle, poor acceleration, and reduced fuel economy. A scan tool can confirm cylinder misfire codes.
Q: What is the average cost to replace an ignition coil?
A: The cost varies depending on the vehicle and labor rates, but you can typically expect to pay between $50-$150 for a single coil, plus an additional $50-$100 for labor if you have it professionally installed.
Q: Can I replace just one coil or should I do them all?
A: While you can replace just the faulty coil, it’s often recommended to replace all of them at the same time. This is because if one coil has failed, the others may be nearing the end of their service life as well.
Q: What else can cause similar symptoms as a bad coil?
A: Other potential causes of misfires and poor performance include worn spark plugs, damaged plug wires, vacuum leaks, clogged fuel injectors, and low compression. Always perform a thorough diagnosis to identify the root cause.