Spark plug wires are usually replaced in sets. If a wire is found faulty, it is recommended to replace all of them and not just the one or two that are bad.
At every tune-up/inspection, visually check the spark plug cables for burns cuts, or breaks in the insulation. Check the boots and the nipples on the distributor cap and/or coil. Replace any damaged wiring.
Every 50,000 miles (80,000 Km) or 60 months, the resistance of the wires should be checked with an ohmmeter. Wires with excessive resistance will cause misfiring, and may make the engine difficult to start in damp weather.
To check resistance, on the 4 cylinder engines, remove the distributor cap, leaving the wires attached. Connect one lead of an ohmmeter to an electrode within the cap; connect the other lead to the corresponding spark plug terminal (remove it from the plug for this test). Replace any wire which shows a resistance of over 25,000 ohms. Test the high tension lead from the coil by connecting the ohmmeter between the center contact in the distributor cap and either of the primary terminals of the coil. If resistance is more than 25,000 ohms, remove the cable from the coil and check the resistance of the cable alone. Anything over 15,000 ohms is cause for replacement.
To check the resistance on the V6 engines, remove the V-bank cover and then disconnect the wire at the plug. Trace the wire back to the distributor cap, pry up the lock claw and disconnect the holder from the cap and then disconnect the wire at the grommet. Connect one lead of an ohmmeter to each end of the spark plug wire. Replace any wire which shows resistance over 25,000 ohms. Test the high tension lead from the coil by connecting the ohmmeter between the center contact in the distributor cap and either of the primary terminals of the coil. If the resistance is more than 25,000 ohms, remove the cable from the coil and check the resistance of the able alone. Anything over 15,000 ohms is cause for replacement.
It should remembered that resistance is also a function of length; longer the cable, the greater the resistance. Thus, if the cause on your car are longer than the factory originally, resistance will be higher, quite possibly outside these limits.REMOVAL & INSTALLATION
- Disconnect the negative battery cable.
- Label and disconnect the wires from each spark plug one at a time.
- Remove the spark plug wires from the distributor cap. On some models you may need to use a flat bladed tool to lift up the lock claw and disconnect the holder from the cap.
- Separate the wires at the grommet.
- Pull the plug wires from the retaining clamps.
- Attach the holder and grommet portion to the distributor cap. Make sure that the holder is installed correctly to the grommet and cap.
- Check that the lock claw of the holder is engaged by lightly pulling on the holder.
- On the center cord, insert the grommet and holder together.
- Secure the wires with the clamps.