See Figures 1 and 2
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, an ohmmeter should be used on each wire to test resistance between the end connectors. Remove and install/replace the wires in order, one-by-one.
Resistance on these wires must not exceed 7,000 ohms per foot. To properly measure this, remove the wires from the plugs, coil, or the distributor cap. Do not pierce any ignition wire for any reason. Measure only from the two ends.
Whenever the high tension wires are removed from the plugs, coil, or distributor, silicone grease must be applied to the boot before reconnection. Coat the entire interior surface with Ford silicone grease D7AZ-19A331-A or its equivalent.
REMOVAL & INSTALLATION
See Figure 3
When you're removing spark plug wires, work on one at a time. Don't start by removing the plug wires all at once, because, unless you number them, they may become mixed up. Take a minute before you begin and number the wires with tape.
- Disconnect the negative battery cable, and if the vehicle has been run recently, allow the engine to thoroughly cool.
- Carefully twist the spark plug wire boot to loosen it, then pull upward and remove the boot from the plug. Be sure to pull on the boot and not on the wire, otherwise the connector located inside the boot may become separated.
- Carefully twist the spark plug wire boot to loosen it, then pull upward and remove the boot from the distributor towers or coil tower. Be sure to pull on the boot and not on the wire, otherwise the connector located inside the boot may become separated.
- Apply a small amount of silicone dielectric compound to the end of the spark plug lead or inside the spark plug boot to prevent sticking, then install the boot to the spark plug and push until it clicks into place. The click may be felt or heard, then gently pull back on the boot to assure proper contact.
- Push the boot onto the distributor tower or coil tower until it is firmly engaged.