See Figures 1 and 2Primary and Secondary Circuit Test
- Turn the ignition switch OFF , disconnect the battery, then detach the wiring harness connector from the ignition coil to be tested.
- Check for dirt, corrosion or damage on the terminals.
- Use an ohmmeter to measure the resistance between the following terminals on the ignition coil, and note the readings:
The resistance between all of these terminals should have been 0.3-1.0 ohms. If the resistance was more or less than this value, the coil should be replaced with a new one.
- Measure, using the ohmmeter, and note the resistance between each corresponding coil terminal and the two spark plug wire towers on the ignition coil. The coil terminals and plug wires towers are grouped as follows:
4.6L engines-right-hand coil pack
4.6L engines-left-hand coil pack
If the resistance for all of the readings was between 6,500-11,500 ohms, the ignition coils are OK. If any of the readings was less than 6,500 ohms or more than 11,500 ohms, replace the corresponding coil pack.
On 4.6L engines, if one coil pack is found to be defective, the other pack does not need to be replaced.
REMOVAL & INSTALLATION
See Figures 3 through 15
The 3.8L engine utilizes one coil pack containing three separate coils, and the 4.6L engines use two coil packs containing two separate coils each.
- Disconnect the negative battery cable.
- Unplug the electrical harness connector from the ignition coil pack.
- Label and remove the spark plug wires from the ignition coil terminal towers by squeezing the locking tabs to release the coil boot retainers.
- Remove the coil pack mounting screws and remove the coil pack.
- Install the coil pack and the retaining screws. Tighten the retaining screws to 40-62 inch lbs. (4.5-7 Nm).
Be sure to place some dielectric compound into each spark plug boot prior to installation of the spark plug wire.
- Attach the spark plug wires and electrical harness connector to the coil pack.
- Connect the negative battery cable.