Ignition systems have changed dramatically since these vehicles were first introduced. Most vehicles today use coil packs instead of distributors. They have no need of distributor caps or rotors. Camshaft and crankshaft sensors have replaced these items. For the most part, timing is no longer adjustable, but is being controlled by the PCM (Powertrain Control Model). However, in the interest of those vehicles that operate with a distributor cap and rotor, some basic information will be given.
A physical inspection of the distributor cap and rotor should be done at the same time as the plug wires are being checked. When inspecting the distributor cap, check for obvious signs of damage, such as a broken tower, crack in the body of the cap, or external carbon tracks . When checking on the inside of the cap, use a bright light to illuminate the inner surface. Check for charred or eroded terminals, inspect for carbon tracks that go from terminal to terminal or run to the bottom of the cap. Look for a worn or damaged rotor button (center electrode). Also, take a close look at the inside terminals for metal to metal contact. Damaged or cut terminals could mean a rotor or cap that was not properly installed; or it could mean that the distributor housing has worn beyond its limits and the shaft is wobbling when it rotates, or that the distributor shaft is bent.
Removal & Installation
- Disconnect the negative battery cable.
- Remove the rubber cap cover (if equipped), from the distributor cap.
- Remove the secondary wiring (spark plug wires) if a new cap is being installed.
- On the 3.8L engine, remove the two retaining screws in the cap to disengage it from the distributor housing.
- On the 5.0L engine, unsnap the retaining clips holding the cap to the distributor housing.
- Remove the cap, this exposes the ignition rotor.
- Note the position of the rotor before removal.
- To install the rotor, align it to the distributor shaft.
- Seat the distributor cap onto the distributor housing, making sure to align the cap properly.
- Install the cap screws carefully to hold the cap in place; or snap the retaining clips onto the distributor cap.
- Install the negative battery cable.