Replacing Cap, Rotor and Spark Plug Wires

Removing and Installing Distributor Cap, Rotor, and Spark Plug Wires
These components direct high voltage to the spark plugs, and proper engine performance depends on getting the best possible spark. Poor spark due to worn and corroded contacts or failed insulation which allows the spark to short to ground are the primary reasons to replace these components.

Replacing Spark Plug Wires
Each spark plug wire leads from a specific terminal on the distributor cap to a specific spark plug. When removing the wires label their positions, if necessary, so that they can be correctly reinstalled.

The spark plug wires are removed by pulling the boots straight away from the distributor cap or spark plugs. Pull only on the connector, not on the wire. For old wires, twisting the connector first or peeling back the rubber boot may aid removal.

CAUTION: Wiggling the connectors from side to side when removing the spark plug wires from the distributor cap may damage the cap.

Replacing Distributor Cap and Rotor
The distributor cap is held in place with two spring clips which can be released using the blade of a screwdriver. Avoid bending the clips. To replace the cap remove the wires, then release the spring clips and remove the suppression shield.

On all except 16-valve engines, simply pull the rotor off the shaft. When installing a new rotor, make sure that the key inside the rotor fits into the notch on the distributor shaft.

On l6valve engines, the rotor is more permanently attached to the shaft. To remove it, the lower part must be carefully crushed using a pair of pliers. Clean off all of the old adhesive. To install a new rotor, use an instant adhesive such as Loctite 325 Speed Bonder. Make sure that the key inside the rotor fits into the notch on the distributor shaft.

CAUTION: Do not hit the rotor or distributor shaft with any tool.

Spark plug wires must be installed so that the spark plugs have the proper firing order. The firing order is 1-3-4-2. Cylinder no.1 is on the passenger side, closest to the camshaft drive belt.

To find the no.1 terminal on the distributor cap, remove the cap and find the no.1 cylinder TDC mark on the edge of the distributor housing. See Fig. 5-4. The distributor cap terminal closest to this mark (with the cap installed) is the terminal for the no.1 cylinder.

On all except 16 valve engines, the wires connect to the distributor cap terminals according to the firing order (1-3-4-2), in clockwise direction from no.1.

On 16 valve engines, the wires connect to the distributor cap terminals according to the firing order (1-3-4-2), in counterclockwise direction from no.1.

Fig. 5-4:

Fig. 5-4. Distributor rotor aligned with No 1 cylinder TDC mark (arrow) on distributor housing.