The engine coil, sometimes referred to as the ignition coil, operates to direct a strong electrical current to the distributor, which then sends the current to each of the spark plugs through the spark plug wires. A defective ignition coil is most commonly associated with engine misfiring and starting difficulties. Ignition coils are sealed units, and therefore they cannot be repaired. However, the task of replacing the coil is fairly straightforward.
Locate the coil by tracing the spark plug wire in the center of the distributor cap from the distributor to the coil.
Grasp the rubber boot at the tip of the coil end of the distributor's spark plug wire. Pull the wire off of the coil. Take care not to pull the actual wire, which could damage it.
Wrap each wire attached to the sides of the coil with a piece of masking tape. Write the location of each wire in relation to the coil on the pieces of tape.
Remove the wires attached to the sides of the coil. Some wires can simply be pulled off of their coil terminals, while other are secured in place with a small nut. If secured with a nut, rotate the nut in a counterclockwise direction with an open-end wrench until the nut detaches from the coil, then lift the wire off of the coil.
Loosen the coil's clamp or remove the coil's retaining bolts. Coils on older vehicle's are usually secured with a clamp. The clamp is tightened around the coil with a single bolt. Rotate the bolt in a counterclockwise direction with an open-end wrench to loosen the clamp, then pull the coil out of the clamp. Some modern vehicles feature one or more retaining bolts to secure the coil in place. Remove the bolts with a wrench to release the coil.
Secure the replacement coil in place with its fastener(s). If the coil is secured with a clamp, slide the coil into the clamp and rotate the clamp's bolt in a clockwise direction with a wrench. If secured by bolts, install and tighten the bolts in the same manner.
Attach the coil wires to the sides of the coil, taking care not to confuse the positions of the wires by noting the writing on the masking tape. If the wires attach to terminals, press the connector on the tip of each wire onto its terminal until secure. If secured with a nut, slide the metal loop at the tip of the wire onto its threaded rod, then secure the wire in place by tightening its nut with a wrench.
Press the rubber boot on the coil-end of the distributor wire onto its fitting on the coil until secure.
