Automotive ignitions have evolved over the years from distributor to electronic Hall effect, to distributorless with ignition coil packs atop a control module, to individual ignition coils on every plug. The coil pack period relied on a wasted spark system where one coil would fire two spark plugs simultaneously. One spark was on the compression stroke and the other on the exhaust stroke.
Remove the negative and positive wire from the top of the coil. These systems utilize a singular coil located on the firewall near the distributor or on the intake manifold near the distributor. The black negative wire is to the points and the red positive wire is direct to the ignition terminal on the back of the ignition switch. This causes the coil to have power when the key is in the on position.
Pull the coil wire out of the coil's tower.
Loosen the coil mounting bracket pinch bolt using either a screwdriver, in some cases, or a socket, in others, depending on the year and make. In all cases, the pinch bolt will be in the middle of the bracket--it tightens the bracket around the coil. Lift the coil out of the bracket.
Locate the coil packs. This is easy since all that is necessary is to follow the spark plug wires to the coils. These systems use one coil for every two cylinders. A 6-cylinder engine would then have three coils and so on. The coils are grouped together and sit atop an ignition control module. The coils are connected to the control module by the negative and positive wires between the coil base and the module. Some foreign cars such as Isuzu have a separate control module and the coils sit under a cover in the center of the engine. General Motors Quad 4 engines have the module located in the cap on the top of the engine, with the coils attached to the cap itself.
Remove the electrical plug in the control module using either a 7 mm or 8 mm socket. Loosen the bolt and pull the plug out.
Number and pull the spark plug wires out of the coil packs. Remove the two bolts in each coil pack using a socket. Lift the coils up slowly and disconnect the two wires under each coil.
Disconnect the electrical connector on each of the coils.
Pull the spark plug wire out of the coil if it is the type with plug wires. Some coils sit on top of the plug with a rubber spark plug boot attached to the bottom of the coil. The coil tower faces downward on these. Some coils, like in Mercedes and other foreign cars, have two spark plugs for each cylinder and two plug wires to each coil sitting over the cylinder. In this case there would be eight coils and 16 plug wires.
Remove the two bolts in each coil and remove the coil.
