How to Replace the Ignition Coil in a GMC Sierraby Contributor
The type of ignition system you find on your GMC Sierra depends on the type of engine you have. 4.3L, 5.0L, 5.7L and 7.4L engines use a distributor ignition system that relies on a Sierra ignition coil to trigger the spark plugs. 4.8L, 5.3L, 6.0L and 8.1L engines have a distributorless ignition system that works with an ignition coil pack.
Remove the Sierra Ignition Coil
Prevent accidents by disconnecting the negative, or ground, cable from the battery. You may want to isolate it for added safety.
Use masking tape to tag the wiring connectors that attach to the ignition coil. The ignition coil is inside the distributor, which connects to the intake manifold, so you may need to remove the distributor cap to see the connections.
Disconnect the ignition coil mounting bracket, which holds the Sierra ignition coil, from the intake manifold. You'll need to undo the fasteners with a socket set, wrench or screwdriver.
Determine how you can release the ignition coil from the mounting bracket. Some brackets connect with rivets. If this is the case, you need to drill and punch out the rivets. You'll also need to replace the rivets with screws or another suitable type of fastener.
Release the ignition coil from the mounting bracket.
Install the New Ignition Coil
Insert the new Sierra ignition coil into the mounting system.
Secure the ignition coil in place by inserting screws or another type of fasteners into the mounting bracket holes, if you had to drill rivets. An ignition coil kit typically comes with mounting hardware, so you may want to consider buying a kit rather than just the part.
Reattach the mounting bracket to the intake manifold. Tighten the retainers until they feel snug--too much torque can strip the fasteners.
Reassemble the rest of the parts by reversing the removal process.
- Expect slight variations in the process due to different types of engines. For example, you may need to remove the air cleaner outlet resonator and nut in order to access the ignition coil, as is the case on 4.3L engines.