You might suspect that your Ford Expedition is having issues with its ignition system. In many cases, the stock ignition coils are not robust enough to handle long-term starting and will need to be replaced over time. Removing the ignition coil on a Ford Expedition is not difficult. You can do it in just a few hours in your own garage and replace the stock Expedition coil with a stronger aftermarket coil that will last for years to come.
Park the Expedition in a level, open area, and pop the hood. Disconnect the negative battery terminal; locate the ignition coil interface on top of the engine and near the battery box. Remove the plastic shrouding that covers the top of the interface and locate the electrical connections underneath. It is often a good idea before beginning to work on the coils to use a wire brush to remove any oxidation that has built up on the exposed terminals. Sometimes, this might even fix your ignition problem as oxidation can drastically reduce its performance. You can also use a diluted solution of baking soda and water to dissolve the oxidation.
The ignition interface is actually the connection between the ignition coils and the ignition switch. To access the ignition coil, it is necessary to remove the ignition interface itself. Use a crescent wrench to remove the bolts holding the wire connections to the interface, and remove the wires. Unbolt the interface from the ignition coils and lift the interface free, exposing the ignition coils beneath.
Remove the two ignition coil mounting bolts and the one center stud bolt. Disconnect the wiring harness running to the rear of the coils. Lift the coils out of the engine compartment. Inspect the ignition coils for wear and tear. Look for brown or black burned areas and search for oxidation. Oxidation is an indication that there is not a complete connection being made somewhere in the coils. This oxidation and lack of connection could cause your coils to wear unevenly. If this is the case, make sure to tighten the coils completely down to the recommended torque when installing the new set of coils.
