With over 155,000 miles on the engine in our '97 Jeep Cherokee Sport, we were well beyond the service life of the possibly factory-fit spark plugs, not to mention the spark wires and other ignition components. In an effort to squeak a few thousand more miles from the aging mill, we decided to tackle a few easy installations that would help re-ignite the ignition system and get our 4x4 firing with confidence. For some one-stop engine-parts shopping, we looked to Summit Racing, which was able to provide all of the items we needed for this installation. With the order placed, the Summit Racing parts arrived in just a few days and took just a few hours to install. Check out the photos and captions for all the details.
Summit Racing supplied one of its Volt Max X-Treme spark-plug wire, distributor cap, and rotor kits, along with an Accel Super Coil, a new ignition control module, and a set of Bosch Platinum +2 spark plugs. Also shown is a new throttle-position sensor, which we'll install during an upcoming air-intake and throttle-body installation article. | 
The factory plug wires were in somewhat decent shape despite their age, but the outer sleeves were heavily corroded, which can affect the transfer of spark energy. Before removing the stock components, we first disconnected the battery and also used an air compressor to blow dirt and debris from the spark-plug locations. Loose or damaged boots or terminals, or cracked, burned, or worn wires, could create issues within the ignition system. | 
Before removing the distributor cap and wires, we numbered the wire connections to the distributor cap to indicate each one's corresponding cylinder from front to back. This is not the correct firing order but simply an easy way to remember what wire goes where when the new parts go on. Leaving the wires connected to the cap is also helpful. When removing the spark-plug boots from the spark plugs, you should wiggle and gently pull from the wire boot only. |
The rotor tip was pretty well burned, and the center was also somewhat torched. We thought ahead and ordered a new ignition module from Summit Racing, and sure enough we snapped the old one in half trying to remove it from the distributor. Although the stock ignition module likely had some service life left, it was a good time to replace it since the cap was off anyway. No one likes a weak link either, and we'd rather swap in a new ignition module now rather than on the side of the road somewhere down the line. The stock ignition coil is also visible just to the right of the distributor. | 
The ignition coil was removed along with the ignition module and rotor. | 
The Accel Mopar Super Coil is shown with the factory coil. The Accel coil is said to provide quicker starts, improved idle, and crisper throttle response, and is compatible with JTEC computer-controlled ignitions. The coil offered a bolt-in/plug-in installation without the need for a wiring adapter. |
With the plugs removed, we installed the new Bosch plugs, careful not to overtighten them. The Bosch plugs feature a platinum center electrode and two yttrium ground electrodes. The platinum offers good conductivity of heat and electricity and also does a good job of resisting chemical corrosion and electrical erosion. Additionally, platinum virtually eliminates electrode wear, which can easily double the normal service life of a spark plug. | 
The new ignition module, rotor, and Accel Super Coil were then installed. | 
As a final step, the cap and wires were installed, and the wires were routed to the appropriate plugs. We found it easier to match the wires to the cap before installation and then connect the wires to the plugs. The spark-plug wires feature an ultralow-resistance wire core wrapped in a silicone jacket and use stainless steel terminals with hardened snap locks. Silicone boots can operate in temperatures up to 450 degrees F. |