Spark Plug Installation

Seems like a silly thing to put on here, but not everyone knows how to go about this, so here it is!

1) The spark plug portion is relevant to everyone, and is posted at the top.

2) The distributor/wire portion of this write up is specific to Wranglers/vehicles with a distributor (post distributor vehicles have coil packs above the spark plugs, so this is irrelevant to those, which I believe are post 1999 Wranglers) and is more towards the bottom.



On with the show.......



1A) Spark plug replacement! In order to swap out spark plugs, you're going to need new parts to put in! I got mine at AutoZone, and they are the AutoLite AP985 plugs. Locate on the engine block where the spark plugs are. Remove the wires if applicable, or the coil packs if you are post '99. Underneath will be the spark plugs. You'll then need your deep-socket spark plug socket, which is usually a 6-point 5/8" tool. Once you've got that set, grab your socket extension and stick it down into the spark plug. Once seated, begin to back it off. Might be a bit of a challenge at first, but you'll get it.

The next step is to put in the new plug. Before you do that, make sure it's gapped correctly using a spark plug gapper tool. Simple enough, just make sure the right gap is in place. My wrangler was .035. My OLD plugs were at .050!!! New ones made the idle much smoother. Once they're gapped correctly just re-insert them to the engine block and tighten down. There is NO need to overly tighten these parts. A simple hand tight will be just fine. After you've got all the plugs replaced, return the coil pack or wires to their appropriate plug, and you're done! Simple as that.


Wires into engine block on a 99



Old vs. New








2A) For the rest of the stuff, 1999 wrangler and before, I got mine at AutoZone for about $60 in total. This included new wires, a new distributor cap, and new spark plugs. The spark plugs themselves are the ones most recommended on JeepForum and across the internet for my Wrangler, the AutoLite AP985. Wires and plugs are simple, just get whatever fits your Jeep. There really is no build difference to the distributor cap, a piece of plastic with some metal tips, although some people may think there is.

The first and most important thing to note when installing new cap/wires is that you MUST KEEP TRACK of where the wiring order. Messing that up will ruin your ignition sequence and your Jeep will not start. SO with that being said, I find it best to replace 1 wire at a time. START WITH THE CENTER WIRE, IT"S ATTACHED TO THE POWER, you'll want it removed first. You can quicken the process by putting the distributor end of the new wire on the new cap, by noting where the (1) is on the top of the cap, and aligning it with the cap in the engine. Then it's a simple swap.

Once you've replaced all the wires between the spark plugs and the new distributor cap, and are SURE they're in the right order, go ahead and remove the old cap. This will be done by 2 phillips screws on the sides of the old cap. Go easy, they might be seized in place. PB blaster will help in small quantities. Once it's off, remove the old plastic tab on top of the distributor. It's as simple as pulling up and off, and replacing with the new one. Then screw down your new distributor cap with the new wires, and you're good to go!