Coil pack replacement - NB

by Chess Martin

You should be able to swap out a '99 Miata coil pack in about 30-45 minutes the first time with a minimum of mechanical expertise, or even inclination in my case.

First, get the tubes and wires out of your way.

• Unhook the negative battery cable and push the brake pedal once to discharge any residual power.
• The sparkplug wires are bit tough to pull off...I used channel-lock pliers to gently pull them off of the coil. Note the order of the wires (4,1,2,3). If you have the blue NKGs, they are labled with numbers.
• The wires across the top of the coil and the plastic tubing can be removed by pinching the underside of the plastic clips that hold them on (I used needlenose pliers, but that only worked marginally).
• The metal tube (you'll see as it's clearly in your way) can be unhooked on the left end and propped out of the way after removing two bolts in the firewall.

Next, remove the coil.

• Looking from driver's side, note the wire going from the coil pack to the engine block. This can be pulled off by squeezing the flat tab while pulling (by hand).
• Remove the three 12mm bolts that hold the coil pack on with a combo of a 12mm socket with extension and a 12mm wrench (preferably angled). (I have the most problem with the third bolt located at the bottom of the coil pack. There is not enough room in there. I position myself on the passenger side and I put a socket wrench with 12mm sockets on the other side. I guide the end of the socket with my left hand and with my right hand on the socket , I push down. Its in there so tight but finally gave in.)
• Now that the coil pack is loose, you should be able to manuever it in such a way as to remove the two wire sets from the back. This is where I struggled the most.
• You see the tabs that look like they should be pressed in? Push them fairly hard with your index finger while pulling them off with your middle finger and thumb (WATCH YOUR KNUCKLES!) (Its easier to pull the coil pack up and into the top of the engine. With the connectors on top, push the tab with a screwdriver and with another screwdriver, carefully pry upward the male connector. In fact, I find this technique of disconnecting plastic connectors with tabs a lot easier than using your hands).
• Note that one of these wires has a blue wrap, and that the side of the coil it goes on has a blue dot...making them pretty much idiot proof.
• Now that the old coil is off, note the rubber bushing on the bottom that is not on the new part. If you can get this off without damaging it and can get it on the new coil pack, you are a better person than I am. (I was able to remove the bushing by loosening it with a small screwdriver. First remove the center piece. Place the flat end of the screwdriver on the edge of the bushing and carefully hit it with a hammer. You can then pry it off. Put it on the new coil pack).
• I just put the new coil on with the two top bolts and it seems very secure.
  

Put on the new coil in the logical reverse order...back wires, then bolts, then plug wires, then everything else. Hook the battery back up and take her for a spin. If it's like mine, she'll idle a bit strange for the first 10 minutes or so.

Good luck, and watch those knuckles.