We all know that rx-7s of all years suffer various electrical issues and hesitations, largely attributed to poor grounding and charging. ON top of this, all cars 10+ years old develop charging issues due to age and corrosion, and poor connections. Because of this, many seek to rewire their charging/ground system. There are kits sold on ebay, but you can hardly expect quality from a 20 dollar wiring kit, when quality 4 gauge wire alone sells for $2.50/foot or more.
For time, fitment, and availability reasons, I choose to make my own kits. I do so from high grade 4 gauge power wire, obtained at most any local stereo installation shop. Also get the appropriate 4 gauge heavy duty ring terminals for the wire here. In addition, you’ll need new battery terminals (the FD only needs one), available at the stereo shop, auto parts stores, even walmart. You’ll need electrical solder and a small propane torch (a solder gun won’t cut it for these big terminals, you’d be at it all day). A vise is very helpful for making the crimps on the large terminals as well. Total cost for the project is under $100 most of the time, and it’ll take about an hour to make, a bit more to install. With a good battery and alternator, you can see voltage increases of .5-2.5vdc. This helps with lighting, idle quality, hesitations, etc. in some cases (if you had a problem to begin with).
Make the following connections (in addition to the stock wires) which vary by car:
-battery + terminal to alternator + post
-battery + terminal to starter + post
-battery terminal to chassis (bare metal) at strut tower
-battery terminal to top of block (where wiring harness bolts down)
-ground to alternator body
-ground to starter body
This gives clean, high voltage signal to the starter, alternator, and engine wiring harness/ecu. BE sure to clean all connections and tighten securely during installation.
For 2nd generations, you’ll need 10 foot of ground wire, and about 8 foot of power. You can use the same wire if you want, this is personal preference. Ground is normally black, power is normally red or yellow. It’s the same wire, just color coded for reference. You’re going to make 6 wires, so youll need 12 terminals. You’ll use 2 battery terminals, and be sure to clean off the battery posts if youre using an old battery. You’ll cut positive wires in 38” and 52” lengths, and ground wires of 18”, 44”, and 2- 24” lengths. The longest positive wire goes to the starter, the other to the alternator. The longest ground wire goes to the top of the block, the shortest to the strut tower frame. The other 2 bolt on top of the one we ran on top of the block, one going to the alternator mounting bolt/body, the other going down to the starter body.