Photography by James Wood
Installing a full suite of Haltech electronics–ECU, dash, power distribution module and even a fresh wiring harness–sounds like a clean, efficient, modern solution for a race car. Something a professional team with matching shirts and a Snap-on account would do.
So, naturally, I did it with one of my friends in his workshop, with oil-stained hands, questionable crimping technique, and a stubborn refusal to read the instructions until I absolutely had to. That is my approach and how I ended up in this position.
Thankfully for me and everyone involved, my friend Kevin is a wizard when it comes to wiring. He made sure everything was done properly and more like those professional guys in matching shirts with Snap-on accounts.
The RX-7–my beloved, abused, V8-swapped track weapon–was due for a complete electrical gutting. Years of patch jobs, melted relays, and enough spaghetti wiring to open an Olive Garden meant one thing: burn it all down and start fresh.
And Haltech? Haltech and Kevin were the flamethrower.
First, we yanked the old wiring. And I mean everything: ECU, fuse box, mystery toggle switches, that one wire that used to power the fuel pump and now just made a relay click somewhere under the dash. Gone.
The car looked like a stripped carcass by the end of the day–bare metal, roll cage, gutted dash, scattered wires, a sad pile of relays and corroded connectors in the corner. If race cars could cry, mine would've needed a therapist.
But underneath all that chaos was a clean slate. And nothing screams “clean” like a Haltech Nexus Rebel LS ECU and the PD16 PDM ready to run the whole show.
Installing the Haltech Rebel ECU was weirdly satisfying. Finally, a standalone that speaks fluent LS without needing 10 adapters, three sacrificial goats, and an HP Tuners license.
Mounting was simple: I choose to put it where the old fuse box sat, front and center in the dash.
Plugging in sensors? Smooth. With the Rebel, we get onboard data logging, dual bank wideband control, traction control, flex fuel, dual knock sensors, multi-level engine protection, shock control and a race timer.
Then came the IC-7 digital dash. This thing looks like it belongs in a spaceship, not a 39-year-old Mazda. High-res, CAN-integrated, customizable, and bright enough to blind you in pit lane. LRB Speed sells a simple bracket to mount the IC-7 where the old cluster lived–goodbye analog needles, hello glorious pixels.
I powered it on for the first time and grinned like a man who just discovered fire. Rpm, coolant temp, oil pressure, oil temp, and gear–all there, instantly.
The PD16 power distribution module is the unsung hero of this setup. No more fuses. No more relays. Just programmable logic and solid-state switching that makes you wonder why anyone ever ran power through a crusty 30-year-old toggle switch in the first place.
I used the Haltech flying lead harness because it gave Kevin total control of the setup. Every wire gets crimped, heat-shrunk and routed with intention. It's therapy, if therapy involved more zip ties and less talking about your feelings.
Label everything. Double-check the wiring spreadsheet. Triple-check pinouts. Do not trust your memory. Ask me how I know.
Routing power for fuel pumps, fans, ignition, injectors–it’s all drag-and-drop simple once it's wired. You tell the PDM what to do, how to do it, and when to stop.
And if something goes wrong? It tells you why and where, without a single blown fuse.
If you're not running a PDM in your track car yet, you’re basically living in the dark ages with a flashlight taped to a breaker panel.
The Haltech CAN keypad is a game changer. No more drilling the dash for switches or trying to remember which toggle does what mid-corner. You get 15 backlit, fully programmable buttons, all CAN-controlled, all fully customizable.
I set mine up for ignition, start, fuel pump, fans, wipers (because yes, this thing still gets wet), pit limiter, lights and eight more for future regrets.
Each one lights up with its own color when active, and the labels? Just printed some on clear vinyl and slapped them under the button covers.
The best part? Haltech provides standard labels or, if you’d like to make it fun, they include icons from Mario Kart. The setup is a pro-level feel without the pro-level budget.
Wiring it in took all of 10 minutes: two CAN wires, one power, and boom, fully integrated.
With everything wired and labeled, I loaded the config into the Haltech software. Haltech makes this the start-up procedure seamless.
Here’s what you do. First, get your fancy app on your phone or pull out the laptop. You select which engine you have, what size cam, what injectors you run, and you’re good to go.
The system picked up all the devices right away–no drama. Everything communicated like a happy little electrical family: ECU, PDM, IC-7, keypad, sensors.
We fired it up.
Fuel pump primed like clockwork. The IC-7 came alive with rpm and oil pressure. Keypad lit up like a Christmas tree. It started on the first crank–no prayer circle required.
And for the first time in this car’s life, everything worked.
If you’re thinking about rewiring your car, stop thinking and start doing it with a modern setup like this. The Haltech Rebel, IC-7, PD16 PDM and CAN keypad turned my crusty old RX-7 into a proper race machine with brains to match the brawn.
Sure, it took hours of planning, labeling, and rechecking circuits. Sure, Kevin’s fingers are still cramping from crimping 100 pins. But the result? Clean. Reliable. Race-ready. No more mystery shorts. No more fuse box panic.
Just performance, control, and one pro level RX-7.
Sure, it took hours of planning, labeling, and rechecking circuits. Sure, Kevin’s fingers are still cramping from crimping 100 pins.
It would have taken all that time and effort to do it the old way. In a modern, dedicated race car once you get past the price it seems like the way to go.
Could we get an update from you about a year from now to see how it all worked out?
I feel like I'll be here in a couple of years. 25 year old electronics are terrible. Slow polling rates and really limited features. It just seems like a daunting prospect to strip everything out, but removing fistfulls of unused wiring would feel great.
Questions about wiring (this is very timely)! Here goes from things I'm curious about in this article;
1. What are you using for harness labeling? I think I see clear heatshrink over the yellow labels. How are you creating the yellow labels, what materials and tools?
2. Are you labeling individual wires? I went looking for a heat shrink label printer last night for a project and I don't know how to make heat shrink labels for 20ga and smaller diameter wires. I know there are labels that can be zip tied to wires but uuugh that's not sexy.
3. Are you reusing wire colors from how Mazda built the car originally or is there some other way of deciding what wire colors you used? Perhaps Haltech has guidance and you're following that?
4. What do your wiring diagrams look like, how were they created, etc?
theruleslawyer said:25 year old electronics are terrible. Slow polling rates and really limited features. It just seems like a daunting prospect to strip everything out, but removing fistfulls of unused wiring would feel great.
Yet 40-50 year old electronics are wonderful. The ignition module has been on the Datsun since 1985.
25 years ago folks reactions to my carbureted motor were usually swap to EFI because cabureted cars need constant tuning. Meanwhile they were constantly fiddling with their laptop.
Of course modern EFI is better in every way and it sounds like this new system is truly awesome.
In reply to Noddaz :
I did it the old way and can confirm it took alot less time then doing it the proper way.
I'll let you know how it all goes in a year!
In reply to theruleslawyer :
It does FEEL really good removing old wiring. Its like the fun demo part of a home project, the rest of the stuff is a wee bit less fun.
In reply to Tom1200 :
The thing about EFI is the ability to refine way beyond what carbs and points are capable of doing. That's why people are always on their laptop.
Add to that, you can see which part is causing hesitations or surges vs trying to figure out which fuel circuit in the carb is supposed to be covering something.
In reply to pres589 (djronnebaum) :
1. Yes, you’re absolutely right—you’re seeing clear heat shrink tubing over yellow printed labels. This method keeps things clean, durable, and professional-looking.
We used vinyl, printed using a label printer Brady BMP21.
Protection: The label is applied directly to the wire or bundle, and then clear heat shrink is placed over it and shrunk down. This protects the label from abrasion, chemicals, and heat—critical for anything going into a hot engine bay or under the dash.
2. Yes, individual wires are labeled—especially when you're dealing with a custom harness, it's basically essential.
For 20 gauge and smaller wires, we use heat shrink tubing with pre-printed text. You can:
Use a printer that supports heat shrink material, like the Brady BMP21
Load the printer with heat shrink tubing cartridges, not just regular label tape.
These printers let you size your font and shrink tubing to match wire gauges. For 20-22 AWG, you’ll want 1/8" diameter shrink tubing or smaller.
If you're not printing directly to heat shrink, you can:
Print tiny labels with vinyl tape, wrap them around the wire like a flag, then cover with clear heat shrink to hold it all down.
Agreed—zip-tie labels get the job done, but they’re a last resort. Heat shrink looks pro and won’t rattle loose.
3. In this build, we didn’t follow any of Mazda’s original wire colors because a few years ago I pulled all the OEM wiring out. The colors were determined by the flying lead harness provided with the Haltech PDM16.
4. For harness layout and pinouts, we used Excel was used to make detailed tables for:
Wire color
Source and destination
Pin numbers
Notes (sensor type, shielding, etc.)
In reply to alfadriver :
In my case anything other than main jet changes for seasonal weather shifts is whizzing up a rope. The Keihin Flat Slides on my Datsun work flawlessly.
Additionally the folks I saw on laptops (admittedly a small sampling) seemed to be chasing problems. Said problems could have been of their own making.
In fairness I've watched people trying to get that last 1/2 horsepower out of carbs screw them up monumentally.
To me good carbs (emphasis on good) were a better solution than aftermarket EFI from that time.
Using a label, wrapped like a flag under clear heatshrink, is an awesome solution. Sounds like you really aren't creating diagrams but for the most part they're probably not that needed if the Haltech setup comes with pretty comprehensive wiring. Creating a whole-car setup from scratch probably comes with different requirements.
Great feedback, thanks.
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