Getting it running Part 1

I wasn’t really sure the best way to word this section’s title, so we’ re just going to call it “getting it running” because although the swap is not terribly difficult, there are lots of little things that need to happen to get this 13B into running order. First off is the wiring setup. We took the entire engine harness, ecu and misc chassis harness bits from our donor car in order to make the 13B EFI happy in it’s new home.

We ran the existing ignition harness that the car came with through the appropriate holes and made those connections as they were. Hooked up the starter and installed a battery tray and battery,which we’ve now relocated into the cabin to better weight distribution, and gave it crank. Add a little starter fluid and the engine growled to life. Ignition, check. Now, this was done with NO exhaust on the car, so needless to say, we won’t be doing that again any time soon 🙂

These are a just a few pics snapped during that process. Since this isn’t a well documented swap, and we’re using parts from about three different Mazdas, you can begin to get the idea of what a few of my nights looked like in the garage testing and tracing wires around.


After the ignition and starting side of the electrical is taken care of, we needed to start getting the ECU installed. First up was to route the main harness. The firewall had a “bump” in it that looked like the perfect spot. A hole saw later and we’re in business.


Most of this goes out of order as we’re trying to do five things at once, but progress was moving pretty slow. It seems like whenever you work on a car built by at least two or three other people in the past, NOTHING works as it should. Bolts are mismatched, wiring changes colors six times and has more daisy chains than I care to think of.

Once the harness was pulled through the firewall and some clean-up done, the ECU needed to be mounted. The biggest issue here is that the floor on the passenger side is very wrinkled and the exhaust runs under it. We opted to make a mount that gave the ECU an air gap and gave us the best place to service the ECU in the future. Nice thing about race cars and a budget build, we don’t really care about how it all dresses up. Here’s what we came up with.


The small wire is an extra grounding strap I made to ensure the ECU gets a solid ground to the chassis. A bit overkill, but grounds are crucial on these old electronics. Once the car is complete and we move onto in the final stage, all unused connections will be clipped, tied back, etc. The wiring harness gets tucked when all is done as well. A few more wires and fuel and this will be all set to go.

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