Last night I finished ohming out all of the connections to the Haltech. I found one error where a bunch of +12V switched signals from one of the main relays were supposed to be ganged together and I had missed one. After connecting that properly I plugged in the ECU and turned on the ignition. To my surprise, the fuel pump ran its 2.5s prime cycle. I didn't expect that because you can't load a tune into the ECU until it's powered up. Regardless, that was encouraging. I connected the laptop to the ECU and the gauge package came up with no issue. It automatically calibrated the DBW throttle, which seems to work very well. All the sensors gave plausible readings for temperature.

I have a few more things to check before I put the intake manifold back on and button it up but it looks promising. I like the Haltech tuning interface so far. Very flexible and intuitive.

That is exciting. Congrats. How long do you think until you get behind the wheel and can take it for a spin?

I should have the shocks back this week, so... Could be this weekend if things go well

What terminals are those? I’m constantly working on wiring.

:+1

I don't know enough about this to ask intelligent questions, so if it's OK I'd like to ask some dumb ones.

1. Is all of this wiring needed because you put the a different engine in the car? Or is some of it needed because you also decided on some custom engine management for performance? Or because you added a turbo?

2. You said the Haltech harness is clearly labeled. Is it specific to the miata engine, and you need to figure out how to connect all the inputs that it needs? Or are there some standards, so you bought a harness designed to connect a Miata-type engine to an RX-8-type chassis?

3. Insert questions here that I don't enough to ask but will want to know once you answer 1 & 2.

Non-insulated crimp terminals. Basically a barrel sized for whatever gauge wiring you're working with. Peter suggested to me that he's used these for years and they're very robust. I don't like soldered connections for automotive use because they are brittle. Ballenger sells these. So does Digi-Key.

https://www.bmotorsports.com/shop/im...00x300_mat.jpg

https://www.bmotorsports.com/shop/pr...3nunug5gc0niq0

The wiring is needed for the Haltech. Once I had the car running on the stock Mazda ECU I could have just used that as the basis for tuning the engine, but it lacks a few features that I wanted. First being flex fuel capability (E85 or a blend of it). Second being anti-lag for the turbo and third being launch / traction control. I ended up picking the Haltech because it has all of those features natively built-in.

It's a universal harness and a universal ECU. Meaning, it has 'X' available analog inputs, 'Y' available digital outputs, and requires certain voltage and trigger inputs to work, like a crank angle sensor, cam angle sensor, water temp, TPS, etc. The end user determines how many widgets they want to control (like wastegate solenoids, the alternator, etc) and how many additional inputs they want (like oil temp and pressure sensors, fuel composition sensors, etc). The end user then wires them up appropriately, configures them in the software, loads that tune to the ECU and goes from there.

Holy crap that's awesome. So you are going to make all your own mappings for controlling everything?

Because that's also terrifying. So.. many... knobs to turn. I assume there are some sane starting points, and then you will tweak from there?

I have a "base map" from a guy that did a Haltech install on his NC Miata, which is basically what my car is at this point. I'm hoping it works, because it will save me a lot of time in getting the basic engine configured. But people have been doing this for years, there is a process for developing a base fuel / spark map.

A few neat features of the Haltech...

The DBW curve is fully customizable. I could make it super soggy at low throttle openings like a Prius if I wanted, or have 10% pedal travel translate to 50% throttle opening like an E46 M3 in "Sport" mode.

It integrates with the Mazda's CAN bus, meaning it can drive the stock gauges, interface with the ABS (for determining wheel speeds for use with traction control), etc.

It supports boost trimming. I.e. I can have a position switch on the dashboard with "n" states, each translating to a different tune. I could take a run on one setting, then dial back the peak boost level if desired. Or dial it up. Kinda cool.

Flat shift. You can program it to allow shifting without lifting off the throttle. It will periodically cut spark to hold rpm while maintaining boost between shifts while not allowing the engine to over-rev.