3 wires to CKP sensor: power, ground, signal to ECU
3 wires to CMP sensor: power, ground, signal to ECU
2 wires to VVT solenoid: power, ECU switched ground

You could easily run new wiring and not touch/hack the car's original harness so it can go back to swap post engine swap.

I have a lot to learn, but Matt and Jerry's book helped me understand a lot of things and contributed to my excitement over learning something like this.

What do you guys have in regards to an assembled MS3x box that an idiot like myself can put in my car without board level modifications?

edit: After this daily driver gets the VVT engine swap, and I find a better car, it's getting cut up. This car is TERRIBLE. It's one of the most cosmetically disgusting Miatas you've ever seen...but no one wants to steal it.

You have me wanting to do the VVT swap on the yellow car more now.

An off the shelf MS3X would do it, but would need one basic mod. It's $12 if you want us to do it, or I can walk you through it if you want to do it. It's really easy.

Thanks. I'll chew on this for a few months now.

I'm in the same boat. I won't upgrade to MS3 unless I can build it from source. I don't care too much if it's Open Source with capital letters, but if I can't modify it I'm not interested.

Definitely use the stock NB sensors. You absolutely require the 2001 cam sensor as Ben mentioned. It sits on the valve cover and is responsible for providing cam timing data to the ECU.

I assume I can find the required settings for the VVT stuff in one of your threads, right? Is there an MSQ floating around that I can use to get the car started?
I'm guessing I'll need to run "NB+" settings for:

• CMP
• CKP
• spark
• IAC
• VVT

while I run NA settings for:

• Fuel pump
• AC
• alternator (not really any settings for that but I have a spare '99 bracket)

How will I make the tach work?

I'm worried that I'm over-simplifying this.

There really are no "settings" for NA alternator and fuel pump. A/C command can loop through the MS3 to allow for idle up and fan activation. A tach output pin with 0-12V square wave output is provided.

There are msq floating around that should be able to get you started. What year is your DD? I think you said 95. Is that correct?

For the Cam and Crank sensors I ran them through my stock CAS wires. There are 4 wires for the stock CAS. 12v, ground, cam, crank. You can find out which is which in one of the MS threads. Basically you hook the 2 grounds from the NB cam and crank sensors to the grounds CAS wires. Then do the same with the 12v wire, you can also attach the VVT pwoer wire to this. Then attach the cam signal wire to the correct wire on the CAS plug, them do the same with the crank.

For VVT you run a single wire back to the MS3x db37. I routed mine through one of the stock EGR wires that I was no longer using.

Spark depends on if you are running sequential spark or not. If you are you will just have to run 2 additional wires back to the ms3x harness.

Any reason why you can not just run your older throttle body on the new IM? I was planning on just reusing my 94 TB when I was going with a 99 IM.

For the alternator you probably just want to run a 94-97 alternator. That way you don't have to worry about it.

I've got maps for all of it (except alternator) smeared on the internets.

the process isn't too hard. I wrote up a VVT procedure a little while ago that seems to work ok.

Big thanks to everyone for the help and spelling this out to someone who had to take Cal1 and Cal2 three times each to pass.

I'll gather all the information and post it in here when I get ready to roll with the swap. I already picked-up another LC-1.

There was an actual bug in the MS3 code in alpha6, the ignition timers would overflow when the RPM was low enough in the Miata 99-04 wheel decoder (the timers overflowed as the time between the tach events were "unnaturally high" when the RPM was lower than ~160). James found the bug and corrected it in alpha7 IIRC.

we are on alpha11 now.

Any reason why you don't install the MS3x before the engine swap? You could theoretically get it up and running on the old stock engine. Get used to the difference, then convert to sequential fuel and spark. Then swap in the VVT motor and swap to NB sensors.

Holy shit Lars, brilliant post, thanks for the wiring tips.

I STRONGLY recommend sequential. Only requires two more wires.

Well it depends if he want full sequential and what year his DD is. On a 90-93 non-cali car he needs to run 4 wires for full sequential. Two additoinal wires for fuel and two more for spark.

The best idea is to sell your VVT stuffs to me.

this car is from 1995.

I suppose I could get it up and running on NA sensors first, then swap, but if I'm already familiar with TunerStudio is there any point in doing this?