Cutthroat912

If I wanted to, could I convert a MS3 configured for a 96-97 to a 90-93 simply by changing the pins in the denso connector? Obviously I would need to change settings in Tunerstudio but I'm just wondering if besides settings and pin location, if there's anything different between the na versions of the MS3?

Braineack

iTrader: (62)

the difference is only in the harness.

Cutthroat912

So I would only need to change the harness coming from the ms to the denso plug? Sorry if that's a dumb question, just making sure.

Braineack

iTrader: (62)

the 96-97 has three plugs, the 90-95 only has two

Cutthroat912

In that case, for the na pnp versions, is the only reason DIY sells different years is because the base tune is different?

Ted75zcar

iTrader: (2)

Go to mellens.net and get the wiring diagrams for each car. DOCUMENT and UNDERSTAND everything you need to change prior to starting.

Braineack

iTrader: (62)

no, the wiring between the 90-93 and 94-95 are different enough.

the break down is 90-93, 94-95, 96-97, 99-00, 01-02, 03-05

Cutthroat912

Thanks for the info guys!

Savington

iTrader: (31)

I know exactly how to do this and I would never, ever do it.

Cutthroat912

Can you elaborate on that?

codrus

Screwing with the factory pinout like that is just asking for trouble. At some point in the future, SOMEONE will assume it's still the way it's supposed to be and plug in the wrong ECU and boom.

If you want to run an ECU with the wrong pinout, make a short extension harness that reroutes the wires.

--Ian

Cutthroat912

I may be misunderstanding all of this. I was under the impression that there would only need to be changes to the Ms to make it compatible with my model year. Is this not the case?

acedeuce802

iTrader: (1)

Which MS3 do you have? MS3pro, MS3+MS3x, MS3, MSLabs MS3, MSPNP Pro? This will significantly impact how easy/hard/possible it is to change. If it has a patch harness from a DB37 to Denso connector, then yes, you can modify that harness. If it's a PNP, then it's more trouble than it's worth.

Cutthroat912

Maybe I should have clarified that in the beginning, it's a MS3+MS3X with denso to db37 breakout.

acedeuce802

iTrader: (1)

Check out this build manual that Braineack put together: https://trubokitty.com/#/ms3xassembly

You'll see that the building of the board is common between Miatas (other than a few mods for NB stuff, I forgot if there's any other changes between years), and the bulk of the differences is in the patch harness.

Braineack

iTrader: (62)

yeah, just build a new harness.

Cutthroat912

Thanks for the help!

codrus

You can't easily move pins around inside the ECU because they generally use a solder-on, board mount connector. It *is* possible, but it's going to involve a bunch of work with a soldering iron.

Moving pins in the factory wiring harness is relatively straightforward, you stick a tool in the back of the connector, release the catch on the pin, pull it out, and insert it into a different hole. It's just that you've now laid a land mine for the next guy who works on the car.

--Ian