Tommy3970

new member here, youll see a lot of me this year. picked up a clean 97 miata, but its one of those unholy automatics. ive scoured the internet looking for some answers on a specific question and i cant figure anything out. Im picking up the trans and all needed stuff for the swap to 5 speed in a couple weeks. i plan to build and turbo the car, the question that lies here, is, i want to run a pnp megasquirt, how would that work on a 5speed swapped miata? do the connections work from the auto harness? if not is there a way to do it without having to swap the harness? any other tips or advice along the way is greatly appreciated. thanks again

MetalMuffins

iTrader: (1)

I've looked at wiring harness diagrams for the NB a fair amount, so not direct, but with those ECU / harness the connectors are the same, so no issues there. Once you have your PNP standalone connected, all the automatic specific pins will just be optional ECU outputs for you to program as you see fit (likely ignoring them). I wouldn't foresee an issue, though I'm saying that with zero direct experience.

See if you can find the 97 cassis wiring diagram and confirm it's the same there and your golden

Roda

I swapped my '99 from auto to 5 speed, and intend to eventually install an MS3. As MetalMuffins noted, the ECU should plug in and work no problem. You may have to change a few pinouts due to the swap, but that should be pretty easy.

The swap itself is pretty straightforward mechanically. You may have already found these, but I found them very helpful when doing the swap:

Miata Wiki - Auto to Manual Swap

MT thread - Auto to Manual swap wiring

Midtenn

iTrader: (15)

If you're doing a Megasquirt, you really shouldn't have any issues doing at AT>MT swap. I did one on a '96 and fought getting the ECU to stop throwing CEL's for transmission faults. I did not change the chassis harness. Just "tricked" the ECU into see what inputs it wanted to see for start up. So if you swap in a standalone, it shouldn't be an issue because it won't care about AT/MT stuff.

Tommy3970

WOW thanks for all the awesome feedback, that really starts me in the right direction (at least my auto engine has a variable tps already ) yeah I'm not concerned with anything mechanical, just the electrical is above my head, never spent the time to learn it all properly. i have a check CEL due to a gas cap,and for the life of me i dont know why, i think theres a bad sensor, and of course an airbag light cause aftermarket steering wheel. since i have all of you here, theres a plug under driver dash close to obd that is unplugged, when plugged in, theres a strange buzzing sound coming from the area, almost like a horn with a really dead battery, any idea? i just leave it unplugged and car runs fine.

MetalMuffins

iTrader: (1)

Door buzzer with a bad door switch would be my first though

Tommy3970

Door switch, I never thought that that could be the buzzing as I had my door open and doing yoga to be able to plug it in anyways. Hmm. May not even be a bad switch