1990 miata with 96 motor, tps with megasquirt?
 

i have a 1990 miata with the flyingmiata fmll kit running megasquirt pnp. im going swap the motor with a 96 1.8. can i use tps?

Yes, just plug it in with a new pig tail and start tuning.

if its the auto 4 wire TPS then yes, if not no

New pig tail? The one on the 1.8 has a 4 wire and the one on the 1.6 is 3 wire

How should I wire it up?

https://www.miataturbo.net/megasquirt-18/how-wire-analog-tps-ms-90-93-car-36271/
I used the directions when I swapped my 96 engine + engine harness into my 91.

my suggestion is, fuck the instructions. splice the wires without soldering. Then go into TunerStudio and calibrate TPS. If you get ~100 for 0% and ~900 for 100% then it's wired correctly. there are 3 wires, giving 6 different combinations total.

You can't break a TPS sensor because it's basically made out of 4 pieces. You can only wire it wrong. e.g. if you're reading 700 for 0% and 800 for 100% then it's wired wrong.

edit: and yes, you need 1.8 pigtail OR you need to use throttle body spacer + 1.6 throttle body.