Alright 2 questions about this swap.

His car is currently an 86.5 atx engine code 7mge

He purchased from an 87 88 year a turbo motor with turbo and what not, 7mgte

Now first he has an ece out of a 90 atx turbo supra and he is swapping to an mtx will this work? Will it work with the motor?

I know usually atx can work with mtx chips but not the reverse.

Lastly he is having a hell of a time finding a wiring harness does he have any other options, other than the obvious stand alone ecu l