If you have the 89+ 7MGTE harness, it is technically possible to convert it to work on a 1JZ non vvti. There is quite a bit of work involved. Unfortunately, this mod was done before I was into the 1JZ game.
It would just be a matter of gutting the harness and adapting the 2JZ sensors as needed. The 89+ ECU pins are the same as the 1JZ so it would just take some work to adapt.
If you have more information about this old mod, please let me know.