I would not guess. Obtain a diagram of just exactly what you have and duplicate it. Sensors on modern EFI are normally "grounded" (signal ground) an insulated conductor running clear back to the ECU connector, not grounded to the block or anything else.
Since you may NOT be running wiring in original positions, bear in mind:
The factory spent a LOT of time fighting and solving EMI/ RFI problems (electromagnetic, spikes, and radio frequency interference)
Sometimes you may have to shield wiring. This on small signal (sensor) cables is normally done with what is called a Faraday shield. The gist of this is that it is a shielded cable which is only grounded at ONE end--the end near the ECU usually
You can also do this--and it is done in fact, with such as telco/ ethernet cabling. You cut loose unused pairs in the cable and tie them to one ground only at the terminal point. Leave the opposite end "float.
Be careful "guessing" It does not take much to 'take out' expensive electronics
