360 magnum O2 sensor install help

Truckie said
Here’s the scenario: 1999 360 magnum swapped into a 67 dart. Running stock efi, computer, and harness from computer to the fuse box. Summit headers with dual exhausts. Right now I don’t have any O2 sensors installed. I believe the donor truck only had on pre-cat O2 that was located just before the cat where pipes joined. I don’t recall an unused plug in the engine harness for the O2 sensor to plug into. I’m thinking the wiring must have come from the large fuse box. Most of that part of the harness is gone. I’m only getting codes for bank 1 sensors so pretty confident the donor didn’t have 4 sensors.

Now for my questions:
1. How can I hard wire the pre cat sensor so it will work assuming that part of the harness doesn’t exist anymore?

2. If I just run one sensor, do I put it in an H pipe so it reads both sides?

3. if the donor truck only had one pre cat O2, how can I add a second sensor for the other side of the engine? Will the computer recognize 2 if the donor only had one?

thanks

1.) There are 3 wires that go to the O2 sensor, 12V switched power, ground and the 5V signal wire that you will need a pinout diagram for you harness to locate.

2.) No. Run the one O2 sensor to only one side of the motor. The 5V input signal it sends will be used for all cylinders. It needs to be closer to the cylinders than it would mounted be beyond the H pipe.

3.) You could call Solo PCM's in Florida and talk to them. If anyone can do the programming changes to add a second sensor, they could, but it is not necessary. You can run what you have once you add the O2 sensor.