Yea I was thinking like you two its the (B) that heads over to the ECM. But while looking at it I noticed the (B) only goes to two injectors then to the ECM. Then the (B-R) goes from the other injectors into the OBD test port. So I was guessing that those are the ground signal wires that its looking for. Now my question is should I be able to spade my wire into the test port and then change the referance formula during calibration. Or should I just go and cut into the harness at injector 1 pin 1.