I am having trouble finding where to wire up the first o2 sensor for the si motor. The HX is originally a 7 wire and the si is a 4 wire so I need to find where to wire into the HX harness with the 4 wire. I know any other harness would have worked better but I am this far already so I gotta make it work. Also I have read about a 5 wire working in the first o2 bung but I am not sure. Please give guidance.