I've got an 89 hf with obd0 b16 I got about a year ago with the wiring harness all chopped up, I know there are 2 o2 sensor but I just don't know the wiring colors any help would be appreciated so I can clean this mess up and get on the road.
An 89 HF along with all 88-91 USDM CRXs only have one O2 Sensor. I think there may have been some JDM and EDM OBD0 engines that did have two O2 sensors.
You need to see what ECU you have in the car and look up it’s pinout to see if it requires two sensors. If two sensors are required you need to use either the stock manifold for that ECU or a 4-2-1 header with two bungs just past the 4-2 junctions. Looking up details on the ECU will tell you the cylinder pairing for each sensor.
The O2 sensors use a shielded type wire to reduce noise on the signal. The inner core wire is white. The outer jacket may be gray. The strands of wire that form the shield get gathered together and connected to ground at one end. If you need to run a second wire or repair the original you can use a small diameter coax cable like RG-174