Hi guys, I'm working on a '90 Integra with a GSR swap. The car came to me pouring coolant and oil out the pipe and way low on compression. Pulled the motor and did a full rebuild. Its now back in the car and running great. The car is still obd0 and running off some kind of obd0 ecu with b16a written on it in marker.

My issue is, as soon as the key is turned to ON, regardless of starting the car or not. Weird thing is the car runs great and the rad fan cycles as normal. I tried plugging in a pr4 I had kicking around and same thing... code 6 right away. I'm sure there is something messed up with wiring somewhere I'm just not sure where to start. My honda experience is limited to my own 4th gen civic with a d15b converted to multiport and obd1.

I have contenuity from the ect sensor connector (cyl head next to the gauge sending unit) back to the ecu.