Finished getting my car back together and have a small problem, although the car runs good it has a check light which i believe to be from not having the right 02 sensor for the computer.

car is a Vp,
engine, ecu and gearbox is a Vn manual,
loom and 02 sensor is a Vr manual

i have a Vr ecu here with the security removed but it wont start with it, i read somewhere on the forum that the loom needs a extra power feed but the post didn't say exactly where? i noticed on the 6 pin connector near the battery there is a extra red wire on that isn't on the Vn manual loom, is that the wire?