Hi I just got a Greddy Air Fuel Gauge. This gauge replaces the O2 sensor with its own.
I have a question can I just install the Greddy O2 sensor and connect the stock O2 line onto it? I heard that they are different volts and may fry my ECU?

Or

Do I have to weld a new bung for this o2 sensor beside my stock o2 sensor ?

 

I'm not sure but I'd assume you need a new bung.

 

Your in luck, I have mine on my desk. Doesent anyone read the instruction manual?

My O2 sensor fits in my RB downpipe, so Id imagine it fits the stock location.

Now, after you plug the Greddy sensor into its harness, there will be a green wire (signal from greddy sensor) hanging out with a butt connector on it. Youll need to attach your stock O2 sensor wire to it. You can do this one of 2 ways. You can cut it, strip it, and put it in the butt connector, or you can get a piece of wire, strip it, put it in the butt connector, and put a female spade on the other end. The stock harness is just a simple male spade inside of a square connector, so you can easily connect a female spade to it.

If this all sounded confusing, let me know ill make a diagram for you. (Or you can look in the manual on page 5)

It wont fry your ECU, and you dont need a bung.

 

but the greddy o2 is 0-5v I'm sure. and stock is 0-1v. if you had a stock 4 wire o2 that was 0-5v. then I guess you could replace it with the greddy one. but I don't think you can replace the stock one wire with it.

 

Hey Thanks!
I got my Greddy A/F from japan came with no instructions.

Anyways I took a pic. Is this the green wire you mentioned?
Will the reading be egnough for the ECU to read?

 

to be sure just swap that one in. and unplug the stock one. get it warmed up. and get a volt meter on that wire. rev the engine up. and see what kinda voltages you see. if it goes over 1v it's no good. and you'll need to keep the stock one too.

 

Thats the green wire im referring to. Scott is probably right. I was unsure of the stock O2's voltage but I thought the Greddy one was 0-1v too. Check that bastard to be sure.

If you need info on the other wires, let me know.