Installing Air/Fuel Gauge with stock O2 sensor still there?
 

Okay, I've got the two O2 sensors in my exhaust now right after the turbo. However, the stock O2 sensor only has one wire coming out of it. The instructions are expecting like two or something wires coming out of the stock one. Has anyone done an install on an Air/Fuel gauge? Can you help me out here with this? I've got it already installed, just need to wire the sucker up correctly.

well i got my connected easy only 3 cables, one is ignition i think is red ,next is black ground , last is purple which it goes to the O2 cable that is coming out (O2 only have 1 cable coming out ,if i am right)

Why two O2 sensors?
If you're connecting an A/F using the stock O2 sensor, don't make connections at the sensor itself, as this ofter causes problems. Make the connections at the ECU. The gauge will need power, earth and signal, all of which are easily found at the ECU.

no, I have the O2 sensor that goes with the air/fuel gauge.

Do I just leave the stock O2 sensor alone, and wire the Air/Fuel gauge on its own? Or do I tie them in together? Or what?

Boy, someone just bent you over and sold you something you didn't need...the extra O2 sensor.

The AFR gauge can easily "tap" into the stock O2 sensor wiring without screwing anything up.&nbsp The extra O2 sensor is a waste of money.



-Ted

Plenty of people have tapped in at the sensor and disturbed the wire shield, grounding both the ECU and gauge signals. The unshielded part of cable at the ECU end is much safer.

I'm sure Ted meant tap into the wire at the ECU ... you would have to be a moron to actully wire it at the sensor itself.. pain in the ass and too damn hot on the wire.

well whoever the moron is that had the car before me already cut the wire, and all that I've got left on my wiring harness is a red wire that sticks out of the harness, and another piece of red wire spliced onto the O2 sensor wire.

Can I just take the friggin' aftermarket (4 wire) O2 sensor and wire it onto that red wire for the signal to both the ECU and the Air/Fuel gauge, ground it somewhere else, and what do I do with the other 2 wires?

*hate it when my post moves to the next page without an answer*

The 4 wires are most likely .... 12Volt, Ground, O2 sensor, and the last one is prolly for data logging, don't worry bout the data logging wire unless you have a good after market EMS.

I would hook the O2 sensor back up the way it was. and splice into your power, ground and O2 at the ECU.. its cleaner, less wire to run & will work perfect you can get all three of your connections in one place.

I don't know whats up with a 4 wire O2 sensor??? Maybe its not for a RX. I was thinking you meant your A/F guage was a 4 wire.

Yeah but I think the stock O2 sensor ISN'T grounded correctly now, now that whoever had the car before me spliced the wire wrong, and the ground sheathing isn't there anymore. Will an aftermarket O2 sensor (the one that I got with the A/F gauge) work on the RX-7? And if so, there's just one wire that I'll end up using for it for the signal, that'll get spliced to both the A/F gauge AND the ECU, correct? And then ground will go to ground, and power to power, and the 4th wire from the O2 sensor can just dangle in the breeze

Thats easy, 2 wires are your signal wires (high and low) and 2 are for the heater.

Did they give you a diagram with the new 02 sensor? And, sorry, but is there anything left of the wire on the original 02 sensor? Anyway I'd chunk the old sensor and put in the new one. They had to supply instructions on which wire is which on that sensor.

Ok it sez...

Balck wire from O2 sensor goes to gray wire on air/fuel gauge
Gray wire from O2 sensor is grounded to the engine block
Power (+12v from ignition on) goes to one of the white wires, the other white wire will be grounded to the engine block.

So I'm guessing it doesn't matter WHICH white wire I power. The gray wire on the O2 sensor looks like the ground, and the black one looks like the signal. Should I Just tap into the black one for my signal for the ORIGINAL O2 sensor?