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Hey everyone,

Just need some help. Im installing a jaycar smart air/fuel display, and i just wanted to know which wire on the ecu is the o2 sensor signal. I have a 94 clubman..

I have been using a multimeter to try and pinpoint the wire. I think its supposed to work between 0-1v (voltage increases with load) and I have found 2 wires that increase their voltage with load.

Brown/Yellow stripe
It stays on 200mv at idle, and raises to 1050mv at full load.

Red/Blue stripe
It stays on 500mv at idle, and raises to 2000mv at full load.


Dose anyone know which one is the right one? They are probably both wrong..

Check the colour at the engine end. Follow it back from the exhaust to just behind the intake cam - there is a single wire plug there.

I think it was red and blue on my 1.6.

Boags

green_comet wrote:Hey everyone,

Just need some help. Im installing a jaycar smart air/fuel display, and i just wanted to know which wire on the ecu is the o2 sensor signal. I have a 94 clubman..

I have been using a multimeter to try and pinpoint the wire. I think its supposed to work between 0-1v (voltage increases with load) and I have found 2 wires that increase their voltage with load.

Brown/Yellow stripe
It stays on 200mv at idle, and raises to 1050mv at full load.

Red/Blue stripe
It stays on 500mv at idle, and raises to 2000mv at full load.


Dose anyone know which one is the right one? They are probably both wrong..

flicking through the enthusiast's workshop manual, this what they have to say in regards to checking the O2 sensor (in a compressed, copyright-safe, format ):
1. There is a diagram of the heated o2 sensor connector(the one with the plug on it-I guess that is the engine side of the wiring, and not the o2 side), terminal A is the upper left plug when facing the connector.
They say use a voltmeter capable of reading low voltages-which you have-and ground the -ve and the +ve goes to terminal A.
start motor and run it at 3000rpm until meter shows about 0.55V.
Suddenly open/close throttle several times and check
that when revs increase a reading of 0.5 - 1.0V is shown.
as revs decrease, the reading should drop to b/w 0 - 0.5V
At idle, 1.0V or less should be shown.
If readings are outside this range then fit a new sensor cos the one you have is f#%ked, kaput, stuffed, buggered, etc.

I don't have a wiring diagram to help you any further.

Good luck

it's the red and blue wire on an na6, so i guess most likely it's the same on an na8 . there is a very easy way to check, just get yr multimeter and find the wire in the engine bay, connect it to the multimeter. then find the wire on the ecu connect it to the mutlimeter and read the resistance . if there is very low resistance, you've found the correct wire. i did it by sticking some pins in each end of the wire and putting aligator clips on the wires and multimeter probes.

have a look at this thread for some photos and tutorial of my install

http://www.aus-cartalk.com/viewtopic.ph ... tallin+ego

the only thing i have changed since doing this write up , is that i no longer get my power from the ecu 12v. i'm taking power from the blue wire under the steering column, same place as where i'm powering my dfa from.

Yeah i had a read up on the miata forums before heading off to work, and found that it was the Red and blue wire, 2n in the plug..

The air/fuel display is working like a champ now... like a disco in the car lol...

yeah. i don't even see mine anymore, now that i'm accustomed to it. but yeah, it can be a bit strange when you first fit it. all those flashing lights.