O2 Sensor - Signal wire ?? R33

[B-Man]

Hi,

R33 GTS-T 1995

Which is the signal wire on the ECU side of the o2 sensor ?? Either at the O2 sensor (after the plug/converter) OR pinout at the ECU ???

Am installing a ricey A/F ratio guage and need to tap into the OS sensor signal wire.

Thanks in advance !

[rs73]

Attached is a ECU wiring diagram for R33 from S-AFC manual. Hope it's clear enough for you. Just be careful and count the right wires on your ECU.

BTW. What brand of A/F meter you're installing? What's it look like, cool gauges? Is it pretty accurate? I found the one on Apexi TT was not accurate.

[A31_Cefiro]

Hi,

From what I've read and been told most A/F gauges aren't always accurate to start with but can be adjusted when tuning for more accuracy....

[B-Man]

Thanks !!

It's an Autometer (doesn't display actual ratios - but ranges - ie lean , rich, stoich). I too have heard that they are inaccurate - May be the O2 sensor tho - apparently there a a couple of types- one being more accurate than the other.

When I get it on, I'll compare to the lambda?? probe they shove up the zorst when it is on the dyno.

Cheers,

BTW - looks like pin 29 on the ECU connector OR the Centre (clear) cable off the O2 sensor itself is the signal cable.

Can anyone confirm ??

[A31_Cefiro]

Yep, compare it and let us know what you find.

The A/F meter just reads voltage ranges. There was an article on autospeed about it when they built the jaycar kit.

To work out which wire is the signal wire on the O2 sensor I've been told you use a digital (not analogue) multimeter on the wire and whichever wire fluctuates is the wire you need to connect it to.

The S-AFC instructions list the air flow signal pin in drawing N-4A for an R33 with RB25DET made before 96. It does not list a pin number though.

S-AFC wiring diagram can be found at:

http://www.apexi-usa.com/productdocumentat...s_safc_wire.pdf

[kjb_r33]

i think your ion ofr a bit of an expensive mistake, thats if your A/F meter cost much....

Most oxygen sensors put out around .2 to .8 of a volt, depending on if its running rich or lean.

From what i can see, and i tested this on an oscilliscope, the oxygen sensor on my r33 switches from 0 to battery voltage, around 14 volts. It has 3 wires, an earth, a voltage supply and a signal wire.

i would check this out before i wired the A/F meter up.