View Full Version : A/f Gauge Question

05-03-2005, 01:29 PM
Just Wondering Which Wire Coming Out Of The O2 Sensor Is The Signal Wire To Hook My Gauge To? Cant Find Any Of My Manuals, So I Figured I'd Give Ya'll A Shout

Scott Long
05-03-2005, 04:27 PM
I got the schematic and where the O2 harness is under the hood on its way to the EEC I tapped into the signal wire. It's been about 2 years so I have no idea anymore what color it is. I wouldn't try to tap into the 02 sensors harness, tap into the one under the hood. You don't want to cut the wires that come attached to your 02.

05-03-2005, 04:37 PM
My Searches Finally Came Up W/ The Answer I Was Looking For. Thanks For The Info. Im Tapping Into The Wires At The Pcm So That I Dont Have To Go Thru The Firewall At All.

David Neibert
05-03-2005, 11:41 PM
Enjoy the Lightshow, because the info you get from those gauges is only useful to impress teenage boy racers and amuse yourself at long stoplights.


05-03-2005, 11:44 PM
i just used a volt meter and i like it i think it was the black wire at the 02 sensor on my 89 , i can tell it goes into open loop around 4 pounds of boost

05-04-2005, 12:31 PM
is there anything you can hook up to actually get actual readings then?

Joisey Jim
05-04-2005, 12:38 PM
I believe you have to use a broad band O2 sensor (expensive) & install it in a separate bung in the exhaust. But if you can find a volt meter that spans from 0 to 1v it would give you a better indication of what's going on, than those available air/fuel gauges.

05-04-2005, 01:01 PM
Bottom line is, a narrow band sensor will not give you accurate readings. Basically...buying an autometer gauge or hooking up a volt meter is just a waste of time and money and will lead you in the wrong dirrection. The only true way to monitor a/f is by EGT or with a wideband a/f sensor and kit.

I purchased my kit from PLX and it was worth every penny. I got the extra wireless data logging feature and spent about $500. However they do sell basic kits with a display for around $320. IMO thats a steal....

But any kit that uses your stock sensor or taps into the stock signal is worthless. A good kit should include a wideband sensor, and a brain. The sensor is a 5 wire sensor, and range in prices from $80-$200. The majority of the money spend is on the brain which takes the signal and makes it into something readable and understandable.

Good luck on your choices man, but I'd spend your money on a useful gauge such as oil pressure or water temp and ditch that gauge you just bought. Its going to blink like crazy, flash, run up and down, and just be an eye-sore. I'd sell it to some ricer.....but everything is just my two cents......