If I want to connect a Defi gauge to read the air fuel ratio being reported by the existing 02 sensors (not install a new/dedicated 02 sensor), where would I plug in the gauge? The back of the ECU? Does the included wiring harness make this easier?

 

We normally connect it at the ECU. You'll have to strip some of the wires near the ECU.

 

The DEFI D-Gauge A/F gauge is a narrow band gauge. Basically you'll want to splice the wire off either rear 02 sensor and not the primary WB02 units (or off the ECU's narrow band input) This gauge is good for a general indication of you A/F, but the response and range would not be suitable for tuning.

Cheers,

Gary
Gruppe-S

 

A narrow band O2 gauge is about as useful as a bumper temp gauge. Get a wideband uego or don't bother at all. A narrow band O2 does NOT measure fuel mixtures. All it does is tell you which side of Stoic the mixture is at. It will constantly flicker between rich and lean and tell you nothing.

 

Thanks for the feedback, Steve. Right now that is all I am looking for.

 

wideband all the way, lol

 

Which cable specifically has the air fuel signal?

 

it will give you a pretty close reading under WOT, which is useful to see if you are running rich or lean then. WOT is where the danger would come in most all cases.

 

So for the Defi-D gauge all you do is splice into one of the rear o2 sensors? Other than power of course?

 

right under the maf sensor is a connector. it is for one of the rear o2 sensors. the gray wire is the one you want to tap into for your signal. look for the connector that has 2 whites, one black, and one gray wire coming out of it. true the narrow band does bounce back and forth, but as you put your foot into the gas a little it steadies out and will give a reading.

 

Yup, this is what the guys at XAT Tuning did for me. They found power in the A-pillar, which also provides gauge illumination when you turn the lights on. They connected the sensor wire to the O2 sensor, and voila!! I posted pics in this thread:

https://my350z.com/forum/engine-and-drivetrain/121829-air-fuel-gauge-installed-with-pics.html