Air Fuel Gauge Installation on 1JZ-GTE

**Danners** · 06-05-2007, 10:51 AM

Hi Guys,

I bought an autometer air/fuel ratio gauge yesterday and have installed it. My question is this:

The o2 sensor on the 1J has three wires coming out of it, two black and one blue. Without anything to go on but the document that came with the gauge I could see that one was a heater wire, one was the signal wire, and the other was a ground (i think) but i'm not sure which was which so I hooked the signal wire from the gauge into the blue wire coming from the o2 sensor... the logic behind this was that it was a different colour to the other two

Is this the correct wire? If it is, this brings me on to my next question...

I start the car this morning, cold... the gauge reads lean until 2 or 3 minutes later the car warms up it goes stoich then varies back and forth in that vicinity. If the gauge is indeed reading correctly, why is it so lean for so long? Is this normal?

If anyone has any suggestions, i'm all ears!

Thank you!

**BeRad** · 06-05-2007, 10:52 AM

Becuase the sensor is heating up, yes this is normal

An o2 sensor cannot read accureatly when the sensor is cold with the engine slowly heating up the sensor will heat up that bit more, that a/f guage will not be accuarate so i woudlnt worry to much about it those guages are nothing really more than something fancy on the dash, for it to be accurate you need to buy a wideband sensor which is a 5 wire sensor, yours would be narrowband which only really reads lean or rich.

**Danners** · 07-05-2007, 10:46 AM

Thanks for the reply!

I'm still not sure if i've hooked the gauges sensor wire up to the correct o2 sensor wire... but the thing is "working" although it jumps around all over the place while i'm driving. If i mash the accelerator it reads as rich as it can go, but when i let my foot off it reads as lean as it can go.

Is this safe for the engine? I would've thought that the o2 sensor, and computer would be changing the fuel mixture under deceleration so that it remained stoich.

**BeRad** · 07-05-2007, 11:27 AM

This is exactly how a narrowband sensor will act connected to a a/f guage, as i said above they are realy only good for telling you weather its rich or lean, not in between, thats what a wideband 5 wire sensoe is for. When you take your foot off the accelerator when the car is moving the ecu turns the injectors off to save fuel etc etc, thats why when you back off it says lean. and when you put your foot down the sensor is not accurate enough to give in betweens to it just shows rich. So overall dont listen to what the guage is telling you because its not accurate, if you want it to show accurate readings you need to upgrade sensors, or add a wideband in for the guage.