Installing Autometer Air/Fuel gauge

[tmnismo91]

The vehicle is a '91 Maxima w/ the VG30E motor. I am trying to install my air/fuel ratio gauge and can't determine which is the hot wire on the 02 sensor harness. There are three wires (green, white, and black). When I connect to the green wire, start the car, the gauge does nothing. When connected to the white wire, start the car, the gauge goes berserk. The readout doesn't seem acurate. Also, some guys connect down by the ecu whereas I connected to the harness in the engine bay. Are there any advantages/disadvantages to this? And help me find the hot wire. Please advise.

-Sean

[NISTECH]

First of all Air fuel gauges would likely connect to the signal wire of the O2 which is the white wire, then the gauge should get its power and ground for illumination from a power source and body ground. The reason for hooking up inside the car versus out side is to eliminte electrical interfearance from the ignition system.

When a car fist fires up the O2 reading is inaccurate till the O2 warms up. The 3 wires on the o2 are not just for o2 signal but one of the wires supplies 12volts power to the O2 heater , if you hook up to that wire you will possibly fry your A/f gauge as it is only designed to see up to 1 volt.

[tmnismo91]

I don't see how you can fry LEDS

[D Money]

u definatley can, when that happens they pop