Air Fuel Ratio Gauge Help

[classicdat]

I have just purchased a second hand AutoGauge AFR Stepper Motor gauge, no wiring diagram or anything, pictures attached.
I powered it up, red to 12v and Black to ground, nothing else connected, and it lights up and the needle goes right around.
No matter what else I do that is all that happens, grey to sensor, violet to sensor, grey to 12v, nothing changes, still full rich is displayed.

Any ideas? Not much use currently.

Confession: Is fitted to a VT Commodore, Gen 3 5.7L in to the factory sensor, bit sophisticated for a 1200 on carbs!

First shot shows the 4 wires, Grey, Violet, Black and red

[DJZ]

I'm pretty sure one of the extra wires will be for connecting to the dash lights, I'd suspect it would be the purple one.

How many wires does the oxygen sensor have and do you know which wires are which? There are a couple of different types of O2 sensor but I'd think a Holden would use a standard style one.

I'd be careful about putting 12 volts on the wires as well, most O2 sensors are only 0 - 1V unless it's a wideband sensor, I think they might be 0 - 5V?

[datsunboy]

correct....narrowband is 0-1V, wideband is 0-5V
This will surely be a narrowband gauge, and designed to just receive a 0-1V signal from the factory wired O2 sensor.

Some factory sensors are heated, some are not.....both will be narrowband

[classicdat]

Thanx Guys, yeah only connected voltage to gauge. Car is running LPG so am using the wire they took the O2 signal off for that. But connecting it doesn't matter, still reads full rich.

[datsunboy]

I think that this is the instructions for your gauge.....or very similar.

So violet to dash lights.

the White (or grey in your case) will be the sensor wire.....and should be 0-1V only.

Wire it up like that, and start the car up for 5mins, and if it doesnt change then I'd take a guess that the gauge is poked

[classicdat]

I fear you are right Dan. Thanx, but not really what I wanted to hear.

[160jsss]

you say it's running on lpg that will give you different readings ?