Air Fuel Gauge


First off, I got this thing for free and yes I know they're shit compared to wideband :lol: (autometer $60 A/F gauge). I want to at least hook it up the best way so that it gives a decent reading. The other thing I'm worried about it it changing the voltage and thus effecting the way the ECU controls the A/F ratio. So I have a few ?'s

1. Which o2 would be best to tap into?
2. Will tapping either o2 effect the ECU readings at all?
3. Would getting a 3rd o2 be better/safer? If so would one of those Bosch o2 be workable?

I would rather not have to drill/weld/wire a 3rd narrow band but if neccissary I guess I'll do it. Thanks!


Yea I was considering trying that too, but I've heard that the response is much slower from that location...
i allways run them to the ecu what does response mater any ways you wont see it. (testing your reaction to delay) hook a 6 ft wire to neg bat terminal and a 6 ft wire to pos. now atach one to toe and touch the other to our tongue. now step two lengthen each wire by 50 ft and repeat you shoudnt get shocked due to the fact that the wire is longer and you should be able to pull it away first. since it is 0.0000001 sec diffrence.


I understand basic electronic physics fine thanks.

I've read on this forum that tapping by the ECU provides a noticible delay, whereas tapping the o2 leads in the engine bay yield an instantaneous readout. It really shouldn't give a delay from a logical stand point, but I'm just going by what I've heard.

I'm much more concerned with altering the signal to the ECU...


Senior Member
I have an autometer air fuel ratio gauge , i hooked up to the green(i think its green) try them all until the gauge responds good. three wire coming off my 02 sensor on my header. i just ran a wire along my wire harness through the fire wall and attached it with a wire splice. i found that wire responded great. It still works great i use it every day and it always works good with that wire. the other wires gave me a bad signal and weren't accurate. B)