Autometer Air/Fuel Ratio Gauge

[DonaldSeriesII]

I installed a new air/fuel gauge in my car. The instructions only show for a 1 wire o2 sensor but the sensor on a 3800 II has 4! Now i did the logical choice, the wire from the gauge was purple and there was a purple wire coming from the sensor itself so i spliced it in. The gauge works but it looks like it is erratic and i'm not sure if it is working properly. If anyone has every put one one please tell me if I installed it the right way and if I am getting a proper reading. Thanx! :rolleyes:

[Jerriko]

Yes, erratic is best. Every bar on the gauge represents .1 of a volt (or .05 V, I can't remember). The O2 sensor always sends out a voltage directly related to the amount of air in the exhaust. It should be operating between .2 to .9 volts since the computer is always correcting the air/fuel mixture. Best thing about the air/fuel gauge is that when your O2 sensor goes dead, you will know it.

[malice10985]

I put mine on the 02 sensor on the left cylinder bank. I didn't want to put it on the o2 sensor aft of the catalytic converter, because that could cause it to be inaccurate.

I only get a reading from 3 cylinders since it is on the left bank, but the reading is pure exhaust, so it should be pretty accurate.

I use the peak of the gauge fluctuations for practical purposes. In part throttle ops, it is very erratic, but the highest light seems to be about what the mixture is.

It stops fluctuating at full throttle and gives a constant reading. It is most useful at full throttle.

[y87inside]

Id want to run mine post cat. It would still give you rich/lean conditions right? Without the eratic readings since the post cat O2 dosent change nearly as much as pre cat O2's. This is just me though.

[Jerriko]

I would run it to one of the O2 sensors in front of the cats since they generate air (and sometimes is supplied air) by design and this would mess up the reading on the air/fuel gauge. It would almost always read lean.

[Ted]

My friend made a circuit to switch from the left bank and the right bank to check both sides. I'd image it is a pretty simple thing to do.

[cammed3800]

what if you dont have a cat? where is the best place for the af gauge? doesnt someone sell a harness you can use so you dont have to hack up a 50.00 sensor?