hi all
i am a little confused about O2 sensor, most aftermarket sensors on it wiring diagram shows 4 wires, 2 for the heater (no doubt, no matter how you connect those, heater will work) and 2 for the sensor (1 to the positive and 1 to ground) these 2 got to PCM, i was checking my car diagram and the sensor wires do not handle positive and negative, it says hi signal and low signal as it shows
http://i184.photobucket.com/albums/x316/felipeurbalejo/untitled.jpg
hope pic is good enough :(
should i connect the positive wire from the O2 sensor to the Hi signal wire from the car wires and the ground to the Low signal?
any help is always appreciated
thanks in advance

ok this is a best pic
http://i184.photobucket.com/albums/x316/felipeurbalejo/SENSOR-O2.jpg
i forgot, it's for my 96 camaro 3.8 v6
thanks

That would be my guess, but you should find out for sure before you run juice through it. Is this the stock EFI controller? Why isn't this just a plug-and-go operation?

it is not the stock controller, is an aftermarket sensor and has no brand engraved on the body.

Looks like HI is signal, and LO is ground:



http://www.gearchatter.com/viewpost14316.php

http://67-72chevytrucks.com/vboard/showthread.php?p=2552194


http://www.gearchatter.com/si/605018.png

thanks for help, sensor was connected yesterday and hope to have more miles/gal. let's see what happens. :)

I do not play with EFI, but I was under the impression the ground was the threaded plug of the sensor, and the high is a 4.7 volt signal and the low is a 1.5 volt signal: not positive and ground. The wiring should have two parallel circuits to the sensors as I under stand it.

The sensor generates the current, you don't route power to it (other than for the heater). The amount of oxygen is determined by a difference in the number of oxygen ions in the exhaust gas as compared to the outside air (if you are familiar with the concept of a Wheatstone Bridge, it behaves in a similar manner). The ionization potential allows current to flow (at least at very low levels which is fine for a digital circuit). Putting full battery potenial on that circuit could be potentially hazardous to the ECU.

Big Dave

I do not play with EFI, but I was under the impression the ground was the threaded plug of the sensor, and the high is a 4.7 volt signal and the low is a 1.5 volt signal: not positive and ground. The wiring should have two parallel circuits to the sensors as I under stand it.

The sensor generates the current, you don't route power to it (other than for the heater). The amount of oxygen is determined by a difference in the number of oxygen ions in the exhaust gas as compared to the outside air (if you are familiar with the concept of a Wheatstone Bridge, it behaves in a similar manner). The ionization potential allows current to flow (at least at very low levels which is fine for a digital circuit). Putting full battery potenial on that circuit could be potentially hazardous to the ECU.

Big Dave

i am agree with you dave:yes: i know hi and low signal it's not same than positive and negative.

this is what i've done, the aftermarket sensor has 4 wires, 2 whites, 1 black and 1 gray, if i am right; if not please advise me, 2 whites are for the heater and no matter how you connect it, it will work.
i read that on that sensors black wire is the reading wire and gray is a ground. then i connected my hi signal wire to black and gray to my low signal, at this time i am feeling a little worried about gray wire. perhaps this sensor is not adjustable to the ecm.
by the way i questioned to a frind what it could be the worst case scenario if i made a mistake connecting wires and told me i will get lower miles/gal.
maybe this diagram could help
i downloaded from the repair manual
http://i184.photobucket.com/albums/x316/felipeurbalejo/88144gc3L.gif

i am agree with you dave:yes: i know hi and low signal it's not same than positive and negative.

this is what i've done, the aftermarket sensor has 4 wires, 2 whites, 1 black and 1 gray, if i am right; if not please advise me, 2 whites are for the heater and no matter how you connect it, it will work.
i read that on that sensors black wire is the reading wire and gray is a ground. then i connected my hi signal wire to black and gray to my low signal, at this time i am feeling a little worried about gray wire. perhaps this sensor is not adjustable to the ecm.
by the way i questioned to a frind what it could be the worst case scenario if i made a mistake connecting wires and told me i will get lower miles/gal.
maybe this diagram could help
i downloaded from the repair manual
http://i184.photobucket.com/albums/x316/felipeurbalejo/88144gc3L.gif

This makes more sense to me. The sensor wires are not positive or ground they are conductors going to the ECU. The power to ground for the heater is correct also. Please note that it takes 10 Amps to power the oxygen sensor, or 10% of a modern car's ignition load.

I do not play with EFI, but I was under the impression the ground was the threaded plug of the sensor,

Depends on the sensor...

Some are made that way, but that requires that the exhaust system be solidly grounded in order for it to work well. Even at that, it's a tough environment in which to get good contact that way.

From what I've read, there are 1, 2, 3, and 4 wire sensors. The one wire style has no heater, and the signal is referenced through the case. Two wire ones don't have a heater, but the signal is referenced through the second wire. The 3 wire ones have a heater (2 of the wires) and the signal is referenced through the case, and the 4 wire ones are 2 wires for heater, 2 wires for sensor.