should i wire the air fuel ratio gauge to the o2 sensor after my cat, or the one before the cat ?

 

If its a shortband(gauge has 3 wires total,doesnt show numbers) its the 1st o2 before the cat and Its the purple with white stripe wire that you tap,

 

yea it has a black wire(ground) red(power) a white and a Green, but i think the white wire is just to turn on the back light of the gauge....while the red powers the led lights to tell if its rich or lean etc... so sounds like i wire before the cat right ?

 

yup yup

 

Wideband(shows digital readout)before the cat
Narrowband(sweeping led between lean,rich,stoich)after the cat

 

and dont forget narrow band is weaksaus and useless, unless you like light shows

 

lolz.

Never heard of wiring any AF meter after the cat.Unless you like knowing how well the cats doing

 

agreed...but some ppl love the pretty lights flashin around lol Kinda like a buddy of mine that put it on his 2.2 just so he could have a gauge on the pillar lol. It's a $15 autozone Faze one lol

Narrowbands usually work off of the first O2 sensor which is behind the cat...that's what I've always been told anyway

 

the 1st o2 is in front of the cat.So off the manifold or header.2nd is after the cat.
And they do serve a purpose.I put one on my car and I found out my car runs lean untill 5k RPM

 

How many O2 sensors do you have? I only have one and it was most definately after my cat. I had to have the second bung welded in on the dp to hook up my wideband. Are these N/A cars different and I don't know it?

 

Every car 1996 and newer has atleast 2.You have a factory one on the header/DP before the cat and one after the cat.Alot of newer fords have up to 6

 

I will have to slide my lazy butt up under there again, but I'm 99% there's no O2 sensor on my dp. Unless it's hiding somewhere on the header and I missed it, there isn't one. Of course, my car is a factory fluke/**** up. Mine has a stock 3" dp on it, so i dunno. It's goin to get a new muffler put on here soon and I'll check it then.

 

theres one there otherwise your car would run like dog ****.The computer uses the one before the cat to adjust fuel trim and the one after is to monitor the cat.
What year is your SC?

 

Tis an '07...and half the time, she does run like dog ****. Oh wait...i mean THRU dogshit. My g/f decided to drive thru the yard the other day and rolled right thru a big ol pile lol

 

07's I believe are all on the DP.Mines an 07 and I have both on the DP.one before and one after where the cat used to be(catless).I believe the SC's are the same.Im not sure never worked on a 07 LSJ.just a couple 06's.

 

if you pop the hood, and look where the downpipe is, u'll see the o2 sensor that is before the cat(s).... then look underneath the car, the other o2 is after the cat...i think all the cobalts are basically like this.... and then i think theres an o2 sensor off of the manifold itself, because they sell aftermarket ones with bungs for it, but im not sure, havent done my headers yet..

but...am i splicing the purple wire then ? with the white stripe

 

Correct

 

hmm im only seeing a white wire, black, ....... but not purple...

 

Its on the car side of the harness not the o2 sensor side.Its purple with a white stripe

 

k i figured it out lol thanks. i didnt get to drive it yet, cuz theres 2 cars blocking me in my driveway,so i only got to start it up and leave it at idle, and it just kept bouncing from lean to rich basically.. is that normal at idle ??

 

yes it will do that all the time until you floor it then it should lean over toward rich.