Celica Forums General Discussion Exterior air fuel ratio gauge installation ?

how did you connect your Air/fuel ratio gauge ???

On the cpu or directly on the O2 sensor ????

pics of it would be very apreciate !!!

My friend is gonna help me but it's a civic guy... so if you can show me the right way... it will be very nice !

thanks in advance for your help !!

You need to tap into the wire coming from the oxygen sensor. It's a blue wire underneath the carpet on the passenger side. You should be able to see the wires running along the center console and going underneath the chassis through a gromet. I hope this helps

Yea it's the blue wire with the other 3 wires coming down from the passenger side foot well, where the center console runs.

I can confirm this, I just installed mine the other day. tap the sensor closer to the front of the car for best results.

Works as expected, but so many people complain about these things being inaccurate; they actually work pretty good when it comes to evaluating your A/F ratio at a glance. You just need to know how to read them correctly.

When cruising, the gauge will sweep from the lean region to rich, this is because the ECU is constantly adjusting the A/F ratio through injector pulses. in reality, you get the whole rich/lean/rich/lean thing because this is how most modern cars will generate a stoich mix using this pulsing method.

Simply make a mental note of the low and high points of the sweep, the point closest to the center of the sweep is your actual A/F ratio.

take your foot off the gas, and the gauge will go dark, you aren't leaning out so much as you are cutting the fuel from the engine (hence, o2 sensor gets no reading)

under WOT and lift, the car will go in the range of rich to stoichometric, same happens when I slow down under certain conditions (remember, I drive an automatic, this rich condition under braking may be different on a manual)

the more throttle you give, the quicker and broader the sweep gets, at idle, the sweep will be very slow.

the colder the engine is, the richer the mixture will be.

all in all, it's a good diagnostic tool, and will help recognize fuel system problems. incidentally, they make A/F gauges that aproximate the ratio by themselves (IE, no confusing sweeping readout) Some actually show the A/F ratio numerically. However these a/f gauges cost a bit more.

as for wideband: great for tuning a car on a dyno, crappy for daily driving.



BTW, to make the gauge readings as accurate as possible, be sure to connect the gauge's ground wire to an ENGINE ground point, I chose the one next to the Intake manifold (where the factory ground wire is attached with a 12mm bolt)

overall, connection is simple:

Signal wire goes to the front O2 signal wire blue

Ground wire goes to ground point on the cylinder head. There is a black ground wire held on by a 12mm bolt

Power wire goes to a powe souce that is on when the car is turned on, You can tap the red wire that clips on behind the cigarette lighter socket, or to a circuit in the fusebox that is on when the car is running (avoid ECU, ABS, or SRS fuses!) Try the clock or radio fuse

the illumination wire goes to a lead that is powered up when the lights are on, I tapped the little bulb that is next to the cig lighter (it illuminates the ashtray and lighter socket when lights are on) I tapped the green[/color] wire. You can also tap the dimmer knob, side marker, etc, just make sure you clip to the positive lead if possible.

^^^ Best explanation I've read, well put. This is completely accurate. And it IS the light blue wire coming from you're BEFORE CAT O2 sensor.

Yes did mine too. use a vampire clip to attack to the blue wire.

Just be careful with those vampie clips, make sure the metal tab goes all the way down into the locked position when crimping.

I used 1 posi-lock splicer, two vampire clips (for power and illumination) and a couple heat shrink splicers to extend the wiring harness. I need a bigger eyelet for my ground lead; for now it's stripped about 1/2 inch and fastened between the eyelet on the engine ground lead and the head.

I will be adding an appropriate eyelet for the ground, and looming the harnesses this weekend sometime (the wires have only been zip-tied out of the way for now).

one last tip, if your gauges are indiglow, and have a small, external power convertor chip (actually a small transformer) use a small piece of gray 3M double sided trim tape to attach it to the inside of the gauge pod. be sure to put it on the dull, smooth side, and not the side with the glossy epoxy sealing the unit.

thanks all !!!

just to be sure...

i dont quite understand, i get the negitive wire and attach that to the negative on the car, postive to the postive and the a/f ratio wire to the wire i circled in green? and if so, how does it detirmine how much fuel is being used?

and what is the wire circled in blue for?

I thought it's the wire that circled in blue that you have to connect to the o2 sensor of the a/f gauge. I don't think it's the wire that is circled in the green. I just connected mine, and connected to the one blue wire circled in blue.

i connected my wire to where it says new wire in the pic,gauge turned on,but now car wont start and Ive got a CEL that wont go out...any clues..?

I found this pics on an other celica site... not mine...

so we should connect it on the old wire (on the pics)

its the one circled in blue

Ill post a vid of how the gauge jumps around

VIDEO - here ya go, hope this helps

damm I bow down to you bro, you know ur shit, this is 100% accurate, watch my video and see for yourself...

so then whats the one circled in green?