Air/Fuel gauge freakin out, cuz i wired it wrong?? Options

[Redline08]

So i just hooked up an air/fuel gauge to the O2 sensor coming right off the headers. Im guessin this wasnt the best place to wire it because it jumps back and forth from lean to rich constantly unless i go WOT then it just shoots into rich and stays there until i let off.

Wheres the best place to wire it? prolly off the ECU?...

[Kwanza26]

So i just hooked up an air/fuel gauge to the O2 sensor coming right off the headers. Im guessin this wasnt the best place to wire it because it jumps back and forth from lean to rich constantly unless i go WOT then it just shoots into rich and stays there until i let off.

Wheres the best place to wire it? prolly off the ECU?...

On a basic narrowband O2 sensor... that's typically what it'll do.

[Redline08]

it typically bounces back and forth like a retard?

[Jeunesse]

"One thing to make sure of though is when you connect the o2 signal wire, tap into the main harness wire, not the o2 sensor wire. The o2 sensor wire has a small hole in it so that it can take a reading of the outside air to compair it to the amount of air in the exhaust, if you tap into that wire, your o2 will give off a false reading and it will screw up your A/F ratio. " - Valo666
"And on Deceleration... Your car is automatic, so when you are on the brakes, the torque converter unlocks, and the idle valve bumps up the idle, thus, your engine is no longer in decel mode. When your engine is at a higher RPM with no throttle and no brake, it is in decel mode, aka deceleration fuel cut. During this time, your injectors are fully shut off (zero duty cycle), so your O2 sensor is not registering any fuel in the exhaust stream. What you are seeing is absolutely normal.
Narrowband AFR gauges are also a universal item, so any differences with O2 sensors (ie: GM, Toyota, Honda, etc) will react differently with the gauge.
It's nice to see what your engine is doing, but the nature of this gauge is very inconsistent so don't worry about it too much. " - Tony_the_Tiger


This post has been edited by Jeunesse: Jan 20, 2008 - 3:11 PM

[Redline08]

damn nice response lol. I tapped into the wire after the connector, not the wire coming right off the sensor so im guessin im all good.

Thanks!

[playr158]

all that is good for is a cool light show.

[lagos]

it typically bounces back and forth like a retard?

thats how they work. the bouncing is meant to show you that the car is running in closed loop mode and that your o2 is working correctly.

[stetsonaw]

my autometer phantom does the same thing, so annoying.

[wrathc5525]

according to my teacher it is supposed to do that because the pcm is constantly trying to keep a stoichiometric air to fuel ratio of 14.7-1. so the pcm use's the o2 sensor's reading to see how much air is in the exhaust system. if there is not a lot then the system is rich and then the pcm narrow's pwm of the fuel injector solenoids so its sprays less fuel which means more air in the exhaust which makes it go lean. so it is always changing to compensate for a 14.7-1 ratio

[Bitter]

sounds like you thought you would be seeing a wideband output which will still bounce around but not as much.

[6G96GT]

so why wouldn't you just go with a wideband kit and then tune it correctly for the proper A/F?

[6strngs]

so why wouldn't you just go with a wideband kit and then tune it correctly for the proper A/F?

cause widebands cost about $200+ more than just a narrowband. but it definately is the only way to get an accurate reading of your A/F ratio.