Could someone explain to me some A/F Gauge Stuff?

Contour Enthusiasts Group Archives

Hello,

I just purchased an Autometer A/F gauge and all I have left to do is connect the purple wire to the Red/White wire under the hood. I wanted to check things out before I made the final connection.

I have been searching the forums on people who have already done this, and it seems our cars have narrow band o2 sensors and it is better to use a wide band. I currently have all the cats in place on my car, and I am willing to put in a wide band to get a better measurement.

So, I have a few questions which I havent seemed to find answers by searching the forums:

What is the difference between wide and narrow band? Is it the output voltage range higher or is there something else?

Can I replace a stock upstream O2 sensor with a Wide-Band? Or will this freak out the computer? If I can do this, what make/model do I purchase?

I would assume I want to get a reading off an upstream O2 sensor so this way the cats dont interefere with the true A/F reading.

Thanks for your input, and forgive my ignorance!

Originally posted by hsoverma:
Hello,

I just purchased an Autometer A/F gauge and all I have left to do is connect the purple wire to the Red/White wire under the hood. I wanted to check things out before I made the final connection.

I have been searching the forums on people who have already done this, and it seems our cars have narrow band o2 sensors and it is better to use a wide band. I currently have all the cats in place on my car, and I am willing to put in a wide band to get a better measurement.

So, I have a few questions which I havent seemed to find answers by searching the forums:

What is the difference between wide and narrow band? Is it the output voltage range higher or is there something else?

Can I replace a stock upstream O2 sensor with a Wide-Band? Or will this freak out the computer? If I can do this, what make/model do I purchase?

I would assume I want to get a reading off an upstream O2 sensor so this way the cats dont interefere with the true A/F reading.

Thanks for your input, and forgive my ignorance!

are you running FI? (nitrous, turbo/supercharger)

you want to mount the wideband right at the joint of the y-pipe before the flex pipe and main cat. This is granted you dont have pre-cats.

Most people use a wideband because with a wideband, if your car goes lean and lets say, you need to stop spraying nitrous it will tell you pretty much right away. By the time a narrowband shows you that you are running lean it is to late.

Also a wideband will tell you your exact A/F ratio.

You haven't mentioned your INTENTIONS for having a wide-band O2 sensor, other than "getting a better reading".

Were you asking if placing a wideband in the narrowbands spot will somehow help the PCM to make better choices?

Unless YOU are going to view the information, and adjust your driving based on such, the wideband wouldn't do anything *helpful* that a narrowband couldn't.

The PCM can't utilize the wideband to any scope that it will change your fuel strategy for any benefit. Also, unless you are running some sort of FI, or nitrous application, a N/A platform will not NORMALLY see a USE for a wideband, especially if you are on the stock tune, with stock components.

Ok, Thanks for the replies. I am running N/A with no nitrous, and like I said in the beginning, all the cats are still in place, including the cats in the headers and the main cat after the y-pipe. Everything is, for the most part, stock including the stock tune.

I am mostly installing this for cosmetic reasons, but I am still curious as to how all of this works.

I still dont understand the difference between wide-band and narrow-band.... does 'band' refer to the voltage output range, the response time, or the range of oxygen quantities?

IF it is true what you say about the nitrous, where the stock unit is not "fast" enough to keep up with actual changes, then the band must refer to the bandwidth(or response time) of the output... meaning the voltage output lags quite a bit behind the actual levels in the exhaust. The slow bandwidth (narrow-band) has inherent filtering which sort of averages out (overdamps) the voltage output. Is this a correct statement?

Thanks!

Originally posted by hsoverma:
Ok, Thanks for the replies. I am running N/A with no nitrous, and like I said in the beginning, all the cats are still in place, including the cats in the headers and the main cat after the y-pipe. Everything is, for the most part, stock including the stock tune.

I am mostly installing this for cosmetic reasons, but I am still curious as to how all of this works.

I still dont understand the difference between wide-band and narrow-band.... does 'band' refer to the voltage output range, the response time, or the range of oxygen quantities?

IF it is true what you say about the nitrous, where the stock unit is not "fast" enough to keep up with actual changes, then the band must refer to the bandwidth(or response time) of the output... meaning the voltage output lags quite a bit behind the actual levels in the exhaust. The slow bandwidth (narrow-band) has inherent filtering which sort of averages out (overdamps) the voltage output. Is this a correct statement?

Thanks!

Just install some LED's in the dash and make them light up in random orders, you will save yourself some money and still look like a ricer in the end.

Tourique,

I am so sorry I am so underneath you and so inferior to you. You must be a CEG God, and I am fortunate to even have you write to me or even read my post. Thanks for being so helpful. Your superior intellect and skills are too high for me to understand. We all should all bow down to you because we dont do things the way you want to do them.

Please, all of CEG, bow down.

wideband sensors provide a linear reading while narrowband sensors jump all over the place. So with a a/f gauge hooked up to a narrowband you are just going to get lights jumping back and forth from rich to lean.
If you want a more accurate indication of your a/f ratio you can spend $300+ and get a wideband system or you can send you gauge to someone that will chage the voltage your gauge responds too for a more accurate reading. I don't remember the place off the top of my head but i will search for it

here is how they work if you want to know

edit:
Thread covering A/F guages

Originally posted by hsoverma:
Originally posted by Tourige:

Originally posted by hsoverma:
I am mostly installing this for cosmetic reasons, but I am still curious as to how all of this works.

Just install some LED's in the dash and make them light up in random orders, you will save yourself some money and still look like a ricer in the end.

Tourique,

I am so sorry I am so underneath you and so inferior to you. You must be a CEG God, and I am fortunate to even have you write to me or even read my post. Thanks for being so helpful. Your superior intellect and skills are too high for me to understand. We all should all bow down to you because we dont do things the way you want to do them.

Please, all of CEG, bow down.

He was being serious!

All mine does is go back and forth, back and forth, back and forth, back and forth, etc.

About all it does help me with is if the car is constantly lean due to a vacuum leak... then it's red/yellow/red/red/red/yellow/red/yellow/red or just constant red.

Plus it doesn't light up just a single LED, it's like 5 leds swinging back and forth. Kinda like if your tach needle was 500RPM wide...

Originally posted by hsoverma:
Tourique,

I am so sorry I am so underneath you and so inferior to you. You must be a CEG God, and I am fortunate to even have you write to me or even read my post. Thanks for being so helpful. Your superior intellect and skills are too high for me to understand. We all should all bow down to you because we dont do things the way you want to do them.

Please, all of CEG, bow down.

Im sorry, i just dont see the point of wasting money on useless guages that wont do anything for your car.

If you really want; Take that 300 bucks you were going to put into guages, take the 100 bucks for the lotek guage pod, and get a damn dyno tune.

Oh stfu the both of you. bottom line is the A/f gauge is worthless unless its a wideband (could have just said that tourige). I own one myself, and until I can afford to buy a wideband, it will be filling a gauge hole in my dash. Besides...blinking lights distract me from noticing fart cans on cars next to me, forcing me to drive with road rage

Here is my best shot at "explaining" why a narrow and wideband are different without any science to complicate the issue.

Wideband has a voltage range from ~approx 0-2volts. You can search for the voltage scale.

The regular narrow sensor works form 0-1volt and they aren't calibrated so that you can read them directly. That is because the stoichiometric A/F ratio is such a narrow portion of the sensor voltage that the pcm can't read with enough resolution from it to determine the actual stoiciometric A/F, even if it were constant. The way around it is to oscillate the A/F from rich-to-lean really fast so that the O2 sensor voltage goes above and below the stoichiometric point, and then the pcm will figure out the average from that.

Think about balancing a broom stick straight up, it will not stay so it starts to fall left you give it a little nudge and it goes over the top and starts to fall right then you give it a little nudge back. You can't determine the exact point that will balance the broom stick upright as it is so small so you just keep tipping it back and forth very close to the apex.
This is exactly what the pcm does with the air fuel ratio only it is changing the injector pulsewidth to make it rich-lean and try to "balance" the sensor at the stoichiometric point.

Widebands don't work that way, they output a constant voltage based on amount of oxygen in the exhaust. They cost a lot more and need special electronics to run the heater and read the results in a format you can use. They are also much more sensitive to water in the exhaust and under/overtemp. The narrow bands are cheaper and more durable, but give them time and they may improve wideband O2 technology to the point where they will be cheap enough for regular cars.