A/F Guage

[Pyrthian]

with the narrow band O2 sensor, when you put in a Air/Fuel guage, you end up with a aguage that slams back & forth from rich to lean. has anyone ever come up with a cicuit/filter to average these out, so its a more useable guage? would just a small capacitor in line do it?
not a electronics guy, but whenever someone tries to smooth something out, they seem to always throw a capacitor on....or is it a coil? I dunno...maybe both?

[whipped]

try this:



R=100k, C=10uF. Make sure to match + with + on the O2 and Cap.

(circle/line squiggley is the o2 sensor, Vout is to your gauge)

[donk_316]

or spend the 250 bucks and get a wideband 02 and controller to run your gauge.


innovate lm1 is a good one. or is it lc1? cant remember

[p8ntman442]

what ryan posted will basically feed your meter with a voltage. The big OHM resistor makes for low current and slow charging of the capacitor. The voltaage is coming from the positive side of the capacitor. Its like reading your o2 sensor through molases. It may work by feeding your gauge, but whats it telling you, that you can get an inacurate and sluggish signal from your o2 sensor? I doubt if you did get it to work it would give you acurate enough data to do anything but make your gauge look like its working.

I aplaud ryan for not just saying go spend $$$ but Unfortunalty I dont think it will work.

Give me a little more information and I may be able to come up with a circuit. What is the output voltage of your o2 sensor from top to bottom of the range, and what is the input voltage of your sensor from swing to swing.

Its very possible and may be cheap to build.

[donk_316]

ok but i think you are all missing the big picture...


the narrow band is all obver the map because it is INNACURATE...

so filtering the innacuracy is going to amount to "flashing lights on the dash"

[p8ntman442]

I wasnt aware they were that inacurate, what if you stole one off a 2006 at the JY? A heated one, can you get acuracy from them?

[donk_316]

no. hence the name "narrow"band... you need a "wide" band to get a decent resolution

[whipped]

They're accurate.

But only at 14.7:1 AFR. They can tell you if it's leaner or richer than 14.7:1, but that's about it. You can extrapolate some useful information from them, you might even be able to guesstimate the AFR.

[donk_316]

well i sure as h3llz0r wouldnt trust it to tune with...

[emod19]

It's normal for the o2 to read this way. It's called crosscounting. When the engine is running in closed loop, the ecm does this to adjust the mixture and keep the catalytic converter operating properly. When the engine is operating in open loop (wide open throttle) the ecm uses a programmed value for the mixture, not the o2 sensor. In open loop (wot) the gauge should stabilize and read on the rich side.

Steve

[Pyrthian]

They're accurate.

But only at 14.7:1 AFR. They can tell you if it's leaner or richer than 14.7:1, but that's about it. You can extrapolate some useful information from them, you might even be able to guesstimate the AFR.

right - did some more looking into this after I started this.
while averageing will help in making it a less jumpy guage, it doesnt help any in trying to do anything other than to see 14.7:1. and thats the ideal number for milage/emmisions, not power.

[The Dark Side of Will]

With enough zero-crossings to average, it can be accurate. That's the whole idea behind long term fuel trim algorithms implemented by EVERY manufacturer in the market.

[p8ntman442]

With enough zero-crossings to average, it can be accurate. That's the whole idea behind long term fuel trim algorithms implemented by EVERY manufacturer in the market.

Probalbly very true, but that does not change anything. When you say zero crossings, is zero at 14.7, because there should be no negative voltage from the o2 sensor obviously.

either way, it dosent help the gauge issue.

[The Dark Side of Will]

"zero" = 14.7:1... middle of the range... ~.450V

[Pyrthian]

yes, the O2 sensor is not a switch. with 0.5 - 1 sec averageing, you should be able to get reasonable use out of the standard O2 sensor & A/F guage.

[Fierocious]

+1 for wideband.
The guages is pretty gay. I have one in my rx7 and i hate it. It just dances around and flashes lights.

[cactus bastard]

How hard could it be to build a simple controller to use a wideband sensor though? Data logging may be another issue, but if you just want a gauge for your dash it should be pretty simple. My understanding was that their output was pretty simplistic - nearly linear. You can get new wideband sensors for around sixty bucks, why do the controllers always cost in the hundreds?

[TurboGT]

Cheap Afr Guage?
hi i have been toying with this idea with mad professor from here.
i have an LC-1 and want an afr guage, however my options are:
i can either spend a silly amount on an xd1 or spend alot less on some cheap budget guage that looks rubbish.
so we were chattingand came up with the idea of setting one of the LC-1 outputs to read
1v @10:1 afr
and
2v @ 20:1 afr
then wire in a Voltmeter that reads 1-2v
this would mean at 1.500V the Afr would be 15:1
etc
using something like this
http://cgi.ebay.co.uk/DC-0-2V-50V-3-BLU ... dZViewItem
from ebay.
it should give me an accurate afr reading costs next to nothing and will look quite tidy sunk flush into the dashboard.

I read this on the MS forums and they say it works great!!

http://www.msefi.com/viewtopic.php?p=12 ... ht=#129985

http://www.msefi.com/viewtopic.php?t=21617

[donk_316]

All that fucking around for a Autometer gauge that costs 50 bucks and works FINE with a LC1? Sounds stupid.

Then you can say "see that voltmeter gauge? yeah that my AF but i was too cheap to spend the other 10 bucks for a quality correct gauge"

[cactus bastard]

Yeah, gauges are cheap, fucking around trying to save $10 on the gauge itself is a waste of time. And the sensors themselves are pretty cheap too. So why are the controllers always so expensive?