ok i realize the gauge is mostly rice, although a lot of people have them... but i was wondering... one night i saw a quirk that the gauge was much leaner than usual, when it would bounce back and forth it would go all the way to the end of the red, and barely light up a green one at all. then at full throttle again it would barely be into the green. i thought this was odd, and figured maybe it had something to do with me having to put 91 octane in my 11:1 h22. but then the next morning everything was back to normal, when it would bounce back and forth it would go a few into the red, then back over and a few into the green. and at full throttle it was back to being all the way into the green.

i have the ntpog obd2 workaround so it would have been reset that night, so that may explain why it went back to normal, but any suggestions why it was running leaner than normal?


[Modified by Flavour, 10:01 PM 8/19/2002]

 

i also have this gauge and the damn gauge is faulty. i think it never has gone all the way up into the green part...when on WOT its goes to like the middle yellow..barely green, i think its gay as hell, but i got mine for about 15 bucks from a friend that worked fine before he uninstalled it....nothings wrong with my motor, i think its just a p.o.s. gauge...

 

all i gotta say is... you get what you pay for.

 

apexi a/f gauge kicks ***!!

 

he's a good friend...he showed me it/tested before....better i pay 15 than 50...the deal was i bought a/f, volt, and oil press for 50 bucks..so ea. were like 17.50 ish...cuz he needed the money. imo go greddy or defi!!

 

What exactly does this gauge do? I have one installed in my prelude but it came with the car when I bought it. It has been explained to me technically what it does, but preformance wise, how good is it? What am I actually gaining from having controlled air/fuel ratio?

 

They're just a narrow band A/F guages that read voltage from the the ECU (read from I think just one of your O² sensors).

Its normal for the guage to go back and forth between totally rich and lean (closed loop mode where the ECU tunes it self modding its own fuel map) unless you're past something like 80% throttle where it switches to open loop mode using a pre defined fuel map.

Since the guage goes on solely what your ECU is reading voltage wise it probably isn't a good idea to tune with just a narrow band.... but it can still be a good problem detecting tool..... IE if you're normally in yellow and then you read red in WOT you know something is wrong....

 

The purpose of an air/fuel gauge is to read how much unburned fuel leaves the exhaust manifold, though it dosn't actually control anything by its self. The reason I have one on my car was so that I could have my Apexi Air Fuel Controller tuned. At the peak preformance of my car, the gauge is about 3 or 4 bars in the green. Anything above that I lost hp on the dyno. By the way, I would only trust the readings when your at full thr position.


[Modified by 3700 Vtec, 8:18 PM 8/20/2002]

 

You don't trust the readings at any throttle position. The standard O2 sensor is only accurate at 14.7:1 a/f ratio. Any richer or leaner and the signal is highly dependant on exhaust temperature. It's only meant for closed loop control which is for emmissions and low throttle cruising (when the a/f gauge is swinging back and forth, it's in closed loop mode).

All you want to know about Standard narrow band O2 sensors:
http://www.autoshop101.com/forms/h37.pdf

and Closed Loop corrections:
http://www.autoshop101.com/forms/h58.pdf

 

wow cool links....

 

so my exhaust was just hotter than normal, and that might explain the anomoly?

 

There's a few things that could explain it, including temperature and the last time I saw your car it was running really rich. Your O2 sensor maybe degraded some. You may have a problem with the electrical connections or grounding on the gauge, or you may actually have had some slight missfires causing more oxygen to go by, giving you false readings. It's difficult to diagnose,

 

missfires from 91/bad gas?