Just put in an autometer a/f gauge to fill up a third hole in my guage pod and it's driving me crazy. It just randomly sweeps back and forth most of the time. Of course if I get on the gas it shows rich but if I'm idling or just going down the road it randomly goes back and forth.

I have another a/f guage built into my apexi TT that shows the voltage that the o2 sensor puts out and sure enough, the voltage jumps all over the place. I guess the Apexi has a buffer, though, because it's digital a/f display stays pretty stable despite the unstable voltage.

Anyone else have this experience or know if there is a solution? I would just tear it out except it took me forever just to install everything.

 

Have the same problem with my Autometer A/F guage.

 

The autometer A/F gauge is design to go back and forth like that,
the gauge is only useful when your at WOT. Those gauge are only for SHOW not really useful at all.

 

What type of crap is that.
This seems to be true. Stupid gauge

 

this symptom is not unique to the autometer gauges. its just how the o2 output varys. A/F gauges based on none-wideband o2 sensors are only designed to read accuratly between rations of around 14-15:1 and when you floor the gas, the ECU goes into closed loop and bypasses the o2 readings since the readings are no longer accurate. one should only use the information of an a/f gauge only in the middle where its accurate and at the two extremes. any reading inbetween is just BS. those economical sensor are just not meant to read that kind of A/F ratios, doesn't matter what meter is connected to it.

there is also no difference at all between a single wire and a 3wire o2 sensor. all it does is heat up a minute quicker with a built in heater when the car is first started and its cold. its the same sensor inside and is not any more accurte than a single wire.

 

The gauges you are using are using your stock "narrow" band o2 sensors. The best way to tune a/f mixture is to use a wideband o2, much better than an EGT gauge too. They are expensive, but if you are going to tune your car yourself or on the street it is the way to go. Check out widebando2.com.

 

yes ditch your 1v blinky light machine. Its only using the factory front o2 sensor, which only tells the ecu if the engine is rich or lean. 1v being 15:1.

The BEST wideband o2 sensor on the market = http://www.innovatemotorsports.com/lm1.php

I ordered it a few days ago... for the price and quality you cannot go wrong. They are adding an RPM input very soon.

 

To clear up some misinformation - the gauge is ONLY useful when it cycles back and forth - that is your only indication that the ecu is trying the keep the car stoich (an air-fuel ratio of 14.7 :1). This occurs when the car cruises at a constant speed or idles). Once you go on or off the throttle, these gauges largely become pretty useless for anything more than show. the reason as stated above is that they are relying on a narrow band 02 sensor for their feedback (and whats worse, they are tapping into an existing sensor - the ones that use their own sensor are better but not by much). these gauges are VERy inaccurate at anything other that stoich, becuase narrow band 02 sensors are very inaccurate at anything other that stoich.

these gauges work by assigning a certain voltage to a given air-fuel ratio. That voltage is then assigned a bulb in the spectrum. Problem is, we don't know what bulb equals what air fuel ratio..all we know is that the gauge is alleged to indicate "rich" or lean" (as oposed to how rich or how lean). As any tuner can tell you, a car is rich at .90 volts just as it is at 1.0 volts - but there can be a HUGE difference in how the car runs, and a huge difference if you datalog it. This is where you start to to see the uselessness of the gauges.

LOTS of companies make wideband 02 sensors, some better than others. The best are still the most expensive (Motec, Horiba), though many of the lower priced units are quite good. Turbo XS has one coming out, AEM has one out (display unit coming soon), FJO is probably the most widely used (has a nice display offered as well), or if you do a Google search, you can actually buy a do it yourself kit out of Australia.

Good luck

 

I knew the gauge was useless when I put it in. It was meant as a hole filler for the triple gauge pod I got. I just didn't know it would be as spastic as it is. Atleast the Apexi a/f guage in my tt stays somewhat stable. Maybe I'll replace it with an oil pressure guage.