I know this question has probably been asked countless times before, and I've done a search under the topic, but can't find an answer. How the heck do I check my air/fuel ratio on Autotap? Also, what should it be at for optimal performance? I've got my MAFT ready to tune my car, but don't know how to check the A/F. <img border="0" title="" alt="[Confused]" src="images/icons/confused.gif" /> I just got my laptop with Autotap today, so I'm really new at this. Any help is appreciated guys. <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />

 

You can't use AutoTap to see your A/F ratio unfortunately. All autotap will show is your commanded A/F ratio. I'll tell you the way I tuned mine, and when I took it to the dyno, I was right on the money. I autotaped several WOT runs then use the widely available spreadsheet to average my B1S1 and B1S2 O2 numbers. You want to get them around .890 at WOT. If it's above .890 you want to start with your BASE setting and tune it to 5% lean. If they are below .890, tune it 5% rich. Do several more WOT runs. Make minor adjustments with the WOT setting. I tuned mine 2% lean until I started getting 1-2 degrees of knock retard, then I left it alone. Ended up at like 8% lean for my WOT setting. On the dyno, I was right on. Hope this helps. Remember only to pay attention to the O2's when your Fuel Trim Cell is 22.

<small>[ March 25, 2003, 01:04 AM: Message edited by: WS6 GreeN ]</small>

 

Thanks for the info, I'll try that today on my way to class. <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" /> Any other tips/advice on this?

 

You can't get A/F ratio for WOT from Autotap.
But using the O2's as described above can get you very close to the optimal A/F ratio.

 

That's funny, I can hit F7 on my old DOS version 2.5 and get the sine curve and A-Tap shows me my rich and lean mV amounts.

Knowing that .485mV is stoich (14.7:1), I can generally get a basic idea of where my A/F is.

In real time viewing, select all the O2's (both Banks, both sensors) and watch the mV's as they fluctuate. Much like above, knowing .485mV is stoich, I can get a determination of it's constant switching as to how lean or rich I am. Also at WOT, they should run somewhere between .890 - .910mV's.

May not be an exact number inasmuch as getting a constat XX.X:X number, but gives you a general idea.

 

Thanks again guys, I'll keep my eye on my O2's and try to get her tuned up. <img border="0" alt="[cheers]" title="" src="graemlins/gr_cheers.gif" />

 

Many people believe 12.8:1 is the optimum AFR @ WOT. This is the ratio that corespond to 890 mV on your pre-cat O2 sensors.