02 Sensor and A/F

xtremeIX · Sep 1, 2006, 12:02 PM

I recently installed an Apexi Turbo Timer in my car and I'm having some difficulty understanding all of the vocabulary in the installation instructions in regards to the o2 sensor voltage and A/F ratio. The instructions can be viewed here providing you have Adobe Acrobat Reader:

http://www.roadraceengineering.com/i...structions.pdf

If you look in the instructions under the topic "A/F value, o2 sensor voltage setting" I'm a little lost as to how adjustments are made. There are 8 different values I can select under the o2 sensor voltage which are: 960, 940, 820, 450, 010, 006, 004, and 002. I believe the number I'm looking for to show at idle in closed loop mode is 14.7:1. On top of this, I have modifications done to my car which are listed in my signature which leads me to question if I'm still looking for 14.7:1 to be the ideal A/F ratio since my FLASH included adjustments to the A/F.

KevinD · Sep 2, 2006, 09:25 AM

because the turbo timer is using the stock o2 sensor you are not going to be getting any usefull data with it. it will oscillate back and forth between rich and lean at all conditions except WOT. at WOT it will still be for the most part useless as it will display a rather broad range of rich condition, or lean condition. however, because it is simply a O2 sensor, 14.7/14.6 is the a/f ratio you want the sensor set at. if you are using a different type of fuel then you would want to set it at something else (for instance, E-85 would be 10:1).

xtremeIX · Sep 18, 2006, 02:03 PM

Thanks, now does anybody know which wire on the ECU is for the o2 sensor (Evo IX ECU). There is an ECU pin chart floating around but it's not accurate and I would really like to get it right the first time.

kjewer1 · Oct 23, 2006, 04:44 AM

This is a bit late perhaps, but for the archives, I would prick the wire the chart says to use and watch for oscillating voltage at idle. That should be a dead giveaway. On the 05 harness the front and rear O2 signals are side by side though, so if you still use the rear O2 sensor try not to mix them up if that chart is off. If you hav a cat the oscillation will be a good bit less on the rear o2 sensor (nearly flatline in many cases), if you use a test pipe they 2 sensors should display the same behavior.

RallyRedIX · Mar 27, 2007, 11:12 PM

xtremeIX.......

is your auto timer working 'cause i can't seem to get mine working. i used the hks harness, the o2 sensor is spliced with pin 71 and it's grounded to one of the ecu grounds. my auto timer, a/f guage, and o2 guage are not working.. only the volt meter and the manual timer work correctly.