School me on O2 switchpoints

[ddnspider]

I have performed AutoMAF and AutoVE several times and the car seems to run pretty good. I just took a look at my LTFT's and they look pretty good except for at idle where its down in the 500-600rpm range, and at WOT. I was originally getting the lazy O2 code's with the long tube headers until I switched to the Bosch Corvette O2's, then everything was okay.I also updated my O2 switchpoints in an attempt to bring the idle LTFT's closer to zero. Can you guys take a look at my log and O2 switchpoint table and let me know what you think? PS, I did not have a wideband on the car during the log.

PS Car is a 1998 Z28 A4 with intake and exhaust.

[ddnspider]

Bump!!! Looking for input. Doing a search gives me bits and pieces and I found more info over on HP Tuners than I did here unfortunately.

[ScarabEpic22]

Set all to 450mv, if you're trying to adjust them to 0 LTFTs that is NOT the way to do it. Could always go OL for idle and not worry about it, or disable LTFTs altogether (if your tune is correct, you dont really need them).

[ddnspider]

Set all to 450mv, if you're trying to adjust them to 0 LTFTs that is NOT the way to do it. Could always go OL for idle and not worry about it, or disable LTFTs altogether (if your tune is correct, you dont really need them).

Can you give input into why other threads show people logging and trying to adjust them based on the airflow levels.

[joecar]

Can you give input into why other threads show people logging and trying to adjust them based on the airflow levels.

Can you post some links.

[ddnspider]

Can you post some links.

Just a few examples from a google search...
http://www.hptuners.com/forum/showthread.php?t=11333

http://www.hptuners.com/forum/showthread.php?t=36956

http://forum.efilive.com/archive/index.php/t-8515.html

I am trying to understand the following:

A) I've performed AutoVE and AutoMAF several times and the car runs pretty good. However, I seem to have +LTFT's ~5% at low idle (550rpms) and at WOT, everywhere else looks really nice. How would moving the O2 switch points around in the idle and high airflow ranges affect this?

B) What is the best way to go about logging this or doing a map? Are there any tutorials?

C) Alot of people seem to have issues doing this or, should I say, need to do this when adding long tubes due to O2 placement. I posted a pic when I exported my O2 voltage and airflow to an excel and manually sorted and tried to average, but it is definitely not 450mV across the board. Does it look wrong?

[Gregs]

Just a few examples from a google search...
http://www.hptuners.com/forum/showthread.php?t=11333

http://www.hptuners.com/forum/showthread.php?t=36956

http://forum.efilive.com/archive/index.php/t-8515.html

I am trying to understand the following:

A) I've performed AutoVE and AutoMAF several times and the car runs pretty good. However, I seem to have +LTFT's ~5% at low idle (550rpms) and at WOT, everywhere else looks really nice. How would moving the O2 switch points around in the idle and high airflow ranges affect this?

B) What is the best way to go about logging this or doing a map? Are there any tutorials?

C) Alot of people seem to have issues doing this or, should I say, need to do this when adding long tubes due to O2 placement. I posted a pic when I exported my O2 voltage and airflow to an excel and manually sorted and tried to average, but it is definitely not 450mV across the board. Does it look wrong?

A) I'm a little confused, you want to adjust your AFR by moving the switchpoints? I played around with switchpoints a long time ago and found that its best to have them all set to 450 mV. At WOT your o2 sensors aren't part of the equation so you probably need to adjust the top part of your MAF curve to fix that problem. For idle I would really not be concerned with having a slightly off LTFT, however having a cam changes things a little bit for me.

B) yes there are tutorials included in the efilive documentation.

C) I don't have longtubes so i haven't had to mess with adjusting the o2's for them. Honestly right now I'm running with MAF enabled and no 02's; I've had my best results doing it that way. If i had headers I would definitely forget using o2's. They add an extra layer of complexity and reduce reliability, I don't think they're necessary.

[Gregs]

I also updated my O2 switchpoints in an attempt to bring the idle LTFT's closer to zero.

Adjusting the switchpoints is the wrong procedure to fix this issue, set all switchpoints to 450 mV and tune the VE and MAF tables.

[ddnspider]

A) I'm a little confused, you want to adjust your AFR by moving the switchpoints? I played around with switchpoints a long time ago and found that its best to have them all set to 450 mV. At WOT your o2 sensors aren't part of the equation so you probably need to adjust the top part of your MAF curve to fix that problem. For idle I would really not be concerned with having a slightly off LTFT, however having a cam changes things a little bit for me.

B) yes there are tutorials included in the efilive documentation.

C) I don't have longtubes so i haven't had to mess with adjusting the o2's for them. Honestly right now I'm running with MAF enabled and no 02's; I've had my best results doing it that way. If i had headers I would definitely forget using o2's. They add an extra layer of complexity and reduce reliability, I don't think they're necessary.

For B), I know there are tutorials about setting up a MAP in general. I am looking for more information regarding how I would setup a MAP for this specific thing. Meaning, would I plot O2 mV data for WB02 A/F vs. airflow?

[joecar]

+1 for setting the switch points to 450 mV.