Welcome to the North American Subaru Impreza Owners Club Thursday March 28, 2024
Home Forums Images WikiNASIOC Products Store Modifications Upgrade Garage
NASIOC
Go Back   NASIOC > NASIOC Technical > Engine Management & Tuning > AccessPort

Welcome to NASIOC - The world's largest online community for Subaru enthusiasts!
Welcome to the NASIOC.com Subaru forum.

You are currently viewing our forum as a guest, which gives you limited access to view most discussions and access our other features. By joining our community, free of charge, you will have access to post topics, communicate privately with other members (PM), respond to polls, upload content and access many other special features. Registration is free, fast and simple, so please join our community today!

If you have any problems with the registration process or your account login, please contact us.







* As an Amazon Associate I earn from qualifying purchases. 
* Registered users of the site do not see these ads. 
Reply
 
Thread Tools Display Modes
Old 06-24-2012, 01:35 PM   #1
AuthenticAMD
Scooby Newbie
 
Member#: 212239
Join Date: May 2009
Chapter/Region: MAIC
Location: Woodbine, MD
Vehicle:
2020 STI
Pure Red

Default A/F Learning D

If you're running a stage 3 setup with greater than stock injectors / turbo, should the A/F Learning D value still be within 5%? Are the values determined by the rear O2 sensor? Just wanting to make sure a wideband isn't needed to determine the actual A/F of the tune during WOT conditions.
* Registered users of the site do not see these ads.
AuthenticAMD is offline   Reply With Quote
Sponsored Links
* Registered users of the site do not see these ads.
Old 06-24-2012, 02:10 PM   #2
wildt267
Scooby Newbie
 
Member#: 161812
Join Date: Oct 2007
Chapter/Region: NWIC
Location: Salem, Oregon
Vehicle:
06 Wrx STi
CGM

Default

Yes you need a another wideband or to at least relocate the stock one to the downpipe. The pressure the stock one in the stock location is subjected to makes it read richer that what the actual af is.
wildt267 is offline   Reply With Quote
Old 06-25-2012, 08:45 AM   #3
Cobb Tuning
NASIOC Vendor
 
Member#: 4803
Join Date: Mar 2001
Location: Austin, TX
Default

Quote:
Originally Posted by AuthenticAMD View Post
If you're running a stage 3 setup with greater than stock injectors / turbo, should the A/F Learning D value still be within 5%? Are the values determined by the rear O2 sensor? Just wanting to make sure a wideband isn't needed to determine the actual A/F of the tune during WOT conditions.
During WOT (or other higher throttle/load conditions), you are in open loop which means that the ECU does not monitor your actual AFR anyway. It has no clue if you are hitting your target or not. Only in closed loop does it look at AFR and adjust short and long-term fuel trims appropriately.

The A/F Learning 1 values (long-term trims) are determined by the front o2 sensor and they should be reasonable regardless of the mods assuming a good tune and the car in good mechanical condition. The different stored (and applied) values are simply across different airflow ranges, with the "D" range determined in closed loop (in the highest range) but also applied in closed loop and open loop (i.e. even WOT). So, if you have a problem with the car/tune, "D" range has additional significance as it will also impact high load operation, whether there is a problem there or not.

Bill
Cobb Tuning is offline   Reply With Quote
Old 06-25-2012, 10:59 AM   #4
AuthenticAMD
Scooby Newbie
 
Member#: 212239
Join Date: May 2009
Chapter/Region: MAIC
Location: Woodbine, MD
Vehicle:
2020 STI
Pure Red

Default

Bill,

Thanks for the explanation. The reason I was asking about the D range was because in my current tune, it is -15%, which explains why it may be lean during WOT and thus knock.
AuthenticAMD is offline   Reply With Quote
Old 06-25-2012, 11:05 AM   #5
Cobb Tuning
NASIOC Vendor
 
Member#: 4803
Join Date: Mar 2001
Location: Austin, TX
Default

Quote:
Originally Posted by AuthenticAMD View Post
Bill,

Thanks for the explanation. The reason I was asking about the D range was because in my current tune, it is -15%, which explains why it may be lean during WOT and thus knock.
That is not good. I would not go WOT until you figure out what the cause is.

Bill
Cobb Tuning is offline   Reply With Quote
Old 06-25-2012, 11:12 AM   #6
AuthenticAMD
Scooby Newbie
 
Member#: 212239
Join Date: May 2009
Chapter/Region: MAIC
Location: Woodbine, MD
Vehicle:
2020 STI
Pure Red

Default

I log on a daily basis and have been running a safe map that is confirmed to have no knock with any significant load, even WOT. Getting a BPV relocation / leakdown check / retune this Thursday.
AuthenticAMD is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Things I should have never learned, I learned from OT -=C=- Off-Topic 38 10-19-2008 02:30 PM
Civil Rights & Sex or "How I learned to stop worryin and learned to love the shocker" Asinine Off-Topic 21 08-03-2006 12:41 PM
Lessons learned, or how I learned to love Wheel Bearings rbahr New England Impreza Club Forum -- NESIC 30 11-09-2005 10:34 PM
Learning up better than learning down with AccessPORT? stang-spanker Engine Management & Tuning 1 09-26-2004 01:56 AM
ECU Learns?? Learns what? Undepelo Engine Management & Tuning 8 09-10-2004 11:42 PM

All times are GMT -4. The time now is 03:43 PM.


Powered by vBulletin® Version 3.7.0
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Powered by Searchlight © 2024 Axivo Inc.
Copyright ©1999 - 2019, North American Subaru Impreza Owners Club, Inc.

As an Amazon Associate I earn from qualifying purchases.

When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission
Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.