Welcome to the North American Subaru Impreza Owners Club Friday March 29, 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 01-20-2013, 06:16 PM   #1
veel86
Scooby Specialist
 
Member#: 308550
Join Date: Jan 2012
Chapter/Region: MWSOC
Location: South West Michigan
Vehicle:
2006 Wrx STi
Aspen White

Default A/F learning and knock

If my A/F Learning varies more that 5.5% does this indicate that I have a fueling issue? I am experiencing a lot of FBKC.
veel86 is offline   Reply With Quote
Old 01-21-2013, 09:22 AM   #2
Cobb Tuning
NASIOC Vendor
 
Member#: 4803
Join Date: Mar 2001
Location: Austin, TX
Default

Quote:
Originally Posted by veel86 View Post
If my A/F Learning varies more that 5.5% does this indicate that I have a fueling issue? I am experiencing a lot of FBKC.
I would keep all your questions in your original thread so that all your info/logs are in one place. From what I recall with the logs you posted, there were not any extreme A/F Learning 1 values. Extreme would be something well outside of +/- 5%, say outside of +/- 8% or so.

Bill
Cobb Tuning is offline   Reply With Quote
Old 01-21-2013, 09:43 AM   #3
veel86
Scooby Specialist
 
Member#: 308550
Join Date: Jan 2012
Chapter/Region: MWSOC
Location: South West Michigan
Vehicle:
2006 Wrx STi
Aspen White

Default

Okay that's my mistake thank you mine are about 6% difference.
veel86 is offline   Reply With Quote
Old 01-21-2013, 10:37 AM   #4
Cobb Tuning
NASIOC Vendor
 
Member#: 4803
Join Date: Mar 2001
Location: Austin, TX
Default

Quote:
Originally Posted by veel86 View Post
Okay that's my mistake thank you mine are about 6% difference.
Just to be clear, you are not looking at the difference between the values, you are looking at each value individually to see if it is well beyond +/- 5%.

Bill
Cobb Tuning is offline   Reply With Quote
Old 01-21-2013, 10:58 AM   #5
veel86
Scooby Specialist
 
Member#: 308550
Join Date: Jan 2012
Chapter/Region: MWSOC
Location: South West Michigan
Vehicle:
2006 Wrx STi
Aspen White

Default

Ah... Okay my learning value C was at +6 when I looked at it yesterday
veel86 is offline   Reply With Quote
Old 01-21-2013, 11:14 AM   #6
Cobb Tuning
NASIOC Vendor
 
Member#: 4803
Join Date: Mar 2001
Location: Austin, TX
Default

Quote:
Originally Posted by veel86 View Post
Ah... Okay my learning value C was at +6 when I looked at it yesterday
That is a little borderline - I would just keep you eye on it (you can periodically check them via live data) and see if it gets worse or if another value in the other ranges starts getting extreme.

Bill
Cobb Tuning is offline   Reply With Quote
Old 01-21-2013, 12:06 PM   #7
veel86
Scooby Specialist
 
Member#: 308550
Join Date: Jan 2012
Chapter/Region: MWSOC
Location: South West Michigan
Vehicle:
2006 Wrx STi
Aspen White

Default

Okay I will what does it mean when the values are treating then 5%?
veel86 is offline   Reply With Quote
Old 01-22-2013, 08:53 AM   #8
Cobb Tuning
NASIOC Vendor
 
Member#: 4803
Join Date: Mar 2001
Location: Austin, TX
Default

Quote:
Originally Posted by veel86 View Post
Okay I will what does it mean when the values are treating then 5%?
A/F Learning 1 is based on patterns of corrections from the front o2 sensor. If the ECU sees a pattern where it has to consistently add fuel due to a consistent lean condition (as read by front o2 sensor), then it will increase A/F Learning 1 in the current range to attempt to mitigate that problem. Same if it sees a consistently rich condition, except it will decrease A/F Learning 1 in the current range. Small corrections are normal. It is also normal to see A/F Learning 1 move around and even sometimes go from positive to negative. So, there's a general rule of thumb that anything within around +/- 5% is normal. If you are well outside that (say +/- 8% or worse), then you likely have an actual mechanical issue that is contributing to your fueling issue.

Bill
Cobb Tuning is offline   Reply With Quote
Old 01-22-2013, 02:04 PM   #9
veel86
Scooby Specialist
 
Member#: 308550
Join Date: Jan 2012
Chapter/Region: MWSOC
Location: South West Michigan
Vehicle:
2006 Wrx STi
Aspen White

Default

Ahh okay I understand. Also this past two weeks I have gotten gas twice including today, but my gas tank will only fill up 3/4 of the way. There is some problem there I have to figure out but could whatever is causing that affect my A/F Learning values?
veel86 is offline   Reply With Quote
Old 01-23-2013, 08:27 AM   #10
Cobb Tuning
NASIOC Vendor
 
Member#: 4803
Join Date: Mar 2001
Location: Austin, TX
Default

Quote:
Originally Posted by veel86 View Post
Ahh okay I understand. Also this past two weeks I have gotten gas twice including today, but my gas tank will only fill up 3/4 of the way. There is some problem there I have to figure out but could whatever is causing that affect my A/F Learning values?
No, that shouldn't impact A/F Learning. You've seen +6% as your most extreme value? That is borderline - might mean nothing.

Bill
Cobb Tuning is offline   Reply With Quote
Old 01-23-2013, 10:25 AM   #11
veel86
Scooby Specialist
 
Member#: 308550
Join Date: Jan 2012
Chapter/Region: MWSOC
Location: South West Michigan
Vehicle:
2006 Wrx STi
Aspen White

Default

Yes that I've seen right now A/F Learning C has been sitting at 5
veel86 is offline   Reply With Quote
Old 01-23-2013, 10:29 AM   #12
Cobb Tuning
NASIOC Vendor
 
Member#: 4803
Join Date: Mar 2001
Location: Austin, TX
Default

Quote:
Originally Posted by veel86 View Post
Yes that I've seen right now A/F Learning C has been sitting at 5
I wouldn't worry about that. Just keep an eye on all the values over a bit more time.

Bill
Cobb Tuning is offline   Reply With Quote
Old 01-23-2013, 06:08 PM   #13
Slimsti
Scooby Specialist
 
Member#: 155696
Join Date: Aug 2007
Chapter/Region: Tri-State
Location: New Jersey
Vehicle:
2007 BLK STI Dom3XTR
415/405 Precision Tuning

Default

I was +17 in bank a and +22 in b when my front o2 was dying. Now.that's extreme. Lol
Slimsti is offline   Reply With Quote
Old 01-23-2013, 07:55 PM   #14
veel86
Scooby Specialist
 
Member#: 308550
Join Date: Jan 2012
Chapter/Region: MWSOC
Location: South West Michigan
Vehicle:
2006 Wrx STi
Aspen White

Default

Damn that makes mine look fine lol. Now my A/F Learning 1 consistently moving and stays at 5.5 and my A/F Learning C is at 5.1 and I am consistently get -2 FBKC under normal driving. What mechanical problem can cause this or possibly cause this?
veel86 is offline   Reply With Quote
Old 01-24-2013, 09:40 AM   #15
Cobb Tuning
NASIOC Vendor
 
Member#: 4803
Join Date: Mar 2001
Location: Austin, TX
Default

Quote:
Originally Posted by veel86 View Post
Damn that makes mine look fine lol. Now my A/F Learning 1 consistently moving and stays at 5.5 and my A/F Learning C is at 5.1 and I am consistently get -2 FBKC under normal driving. What mechanical problem can cause this or possibly cause this?
For your car, -2 feedback knock correction is a single count - if this is occurring at low load (normal cruise-type driving) or with larger throttle changes, then it is generally just noise. We discussed in your other thread of random -6 feedback correction and the loose lower turbo heatshield - did you get that removed?

Bill
Cobb Tuning is offline   Reply With Quote
Old 01-24-2013, 12:52 PM   #16
veel86
Scooby Specialist
 
Member#: 308550
Join Date: Jan 2012
Chapter/Region: MWSOC
Location: South West Michigan
Vehicle:
2006 Wrx STi
Aspen White

Default

Okay and yes i removed the loose turbo heat shield. While highway driving i will still get the -12 FBKC. I can't find anything rattling around or loose in the engine bay area. And because my A/F Learning 1 and C are increasing about 5.0 this indicating a fueling issue like you said before. My understanding is that the higher the value the front o2 sensor reads the more fuel is being added. I do not know my true A/F Ratio because i need to rewire the calibration wires in my innovate wide band. Do you know the possible mechanical problems that will cause these values to increase?

Thank you
veel86 is offline   Reply With Quote
Old 01-24-2013, 07:18 PM   #17
veel86
Scooby Specialist
 
Member#: 308550
Join Date: Jan 2012
Chapter/Region: MWSOC
Location: South West Michigan
Vehicle:
2006 Wrx STi
Aspen White

Default

update:
A/F Learning C increased to 5.5 and doesn't move from there.
A/F Learning 1 stays at 5.5 under throttle.
veel86 is offline   Reply With Quote
Old 01-25-2013, 08:31 AM   #18
Cobb Tuning
NASIOC Vendor
 
Member#: 4803
Join Date: Mar 2001
Location: Austin, TX
Default

Quote:
Originally Posted by veel86 View Post
update:
A/F Learning C increased to 5.5 and doesn't move from there.
A/F Learning 1 stays at 5.5 under throttle.
Keep in mind that the +/- 5% is a general rule of thumb. Doesn't mean that a 5.1 you have a definite fueling problem. Generally, I would say that +/- 6-7% is borderline reading - keep your eye on it and see if it gets worse. +/- 8-9% - there's definitely some kind of issue. +/- 10% or worse - definitely a major problem.

-12 feedback knock correction is definitely unusual. Do you have any logs of this occurring?

Bill
Cobb Tuning is offline   Reply With Quote
Old 01-24-2013, 07:28 PM   #19
nmlittlebigman
Scooby Specialist
 
Member#: 321409
Join Date: May 2012
Chapter/Region: SWIC
Location: Arrey, NM
Vehicle:
2003 Big Effing Van
7.3L powerstroke diesel

Default

Well I looked at your other thread full of broken hoses, missing nuts/bolts, loose flashlights etc. I seriously doubt that its fueling IMHO (Anythings possible though). If someone failed to properly bolt up your downpipe as referenced in the other thread and left a flashlight under your intake they could have just as easily left a can of red bull (or the missing nuts and bolts) laying on top of your motor. If I were you I'd do a serious cleaning of the engine bay and use a mirror and your new found flashlight and crawl around looking for missing bolts, brakets, broken mounts etc., While you are at it replace all of your vacuum hoses because its sounds like you've got some dry rot going on. After that I'd make sure your knock sensor is properly torqued. Then I'd build one of these:
http://forums.nasioc.com/forums/show....php?t=2205161

and leak test it myself even though the dealership "told" you that you had no leaks.
AND THEN I'd go make some pulls. But hey thats me

Good luck
nmlittlebigman is offline   Reply With Quote
Old 01-24-2013, 07:43 PM   #20
veel86
Scooby Specialist
 
Member#: 308550
Join Date: Jan 2012
Chapter/Region: MWSOC
Location: South West Michigan
Vehicle:
2006 Wrx STi
Aspen White

Default

I relooked over my car and the silicone couplar from the throttle body to the intercooler is torn... i haven't touched my car sense the Subaru dealership did work on it... Never going back there again. Could this be the cause for my A/F Learning to be high? My theory is that more air is being sucked through the torn couplar causeing my ecu to be adding more fuel.
veel86 is offline   Reply With Quote
Old 01-24-2013, 09:05 PM   #21
nmlittlebigman
Scooby Specialist
 
Member#: 321409
Join Date: May 2012
Chapter/Region: SWIC
Location: Arrey, NM
Vehicle:
2003 Big Effing Van
7.3L powerstroke diesel

Default

Yep. It can cause positive AF learning values for the reason you said (your MAF doesnt see it but your front O2 sensor does (not seeing target AFR's) thus adding fuel to correct it). Like I said before, just to make double sure of catching leaks I would build a leak tester. You only need 5 to 8 psi of pressure in the intake tract and a spray bottle with soapy water. Your car will be squeaky clean and buttoned down after you eliminate the leaks.

Last edited by nmlittlebigman; 01-24-2013 at 09:42 PM. Reason: clarify
nmlittlebigman is offline   Reply With Quote
Old 01-24-2013, 09:11 PM   #22
veel86
Scooby Specialist
 
Member#: 308550
Join Date: Jan 2012
Chapter/Region: MWSOC
Location: South West Michigan
Vehicle:
2006 Wrx STi
Aspen White

Default

Okay good will order the part tomorrow. Thank you for your advice it is much appreciated and I will do my own leak test like you said.
veel86 is offline   Reply With Quote
Old 01-24-2013, 09:40 PM   #23
nmlittlebigman
Scooby Specialist
 
Member#: 321409
Join Date: May 2012
Chapter/Region: SWIC
Location: Arrey, NM
Vehicle:
2003 Big Effing Van
7.3L powerstroke diesel

Default

No problem. I had some pesky leaks that kept creeping up and I must have leak tested a dozen times over a couple months until I finally eliminated all of them. I am so retentive about leaks that I put cable ties on every connection that didn't have a hose clamp. Like you I was logging just about every other day and was working with a tuner as well.
nmlittlebigman is offline   Reply With Quote
Old 01-24-2013, 10:45 PM   #24
veel86
Scooby Specialist
 
Member#: 308550
Join Date: Jan 2012
Chapter/Region: MWSOC
Location: South West Michigan
Vehicle:
2006 Wrx STi
Aspen White

Default

Dang I I've been doing the same thing. I have zip ties on my hoses that don't have clamps. I have a lot of zip ties haha. Those leaks are tricky.
veel86 is offline   Reply With Quote
Old 01-25-2013, 12:25 PM   #25
veel86
Scooby Specialist
 
Member#: 308550
Join Date: Jan 2012
Chapter/Region: MWSOC
Location: South West Michigan
Vehicle:
2006 Wrx STi
Aspen White

Default

My A/F Learning has been getting worse over time and it had been at 6 before. I have posted logs of this occurring in my other thread.
veel86 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

All times are GMT -4. The time now is 10:04 AM.


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.