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DAM and FNL all ovver the place


robburns201

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i hope im in the right place now to post this...I am having some crazy numbers pop up on my AP...My Fine Knock Learn is all over the place and my DAM has went as low as .650...i am driving a 06 LGT sedan with cat back and running 91 ots AP tune....always put 93 in the tank...this has just started and has me very concerned...i attempted to log 2 3rd gear pulls...i hope i did this correctly! PLEASE PLEASE any input will be appreciated....

datalog1.csv

datalog2.csv

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Pull an LV and post. How do your long term fuel trims look like?

In any case, I am guessing you are running lean and probably have a vacuum leak somewhere. So check for that first.

LV? I'm hoping it's bad gas....I put dry gas in and octane booster in...I'm very very very green with AP/SUBARU'S/MODDING...I didn't get to many replies so I did some reading and reset my ECU...everything is back to normal "For now"....if there is anything else I can log or do to help find out why this happened please let me know......Oh and no boost leaks that I could find...thanks

 

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LV? I'm hoping it's bad gas....I put dry gas in and octane booster in...I'm very very very green with AP/SUBARU'S/MODDING...I didn't get to many replies so I did some reading and reset my ECU...everything is back to normal "For now"....if there is anything else I can log or do to help find out why this happened please let me know......Oh and no boost leaks that I could find...thanks

 

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LV stands for 'learning view'. It gives you a report of all your long term fuel trims and 'Fine Learning Knock Corrections'. It looks like this:

 

http://www.subaruoutback.org/forums/attachments/problems-maintenance/188121d1437156277-logging-ecu-data-2-5-non-turbo-what-about-iam-what-value-do-you-have-lvt.jpg

 

The four fuel trims should stay within +/-5%. They max out at 15%. If they are positive and close to 15%, you have a vacuum leak somewhere. If they are close to -15%, you probably have an obvious boost leak somewhere.

 

How did you confirm you are free from boost leak? How about vacuum leaks?

 

Also, you should not reset your ECU when you see stuff like that happening. When the ECU changes your IAM/DAM, it has noticed something wrong and is trying to protect your engine. When you reset the ECU, it no longer knows this.

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Plug ur intake, take the BPV return hose off and blow into to pressurize then put your thumb over it. Listen for leaks.

 

Stabbing the throttle (100%), dont floor it while ur having issues because you'r prob running lean and could blow it up.

2017 Subaru STI

2008 Subaru Legacy 2.5i limited

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Reflash your tune. One morning I went to Costco and had the FKL bouncing all over the place, and DAM dropped a little. I was like, WTF? I reflashed the tune before I started freaking out and weirdly, it's been fine ever since.

GTEASER's 2012 Legacy GT - Sold

GTEASER's 2009 XTeaser - Sold

GTEASER's 1992 Legacy SS - Sold

 

Stapp's Law: “The universal aptitude for ineptitude makes any human accomplishment an incredible miracle.”

 

"Simple incompetence is a far more sinister force in the world than evil intent."

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Awesome! Mine has been fine for well over 2 months now. So it's not anything mechanical or electrical. Sometimes I think that the tune somehow gets outside of the normal values or maybe the ECM didn't get a reading from all sensors prior to starting the engine and misinterpreted some input. And then goes all wonky looking for the correct values in the tables.

GTEASER's 2012 Legacy GT - Sold

GTEASER's 2009 XTeaser - Sold

GTEASER's 1992 Legacy SS - Sold

 

Stapp's Law: “The universal aptitude for ineptitude makes any human accomplishment an incredible miracle.”

 

"Simple incompetence is a far more sinister force in the world than evil intent."

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I wasn't thinking "corrupted" per se, I was thinking more along the lines of some value and correction value creating a situation where the logic of the ECM found itself outside of normal range and couldn't correct it back to a happy state.

GTEASER's 2012 Legacy GT - Sold

GTEASER's 2009 XTeaser - Sold

GTEASER's 1992 Legacy SS - Sold

 

Stapp's Law: “The universal aptitude for ineptitude makes any human accomplishment an incredible miracle.”

 

"Simple incompetence is a far more sinister force in the world than evil intent."

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Update....I did the boost leak test and what do you know I have some leaks...2 hoses that go to valve covers were cracked and shooting air out...so fixed those and then found my TMIC has pin hole also...I have a used perrin TMIC on its way to me....Did a couple logs this morning and will post them after work...Thank you guys

 

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Update....I did the boost leak test and what do you know I have some leaks...2 hoses that go to valve covers were cracked and shooting air out...so fixed those and then found my TMIC has pin hole also...I have a used perrin TMIC on its way to me....Did a couple logs this morning and will post them after work...Thank you guys

 

Sent from my 0PJA2 using Tapatalk

 

Nice!

 

FYI if you do have fkl all over the place and low dam, dont reflash. You have a problem. Reflash will just reset and you'll be susceptible to that knock again. Fix then reflash.

2017 Subaru STI

2008 Subaru Legacy 2.5i limited

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I just briefly looked through your logs and the 'AF Learning' column shows pretty high values. These refer to the four 'learned values' shown in the screenshot on post#6 of this thread. As previously said, these values should be within +/-5%. Yours go as high as 11.72% (max is 15%). You also need to log 'AF Correction' so we can see how much fuel the ECU is trying to add/remove on top of what he has learned to add/remove already.

 

Anyway, as I said before, positive values mean you are running lean---ECU measured X amount of air but actually X+Y entered the combustion chamber. Therefore, the ECU is trying to compensate by adding the appropriate amount of fuel. This could be caused by a vaccum leak (and possibly a poor tune too). And running lean potentially increases the likelihood of knock.

 

What kind of air intake do you have?

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