ECU reset-> 16 IAM = "aggressive" knock correction

BIGSKYWRX · 05-08-2005, 12:30 PM

I did a log w/ a oe ecu (3rd gear pull ~1800-redline) and found the IAM to stay right at 16, knock correction started in the 5ish range-> 9ish range @ ~3000 rpms-> to a high of a 10.5 @~ 4800 rpms -this is on a ECU that had not been reset in a couple of months.

I then put in my reflashed ECU (Ecutek), I advanced the IAM to 16 in matter of seconds (Shiv's "trick") and then immediately did another 3rd gear pull- the knock correction quickly advanced to 10 by ~ 2700 rpms, then dropped and hovered between 5 and 3 throughout the rest of the pull. The IAM stayed at 16 until ~ 3100 rpms and then started dropping- reaching a low of 6 @ ~3600 rpms and gaining one back to 7 @ ~ 4200.

Could this be a function of "fine learning"? Is knock correction more aggressive immediately following a reset?

If (I will

) repeat this in a couple of weeks of driving- is it possible (likely?) to see different results ie IAM remaing the same, knock correction "less aggressive"?

<----- knows suspensions pretty well, has long way to go w/ EM

Danka

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Uncle Scotty · 05-08-2005, 11:08 PM

....try the same thing with 100 octane in the tank and see what happens

BIGSKYWRX · 05-08-2005, 11:17 PM

I hear you, would be better even w/ 93

I have read a couple of threads that hint at the knock correction being a little "agressive" w/ a clean slate- I guess I'll find out.

thesmokingman · 05-08-2005, 11:20 PM

Quote:

Originally Posted by BIGSKYWRX

I have read a couple of threads that hint at the knock correction being a little "agressive" w/ a clean slate- I guess I'll find out.

Sounds plausible, especially given the OEM safey concerns.

Uncle Scotty · 05-09-2005, 02:29 AM

Quote:

Originally Posted by BIGSKYWRX

I hear you, would be better even w/ 93

I have read a couple of threads that hint at the knock correction being a little "agressive" w/ a clean slate- I guess I'll find out.

....what I meant was that you could 'see' the difference and that would make it all the clearer to you.....

mbiker97 · 05-09-2005, 08:38 AM

When my got my ECU reflashed my tuner put my IAM at 16 as the base number. It learned very quickly, and agressively.

BIGSKYWRX · 05-09-2005, 09:28 AM

Here's a quote from Vaus in another thread "I've noticed that immediately after a reset, the ECU is "eager" to adjust the IAM based on any knock sensor feedback within the specified learning range. After driving the car for a while, however, the IAM becomes more or less static unless a lot of knock is detected. Once the IAM has settled, the fine ignition learning can adjust a good deal without effecting the IAM"

My thought is if true, then a map that has a "little time under it's belt" might easier to deal w/ ?

Scotty- I'm running crappy 91 pump gas- the best we are "blessed" w/- I would guess that w/ higher octane I would see less knock correction (w/ a corresponding less likelyhood of seeing a drop in IAM).

jblaine · 05-10-2005, 09:41 AM

With higher octane, I'd expect you to see HIGHER "knock correction" (more timing).

jblaine · 05-10-2005, 09:45 AM

Quote:

Originally Posted by Vaus

I've noticed that immediately after a reset, the ECU is "eager" to adjust the IAM based on any knock sensor feedback within the specified learning range. After driving the car for a while, however, the IAM becomes more or less static unless a lot of knock is detected. Once the IAM has settled, the fine ignition learning can adjust a good deal without effecting the IAM

I don't know what Ed was basing this on, but it's pretty empty without data. IAM becomes more or less static-SEEMING because it has settled, IMO. Go fill up on 87 octane, without an ECU reset, and you'll see how quickly IAM drops.

BIGSKYWRX · 05-10-2005, 09:56 AM

Quote:

Originally Posted by jblaine

With higher octane, I'd expect you to see HIGHER "knock correction" (more timing).

Correct- I mistated- meant a lower drop in correction.

If there is no difference in a ecu that is freshly reset and one that isn't- curious why deltadash "warns" you that you will lose all fine learning, etc.

What role does all of the fine learning play in the scheme of things?

Big Sky

jblaine · 05-10-2005, 10:05 AM

It's nothing different than (in concept) long-term fuel trim.

Who knows why DD "warns" you. Just a notice that your car might run like ass for a few days and not to panic, I'd guess.

BIGSKYWRX · 05-10-2005, 10:12 AM

The car does run better then (everything being equal- octane etc) after it has some "learning" under it's belt?

Is it possible knock correction is "learning" more eagerly w/ a reset vs a month w/o a reset?

Thanks

jblaine · 05-10-2005, 10:12 AM

If you want more details, read these http://forums.nasioc.com/forums/show...3&page=1&pp=25

That's about the best info some of us were able to gather.

BIGSKYWRX · 05-10-2005, 10:18 AM

Danka

05-08-2005, 12:30 PM	#1
BIGSKYWRX Scooby Guru Member#: 7958 Join Date: Jul 2001 Location: Plains of Eastern Montana Vehicle: 09 GH B+	ECU reset-> 16 IAM = "aggressive" knock correction I did a log w/ a oe ecu (3rd gear pull ~1800-redline) and found the IAM to stay right at 16, knock correction started in the 5ish range-> 9ish range @ ~3000 rpms-> to a high of a 10.5 @~ 4800 rpms -this is on a ECU that had not been reset in a couple of months. I then put in my reflashed ECU (Ecutek), I advanced the IAM to 16 in matter of seconds (Shiv's "trick") and then immediately did another 3rd gear pull- the knock correction quickly advanced to 10 by ~ 2700 rpms, then dropped and hovered between 5 and 3 throughout the rest of the pull. The IAM stayed at 16 until ~ 3100 rpms and then started dropping- reaching a low of 6 @ ~3600 rpms and gaining one back to 7 @ ~ 4200. Could this be a function of "fine learning"? Is knock correction more aggressive immediately following a reset? If (I will ) repeat this in a couple of weeks of driving- is it possible (likely?) to see different results ie IAM remaing the same, knock correction "less aggressive"? <----- knows suspensions pretty well, has long way to go w/ EM Danka * Registered users of the site do not see these ads.

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05-08-2005, 11:08 PM	#2
Uncle Scotty NASIOC Supporter Member#: 16200 Join Date: Mar 2002 Vehicle: OK Houston we have an Uncle	....try the same thing with 100 octane in the tank and see what happens

05-08-2005, 11:17 PM	#3
BIGSKYWRX Scooby Guru Member#: 7958 Join Date: Jul 2001 Location: Plains of Eastern Montana Vehicle: 09 GH B+	I hear you, would be better even w/ 93 I have read a couple of threads that hint at the knock correction being a little "agressive" w/ a clean slate- I guess I'll find out.

05-09-2005, 08:38 AM	#6
mbiker97 Scooby Guru Member#: 7922 Join Date: Jun 2001 Chapter/Region: MWSOC Location: Tucson Vehicle: 04 CTS-V b/b/b 99 GMC Highrider	When my got my ECU reflashed my tuner put my IAM at 16 as the base number. It learned very quickly, and agressively.

05-09-2005, 09:28 AM	#7
BIGSKYWRX Scooby Guru Member#: 7958 Join Date: Jul 2001 Location: Plains of Eastern Montana Vehicle: 09 GH B+	Here's a quote from Vaus in another thread "I've noticed that immediately after a reset, the ECU is "eager" to adjust the IAM based on any knock sensor feedback within the specified learning range. After driving the car for a while, however, the IAM becomes more or less static unless a lot of knock is detected. Once the IAM has settled, the fine ignition learning can adjust a good deal without effecting the IAM" My thought is if true, then a map that has a "little time under it's belt" might easier to deal w/ ? Scotty- I'm running crappy 91 pump gas- the best we are "blessed" w/- I would guess that w/ higher octane I would see less knock correction (w/ a corresponding less likelyhood of seeing a drop in IAM).

05-10-2005, 09:41 AM	#8
jblaine Scooby Guru Member#: 8512 Join Date: Jul 2001 Chapter/Region: South East Location: St. Pete, FL Vehicle: 2002 WRX chassis... stage-infinity.com	With higher octane, I'd expect you to see HIGHER "knock correction" (more timing).

05-10-2005, 10:05 AM	#11
jblaine Scooby Guru Member#: 8512 Join Date: Jul 2001 Chapter/Region: South East Location: St. Pete, FL Vehicle: 2002 WRX chassis... stage-infinity.com	It's nothing different than (in concept) long-term fuel trim. Who knows why DD "warns" you. Just a notice that your car might run like ass for a few days and not to panic, I'd guess.

05-10-2005, 10:12 AM	#12
BIGSKYWRX Scooby Guru Member#: 7958 Join Date: Jul 2001 Location: Plains of Eastern Montana Vehicle: 09 GH B+	The car does run better then (everything being equal- octane etc) after it has some "learning" under it's belt? Is it possible knock correction is "learning" more eagerly w/ a reset vs a month w/o a reset? Thanks

05-10-2005, 10:18 AM	#14
BIGSKYWRX Scooby Guru Member#: 7958 Join Date: Jul 2001 Location: Plains of Eastern Montana Vehicle: 09 GH B+	Danka