DAM @ 0.688...next steps?

List of my mods here:

http://legacygt.com/forums/showthread.php/smokey-08-gt-5eat-limited-241537.html

Running Stage 2 OTS 91Oct Cobb Map

Upgraded from a V2 to a V3 AP about a month ago and started monitoring daily driving. DAM has been at .688 ever since I started monitoring it. I get feedback knock as high as -8 to -10 while cruising, although I know it isn’t terribly relevant since I’m not at WOT.

First thing I did was switch from Loaf N Jug (gas station) 91 octane gas to Shell 91 octane …saw no difference in DAM (did not reset ECU upon switching gas). Now I’m slightly concerned, so I did a 3rd gear WOT pull today and logged it (see attachment). My apologies my log isn’t exactly 2,000 rpm to redline, but close

Zero feedback knock under WOT but my DAM stays at .688 all the time, and my boost is low…what should my next steps be?

datalog1.csv

Have any cruise logs (where you're seeing your FKC)? Would be worthwhile to try retarding timing or adding fuel in the areas you're seeing your FKC to see if it helps mitigate your knock there. That might help to bring your IAM up (though I'm not too familiar with how the coarse-knock learn works and I've never had luck getting my IAM to recover after a bad tank of gas).

Off the top of my head, the Cobb Stg2 91 map went to 16-17psi peak boost (IIRC, the Stg2 93 map goes to ~18psi peak). Are you in S or S# mode? Since your wastegate duty is pegged at around 47, I assume you're hitting your boost targets (after compensations). To me that looks like your log was in "I" mode instead of S or S#, but perhaps I'm missing something obvious.

Have any cruise logs (where you're seeing your FKC)? Would be worthwhile to try retarding timing or adding fuel in the areas you're seeing your FKC to see if it helps mitigate your knock there. That might help to bring your IAM up (though I'm not too familiar with how the coarse-knock learn works and I've never had luck getting my IAM to recover after a bad tank of gas).

 

Off the top of my head, the Cobb Stg2 91 map went to 16-17psi peak boost (IIRC, the Stg2 93 map goes to ~18psi peak). Are you in S or S# mode? Since your wastegate duty is pegged at around 47, I assume you're hitting your boost targets (after compensations). To me that looks like your log was in "I" mode instead of S or S#, but perhaps I'm missing something obvious.

This log was taken in "S" mode

Make sure you perform a boost leak test. Your learning is largely positive so it could be something going on. Also I would add AFR ratio #1, and AF correction #1 to the log list.

Altitude can play a role as well, they tend to not like it so much.

Mike

Make sure you perform a boost leak test. Your learning is largely positive so it could be something going on. Also I would add AFR ratio #1, and AF correction #1 to the log list.

 

Altitude can play a role as well, they tend to not like it so much.

 

Mike

Would a smoke test suffice for a boost leak test? My altitude = 4,658 ft

Would a smoke test suffice for a boost leak test? My altitude = 4,658 ft

Yes, but there is a pretty simple method here.

http://legacygt.com/forums/showthread.php/checking-general-health-your-engine-and-tune-210369.html

Bone stock intake and filter?

Yes, but there is a pretty simple method here.

 

http://legacygt.com/forums/showthread.php/checking-general-health-your-engine-and-tune-210369.html

 

 

Bone stock intake and filter?

Not to thread jack, but how long should the system hold pressure blowing through the BOV hose? I've seen a leak rate of ~1psi/sec is normal.

Yes, but there is a pretty simple method here.

 

http://legacygt.com/forums/showthread.php/checking-general-health-your-engine-and-tune-210369.html

 

 

Bone stock intake and filter?

Thanks for the link. Yes, bone stock intake and filter. Also cleaned the MAF about 1.5 months ago, spraying directly (but carefully) as advised on these forums

Not to thread jack, but how long should the system hold pressure blowing through the BOV hose? I've seen a leak rate of ~1psi/sec is normal.

I usually blow in with my mouth (1-2 psi), then cap it with my finger and count to five. Air should still rush out.

I followed the steps to check for leaks and was relieved to have air hissing back out upon removing my finger after 5 seconds. Reset the ECU and will log idle and cruise.

When you say 'Observe the “A/F correction #1” and A/F learning #1” the total of these two should be less then 7%', are you referring to the total of each or the total of both monitors added together?

I followed the steps to check for leaks and was relieved to have air hissing back out upon removing my finger after 5 seconds. Reset the ECU and will log idle and cruise.

 

When you say 'Observe the “A/F correction #1” and A/F learning #1” the total of these two should be less then 7%', are you referring to the total of each or the total of both monitors added together?

Added together. The other rule of thumb is that your learning should always be within +/- 5%. More than that is generally a good indication of a leak.

started the car up and let it warm up. DAM was even lower at .625 and stayed there for the whole drive (about 10 miles)

sum of AF correction and learning was -25/+17 and 0/6% respectively, for a total of -2

i will post a cruise and idle log at the end of the day

started the car up and let it warm up. DAM was even lower at .625 and stayed there for the whole drive (about 10 miles)

sum of AF correction and learning was -25/+17 and 0/6% respectively, for a total of -2

 

i will post a cruise and idle log at the end of the day

What are those numbers indicating? As in, what's -25, what's +17, etc.?

Keep in mind there are 4 learning values (A, B, C, D), and they'll change depending on what sort of MAF value you're at (i.e. you'll have different learning numbers at idle than at WOT). What you might want to do is pull a "learning view" to see your learning values across all ranges. You'll need a computer with Cobb's Accesstuner Race software on it, then you connect to your ECU on the computer (through the AP) and check your A/F #1 Learning table.

Here are the logs, 2 of normal highway cruising and 2 of idling in park

please keep in mind this is less than 60 miles after an ECU reset

Cruise A 1.7.16.csv

Cruise B 1.7.16.csv

Idle A 1.7.16.csv

Idle B 1.7.16.csv

FYI, saving as a .csv removes anything you did in Excel (i.e. frozen panes, formatting, etc).

Looking at those, it looks like your AF learning is positive, which means your ECU is adding fuel to meet target AFRs... it's a bit higher than I'd like, but from my understanding, your fueling in CL should be pretty much fine (and you're not running lean, at least not in the conditions in those logs).

I get very similar knock in my car in those ranges. I imagine whatever''s causing that knock (be it real or phantom knock) is what's keeping your IAM down. Keep in mind for the IAM to increase, even a single knock event will cause the ECU to restart its delay counter while it's in coarse-correction mode, which it may not even enter if the ECU isn't adding timing back in fine-correction mode. It might help to also log "Knock Sum" to see where/when the knock switch is being triggered, and how that's affecting your ECUs learning.

Also worth asking, have you checked your engine bay for anything that might be causing any sort of rattle?

A few notes on general health of the car:

- 2 oil analyses done with Blackstone and both have come back excellent

- Oil and coolant levels stay steady…if I am consuming oil, it is so little that I can’t see it on the dipstick

- OCI = 3,000 miles

- Car idles steady at 650rpm in Drive, and does not stumble (except right after I reset the ECU, it stumbles when I come to a stop… that is a normal symptom after resetting ECU and will go away after about 60 miles of driving)

I have checked my engine bay for loose bits, although I will admit...I'm the noobiest of noobs and didn’t check thoroughly. Any pics or hints on areas to check?

For one, clean your throttle body. It shouldn't take 60 miles for the stumble to calm down. When I reset, I let it idle for a few minutes and I'm good to go. Anything more and your ECU is trying to learn around a dirty throttle body.

That being said, immediately after a reset, what is the DAM value? And does it ever jump to 1? Anyway, your logs don't record engine load, but this looks like typical low load knock. Cold be caused by loose metal or timing advanced a little too far in those ranges. Even though it's an OTS map, all cars don't react the same to them. This map may not exhibit these problems on other cars.

I had the same issue. I dropped the timing a little in the problem ranges and disabled feedback knock below a certain rpm and load value. This method may be frowned upon by professional tuners, but knocking at those levels is not detrimental to the health of your engine. That was more than a year ago and I'm still running strong on 24psi with a big turbo.

The stumble was minimal and went away after driving the car twice, much less than 60 miles for sure. I will record a log with engine load (I assume that is an AP parameter?)

As soon as I did the ECU reset the DAM started off at 0.625 which is unnerving. It never jumped to 1, has been stuck @ 0.625 ever since

The stumble was minimal and went away after driving the car twice, much less than 60 miles for sure. I will record a log with engine load (I assume that is an AP parameter?)

 

As soon as I did the ECU reset the DAM started off at 0.625 which is unnerving. It never jumped to 1, has been stuck @ 0.625 ever since

The OTS maps usually have a starting DAM that's < 1. W/ my prev car (05 Saabaru 9-2X Aero on a Cobb Stage 2 OTS map that didn't exhibit knock), if I needed to reset the ECU I'd warm it up to near normal operating temp 1st, then reset the ECU and very shortly thereafter would do a moderately boosted run (approx 8-10 psi through part of 3rd or 4th, subjectively 3-5 sec duration). That always allowed DAM to increase to 1.

The stumble was minimal and went away after driving the car twice, much less than 60 miles for sure. I will record a log with engine load (I assume that is an AP parameter?)

 

As soon as I did the ECU reset the DAM started off at 0.625 which is unnerving. It never jumped to 1, has been stuck @ 0.625 ever since

The stock tune starts with a DAM on 0.5 after a reset. I don't remember the Cobb maps off the top of my head, but I imagine 0.625 sounds reasonable. I wouldn't be unnerved by that.

The AP parameter you're looking for is "Calculated Load," measured in g/s.

The stumble was minimal and went away after driving the car twice, much less than 60 miles for sure. I will record a log with engine load (I assume that is an AP parameter?)

 

As soon as I did the ECU reset the DAM started off at 0.625 which is unnerving. It never jumped to 1, has been stuck @ 0.625 ever since

Okay, I'd have to see your map. Can anybody get me the ATR file for the '08 LGT 5eat so I could look at his map? There's a table that controls when DAM is triggered. It's based off the degrees of dynamic advance. If the ECU never sees this value (usually 3 or 4 degrees of advance), then DAM will not increase. That's why after a reset, jumping into boost is the accepted method of increasing the DAM to 1 since the higher load columns have higher advance figures. I'm wondering if you have tables that are improperly set so DAM cannot increase. Lower than 1 DAM value decreases WGDC in turn limiting boost which you are experiencing, also.

That could be what is hindering DAM from rising then... ever since the ECU reset I've been driving the car carefully (since things seem off) and staying out of boost.

I don't mind doing a boost run, seeing as how I never had knock at WOT.

Would you recommend it?

That could be what is hindering DAM from rising then... ever since the ECU reset I've been driving the car carefully (since things seem off) and staying out of boost.

 

I don't mind doing a boost run, seeing as how I never had knock at WOT.

 

Would you recommend it?

If you don't see knock at WOT, I say go for it. You don't necessarily need to go WOT but WOT should do it. Warm up the car first, then shut it down, reset the ECU, then start a 3rd or 4th gear pull from around 2000 or so. If you display DAM on the AP screen you can keep an eye on it during the pull to see if/when it increases. It shouldn't take more than a few seconds under boost to bring DAM up.