Disabling Proportional Idle

[TAQuickness]

I just received this from a guy at LS1Tech on how to disable your proportional Idle with BrandX

"In [BrandX] it is under Open/Closed Loop Fueling. There is a little button you can click to disable it. It is a different set of values for reacting to the O2 sensors for while your car is at idle"

Can any of you give me an idea of where this is in Flashscan?

[emarkay]

Would make it easier to look for things if [we all] posted what type of car, what model year, and maybe a bit more specifics - I don't recall proportional idle setting, but maybe with ETC it's in there somewhere...

[TAQuickness]

Not sure what difference it makes, but it's a '00 WS6 M6

I'm trying to dial in my LTFT SD tune. Everything is on par except for the idle range. No matter how much I take out of the VE table in the idle range, it still show's I'm running rich. I had leaned out the VE table to the point that I only had 16% as the value's in the idle range and that made the car sputter. I changed those values to 40% and the car idles better.

The only conclusion I could come to is that the PCM does something else during idle forcing it to draw more air in than it needs, or something else that skews the LTFT's.

When I presented this on LS1Tech, I was told to disable the proportional idle so I can dial in the VE table.

Unless someone know's of a better way for me to do this, this is what i'm doing:

SD tune based off LTFT's to dial in the VE table.
Rescale MAF table based off on the VE table being correct.
Idle tune based off VE and MAF tables being correct.

[jfpilla]

It could be something as simple as the RAF values, at warmed up idle, being a little off. I've been surprised at how a small change affects trims.

-Do your desiac g/s, maf g/s and dynair g/s log pretty close to each other?
-Are your trims neg. regardless of IAT while idling?
-How neg. are they at idle?

[TAQuickness]

It could be something as simple as the RAF values, at warmed up idle, being a little off. I've been surprised at how a small change affects trims.

-Do your desiac g/s, maf g/s and dynair g/s log pretty close to each other?
-Are your trims neg. regardless of IAT while idling?
-How neg. are they at idle?

These are my averages (1096 samples) from my last log.
Idle is at MAP 60 kPa & RPM @ 1200
MAF is currently disconected
Idle trims are negative regardless of IAT

average LTFT B1 % = -8.6
average LTFT B2 % = -8.2
average DESIAC = 5.59 g/s
average DYNAIR = 0.24 g/cyl
average RPM = 988.5 RPM
average iat = 14.26 *c
average map = 57.49 kPa

calculated average DYNAIR = 0.0037 g/s using this equation:

Massflow = (VE * MAP * RPM * Displacement) / IAT

Massflow: grams/sec
IAT: Degrees Kelvin
MAP: Bar
RPM: Duh!
Displacement: Cubic Meters
VE: g/cyl

Not sure if the equation is correct. I got it from NoGo at LS1Tech in the sticky "VE Table Cracked" post.


Thanks for the help guys!

[jfpilla]

It could be something as simple as the RAF values, at warmed up idle, being a little off. I've been surprised at how a small change affects trims.

-Do your desiac g/s, maf g/s and dynair g/s log pretty close to each other?
-Are your trims neg. regardless of IAT while idling?
-How neg. are they at idle?

These are my averages (1096 samples) from my last log.
Idle is at MAP 60 kPa & RPM @ 1200
MAF is currently disconected
Idle trims are negative regardless of IAT

average LTFT B1 % = -8.6
average LTFT B2 % = -8.2
average DESIAC = 5.59 g/s
average DYNAIR = 0.24 g/cyl
average RPM = 988.5 RPM
average iat = 14.26 *c
average map = 57.49 kPa

calculated average DYNAIR = 0.0037 g/s using this equation:

Massflow = (VE * MAP * RPM * Displacement) / IAT

Massflow: grams/sec
IAT: Degrees Kelvin
MAP: Bar
RPM: Duh!
Displacement: Cubic Meters
VE: g/cyl

Not sure if the equation is correct. I got it from NoGo at LS1Tech in the sticky "VE Table Cracked" post.


Thanks for the help guys!

Are you using EFI? If you are, you shouldn't have to calculate Dynair.
I have no confidence in my tuning with the MAF disconnected. I've done it, but have not had much luck.

[GMPX]

"In [BrandX] it is under Open/Closed Loop Fueling. There is a little button you can click to disable it. It is a different set of values for reacting to the O2 sensors for while your car is at idle"

Can any of you give me an idea of where this is in Flashscan?

Yes, in Development testing.......it will be out soon, we just need to finalise labels, descriptions, confirmation across all O.S's.

Cheers,
Ross

P.S - You can mention brand 'x', we won't get mad , cause there is more than one brand 'x' now.

[TAQuickness]

"In [BrandX] it is under Open/Closed Loop Fueling. There is a little button you can click to disable it. It is a different set of values for reacting to the O2 sensors for while your car is at idle"

Can any of you give me an idea of where this is in Flashscan?

Yes, in Development testing.......it will be out soon, we just need to finalise labels, descriptions, confirmation across all O.S's.

Cheers,
Ross

P.S - You can mention brand 'x', we won't get mad , cause there is more than one brand 'x' now.

Brand X is Brand X is Brand X... :lol:

You guys never cease to amaze me! Do you know what the ETA of this new feature hitting the shelves?

I went back into the PID selection and selected the appropriate DYNAIR in g/s and logged 40 miles of data this morning.

Again, these are my averages (3195 samples) @ MAP 60 kPa & RPM 1200:

Average LTFT B1 = -10.6%
Average LTFT B2 = -10.7 %
Average DESIAC = 4.94 G/S
Average DYNAIR = 15.86 G/S
Average IAT = 14.19 *C

MAF is still disconnected. Current BACKUP VE table value @ MAP 60 kPa & RPM 1200 = 44.19

[jfpilla]

Okay, this makes sense to me.
Log the same information, but, in gear for an A4 and in Neutral if M6, standing. Log from cold to totally warmed up. You're lookin to compare Desiac and Dynair and ultimately match those values. When Desiac is right it represents actual airflow at idle. If the VE's are right, matching will flatten the trims so that you can adjust them across the board.
After done and you log, include STFT's. You will get faster feedback on how you're doing.

I tuned mine with MAF zeroed and could see Dynair change with VE changes. It would seem the same thing occurs Mafless. That's why it's important that the VE's are close. If the VE's are too far off so will Dynair and then Desiac will be wrong after matching.

[TAQuickness]

Okay, this makes sense to me.
Log the same information, but, in gear for an A4 and in Neutral if M6, standing. Log from cold to totally warmed up. You're lookin to compare Desiac and Dynair and ultimately match those values. When Desiac is right it represents actual airflow at idle. If the VE's are right, matching will flatten the trims so that you can adjust them across the board.
After done and you log, include STFT's. You will get faster feedback on how you're doing.

I tuned mine with MAF zeroed and could see Dynair change with VE changes. It would seem the same thing occurs Mafless. That's why it's important that the VE's are close. If the VE's are too far off so will Dynair and then Desiac will be wrong after matching.

I'm not sure I follow you 100%. If I understood your correctly, I need to log a cold start to warm idle (in neutral, M6), including LTFT, STFT, Desiac, and Dynair. From the results of this log, I will need to match dynair to desiac?

Not trying to be hard headed here, but sometimes I need someone to spell it out to a T for me so I can grasp the concept. :oops:


I had been adjusting the VE table based on the LTFT'S to get the LTFT's at idle between -4 and 0. I had the VE value as low as 16.something% and my LTFT avg was still -8. When the Ve table value was at 16.x%, the car sputtered like a misfiring 4 banger. The surrounding VE table cells were all in the 40-60 range (from lower kPa to higher or left to right).

When I presented this on LS1Tech, Another_User suggested the proportional idle was helping to skew my LTFT's at Idle.