About to throw in the towel nailing down idle

[BBA]

I went back through the TBSS with the cam in it, mostly trying to get 4th gear to work (which I did get working, thank you) and you know...I tried all the stuff you guys wrote here and it really didn't make a difference. I kind of used a combination of the different things 5LE did and I tried the overspeed settings LAZ used, not really making anything better (actually it went back to being worse). I ended up with a good compromise that gave a little smoother idle and better recovery, but I can't get it to idle under 850-900 RPM still.

Oh well...a cam just can't be hidden but so much.

[5_Liter_Eater]

Things are still running very good @ 35* with my min RAF tuned like I said and stock proportional, integral and adaptive idle spark tables. I was going to try and shift out my adaptive spark, proportional and integral tables a bit but I just created a custom PID and histo to show me how far off from my commanded idle speed (850) I am when TPS pedal is <1% and I'm within 26 RPM's.

[BBA]

Yeah, 850 was the lowest I could get this one to idle smoothly at, and it's still not all that smooth either.

[ShoddyHog]

Well, I take a couple weeks off tuning, and damned if you guys haven't almost gotten this figured out. By the time I get my widband insalled and get my VE table away from a SWAG, all I should have to do is cut & paste y'all stuff in

Good info in this thread...thank you to all who have contributed. Now, I need the weather to cooperate and to get a bunghole welded in. I have clutch-push-idle-drop down to nothing, driveability is much improved, and had starting problems until I started doing the BBA tweak. Right now, I just need to get that VE squared away, fix airflow, and go from there.

TThe high/low octane tables are only used when you start moving passed a certain MPH and TPS value (not accessible via HPTuners, but older LS1 have it if you want to look at it).

Thank you...I've asked this same question elsewhere and came up with no good answer. I was wondering when it switched, and could not find those values for my LS2. Edit: Based on your statement, I thought I could load a LS1 tune and find the values. I must be missing them. Do you know what those values are and if they are the same for the LS2?

Gerry

[Cyclone Chris]

5L - Could you please explain what procedure you exactly used to get the RPM error so low? My idle has been acting so funky, I'm not sure where to start.

When I start up the car the car idles fine, hot or cold. However, once I start doing some spirited driving, and come to a stop light my idle goes to 900 (commanded), then it jumps upto 1100 - 1200. It's like it tells itself.... "oh shit I shouldn't be this low, and quickly corrects itself.

[5_Liter_Eater]

- Set target idle RPM to no less than 850 (for the time being)
- Increase base spark in idle range to at least 25 - 35*
- Zero the min RAF table
- Set adaptive spark tables and idle adaptive proportional and integral tables to stock
- In your driveway start the motor and in VCM controls, set spark idle control to "on". Log airflow against the min RAF table (histo 10), commanding the different RPM's in the table from 650, 800, 1000, 1200. You can only command up to 1200 RPM's in the VCM Controls. For 1600...3000 you need to hold the throttle to keep it at the desired RPMs.
- Paste these numbers directly into the min RAF table for all gears (for auto guys you may need to do this twice, once in park and once in gear w/ the e-brake on). Then subtract 10% from everything.
- Now log adaptive advance against the min RAF table (histo 11). Command the RPM's again, just like before. Copy and paste these numbers (paste special, multiply by %) into the appropriate cells. (again, auto guys will need to do this twice) Rinse, repeat until the adaptive spark numbers are +-1 degree.

[BBA]

Thanks Bill, I might have to try that part the next time I get Matt's truck.

[Cyclone Chris]

From the Histo are you subrating 10% from the Average / Min / Max values?

Do you keep RAF past 3K RPM set at zero after you're all done?

Thanks
Chris

[5_Liter_Eater]

Use the average for both histos. Subtract 10% from the average min RAF airflow values as a start then use the average adaptive idle values to alter them from there.

I do zero the min RAFR after 3000 RPM. I don't see a reason to have a minimum RAF defined after that.

[Cyclone Chris]

Thanks

Which Idle Adaptive tables are we talking about here? Is this Under Spark Control or Idle Adaptive Proportinal Tables (next to the commande idle speed)??

[5_Liter_Eater]

The Proportional and Integral adaptive idle next to the Idle RPM as well as the idle adaptive overspeed and underspeed in the spark advance page. Sorry, should have been more specific.

[Cyclone Chris]

The Proportional and Integral adaptive idle next to the Idle RPM as well as the idle adaptive overspeed and underspeed in the spark advance page. Sorry, should have been more specific.

Sorry, but I still do not follow. The lables are not the same from the scanner to the actual editor tables you specified.

The scanner has 650, 800, 1200, 1600 etc...

The editor ranges from -512 to +512 for airflow and 0 to 512 for the spark overspeed and underspeed P/N

I guess I really do not understand where and how you are paste - special Multiple by % at.

[EC_Tune]

You can only command up to 1200 RPM's in the VCM Controls. For 1600...3000 you need to hold the throttle to keep it at the desired RPMs.

Bill, If you type the desired RPM in the box and then select "On" it will go to that RPM. But the +/- values won't take you there.

[5_Liter_Eater]

Bill, If you type the desired RPM in the box and then select "On" it will go to that RPM. But the +/- values won't take you there.

Ah ha! Good tip, thanks Doug!

[5_Liter_Eater]

Sorry, but I still do not follow. The lables are not the same from the scanner to the actual editor tables you specified.

The scanner has 650, 800, 1200, 1600 etc...

The editor ranges from -512 to +512 for airflow and 0 to 512 for the spark overspeed and underspeed P/N

I guess I really do not understand where and how you are paste - special Multiple by % at.

I'm saying to leave your idle overspeed and underspeed tables stock as well as the idle proportional and integral.

As far as the pasting of the adaptive spark, histo 11 shows the amount of adaptive spark and plots it against the minimum final airflow table. You're going to use the amount of spark added or subtracted as a percentage of how far off the final airflow minimum table is so you take the numbers in histo 11 and paste special, multiply by % into the min final airflow table. Its not intuative and not scientifically correct but it works.

[Cyclone Chris]

I'm saying to leave your idle overspeed and underspeed tables stock as well as the idle proportional and integral.

As far as the pasting of the adaptive spark, histo 11 shows the amount of adaptive spark and plots it against the minimum final airflow table. You're going to use the amount of spark added or subtracted as a percentage of how far off the final airflow minimum table is so you take the numbers in histo 11 and paste special, multiply by % into the min final airflow table. Its not intuative and not scientifically correct but it works.

I see what you're saying now....

Basically

RAF Table = (Min Air Flow histo 10 - 10%) * adaptive spark histo 11

Essentially we're not messing around with any spark tables except initially when you set them for 25 - 35* under the idle spark.

[Cyclone Chris]

Also, I just did the Min Air Flow thing yesterday, without any adaptive spark changes, and everything was working decent.... I was getting a 900 rpm idle (commanded 850).

However today, after some driving around (colder day also) my idle jumped upto 1200 rpm. Once I restart the car is goes back to normal and after some spirited driving it will bounce upto 1200.... very weird.

I'll try that adaptive spark % change to the RAF and see what happens.

Thanks Bill... appreciate the help.

[5_Liter_Eater]

You're getting there. I think what you'll find is that the RAF is too high and adaptive spark is taking a lot of spark out.

[Cyclone Chris]

You're getting there. I think what you'll find is that the RAF is too high and adaptive spark is taking a lot of spark out.

If I remember correctly I saw -4* at 800 rpm and -7* at 1200 rpm.

Did you also get idle surging when you zero'd out the RAF table to log Min Airflow? My surged or idle hunted even with the Spark idle switched turned on in the VCM Controls. 1200+ idle was fine with the table zero'd out.

Speaking of zeroing out the table... for the first time I've started to notice a slight lag in acceleration once I hit 3000 rpm. It the same feel as if there is no fuel, however the STFT's and WB read ~14.7 I have a feeling there is a reason why the factory had values all the way through the RPM band.

[Cyclone Chris]

You're getting there. I think what you'll find is that the RAF is too high and adaptive spark is taking a lot of spark out.

Our Cams look very similar, I'm running my RAF at 9.0 @ 800 rpm. Is yours any lower than that?