About to throw in the towel nailing down idle

[5_Liter_Eater]

Here's my min RAF table.

[LazMan]

5L, I saw your idle scan in that other thread ... NOT BAD AT ALL!

[Cyclone Chris]

Doesn't seen like I'm having any luck at all.

I'm on my 9th repeat with this idle adaptive paste crap....

The car seems to idle fine when I command 800, 1000, 1200.... in the VCM control section, however when I turn the RPM button off it starts idle hunting on me. I have my commanded idle table set at 850.

Any ideas?

[5_Liter_Eater]

Post a log, I'll take a look. Tune too.

[Cyclone Chris]

I'll send you the log and tune when I get to my laptop... it's pouring down rain right now

However, I may have fixed the problem. I had my idle timing set to around 32* and have noticed that the car idles very smoothly when it's around 21*

So this morning, I dropped the idle timing down to 23* and the car fired right on up without hesitation. It idle'd a whole lot better than before. Alot closer to commanded idle which I have now set to 800 rpm. I may even be able to drop it down lower.

In the past everyone has told me to increase my idle timing to fix the idle hunt problem, so I have always kept it around ~30*. I have a slightly bigger cam than yours... about .07 more lift, however the cam is 111 LSA installed at 107. Not sure if that LSA has anything to do with the amount of timing it needs.

Also my STFT are at -10 for idle... do you think I should also adjust the VE?? I run CLSD.

[EC_Tune]

With the LS2's you don't need a lot of idle timing as you have found out. Even with HUGE cams you generally don't need any more than 28-30 degrees MAX idle timing. With cams in the 220 range - stock timing to 22 degrees is pretty much ideal.

[BBA]

EC, with the LS2, there is no way to possibly get a lot of idle timing. The only thing you can get is steady timing at between 12-19º, even if you max out the high/lo tables and boost up the base idle table.

What you want to do for a large cam timing wise is set high/lo tables to 30-37º from 0-1000 RPM (all g/sec cells) and then set base idle timing higher. This reduces the cam lope from dropping timing below what the motor needs to idle.

[5_Liter_Eater]

I'm seeing around the 35 degrees that I'm commanding. My high octane and idle spark tables match. Not sure it's necessary but it's working for me so I'm leaving it for the time being.

[BBA]

So when you log actual timing, what are your idle degrees averaging? When I did this one the idle timing came around 17º on average with a little fluctuation either way.

[EC_Tune]

EC, with the LS2, there is no way to possibly get a lot of idle timing. The only thing you can get is steady timing at between 12-19º, even if you max out the high/lo tables and boost up the base idle table.

Wrong as usual. If you set the idle spark to 30 degrees you will get 30 degrees +/- whatever the overspeed/underspeed adds/subtracts.

[Bill@HPTuners]

Guys this is a TUNING forum not AAG or Lounge nor do we condone name calling AT ALL.

Time outs will be given to anyone who takes it any farther than its already gone.

We're all on the same team here guys, time to get on the same page, whether you agree to disagree or whatever, but don't resort to name calling as it makes everyone look childish which I know we are all grown men and women here.

Thanks,
Bill

[5_Liter_Eater]

So when you log actual timing, what are your idle degrees averaging? When I did this one the idle timing came around 17º on average with a little fluctuation either way.

I can't post a darn log or tune because the firewall at work but I'm seeing ~35 degrees. Adaptive idle spark will take some out and put some in constantly but on the whole it's 30-35. What IS odd though is I'd think you could just add or subtract the adaptive spark correction to/from the high octane table and you should get the actual ignition spark, but it doesn't seem to be a direct relation. Sometimes HO spark commanded will be 35, adaptive spark will be -5 and I'll see actual spark be 33. Sometimes HO spark will be 35, adaptive spark will be +5 and actual timing stays at 35.

[shizon]

I tried an interesting experiment with a car that I thought I'd share. It is idle spark related so I'll pass this on.

I had two version of the VE table. A stock version and my tuned version.

With the tuned version, it would take the car much longer to throw a p0106, but until it did, idle spark was much more erratic. If you disabled the p0106 code, that test never ran and spark would stay erratic. With the throwing of the code though, spark smoothed out much more and looked like a normal fluctuation of idle spark especially on decel.

With the tuned VE table, it wouldn't trip the code 99% of the time, which boggles me anyway as apparently I don't understand exactly what that test does. I thought it was simply a map test, but apparently it also takes into account VE limits? Anyway, again, without the code, erratic idle spark.

The fueling was 99% identical in both situations of stock ve+p0106, tuned ve + p0106, stock ve - p0106 , and tuned ve - p0106 in closed loop as you would expect after fuel trims were learned. Judged by a/f and inj duty cycle.

I don't know if this is true or why it would happen, but it seemed that disabling the p0106 code caused a difference in idle spark behavior. In either of those tunes, I could disable the p0106 code and get a surging idle on decel. As soon as I would get the car to throw the p0106 code it would stop and drive like a pussy cat.

The peanut is neither a pea nor a nut...discuss...

[5_Liter_Eater]

I haven't observed that directly but that is very interesting because on December 17th I disabled my P0106 as well. http://www.hptuners.com/forum/showthread.php?t=15720 I was getting reduced engine power when I smacked the rev limiter and would occasionally see P0106 when idling too. I looked back through this thread and I had my idle nailed down before the 17th so I'm not sure what to make of it.

Disabling P0106 could also have fixed fix the idle not being able to go below ~850. http://www.hptuners.com/forum/showthread.php?t=15436 Who knows?

[LazMan]

Disabling P0106 could also have fixed fix the idle not being able to go below ~850. http://www.hptuners.com/forum/showthread.php?t=15436 Who knows?

I dunno. I'm setting mine as in the picture (is that how you disabled the tests? and I'll try setting the idle below the A4 minimum of 550. Though...I hear Chris found something in the code is probably setting the min.

[5_Liter_Eater]

That how I disabled mine. I saw he found a table but I donno. Why would I be able to do it now?

[LazMan]

The pollution control settings sometimes have unintended consequences in the code. I knew one guy (spongalou?) that accidentally got "lean cruise" to work on his LS2 by disabling the rear O2 sensors on both banks. If you look for 'lean cruise' in the forums you'll find it. I tried to do the same thing, but it didn't work for me.

This also didn't work for me. I cannot idle below 550 no matter what I set (thats the A4 minimum).

[Joe_G]

Bill, I've got my G5x3 idling at 750 all day long. Hot or cold starts no problem, idles in traffic with AC on, doesn't die when you push the clutch in, nothing. It really drives like stock.

Here's what I did - I just copied my calibration details here. Changes here are compared to stock, and are based on logging around town.

11-3-07 changes = idle set to 750

9-20-07 VE Changes
VE table 400 - 800 row x .65
VE 1200 row x .65
1600-4000 x .75

Idle startup airflow vs ert vs ect - added 35% to table 177-305

Final idle airflow min -2 250-1000 from charlie

MAF 2800-3400 x 1.05 then x 1.01

Launch Spark = back to stock settings much better

P0300 - adjusted Engine Diag. Misfire. Idle & Normal- adjusted to ho52806 levels from stock. Turned code back on.

8-19-07 copied stock .24 table and increased 1200 to 33 as fuel mileage was down with 8-4-07 setting

9-21-07 CHANGES FOR MORE THROTTLE RESPONSE, HELPED SOME
Engine>Airflow>General Airflow>Cylinder Charge Temperature>Filter
0.208 0.216 0.224 0.237 0.254 0.27 0.286 0.303 0.319

transient fuel maximum mass SET to 900 from 2048

reduce enable delay SET to 30 from 56

Delta TPS SET to 2% from 1%

[FirstGen]

I would be interested to see your files 5 Liter, will you have a chance to post sometime or is work your only internet access?

Thanks for all of the information guys.

[LSXGOAT]

- 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.

I was having issues with my idle hunting and just couldnt get the RAF right, after i did this procedure my idle is perfect. It even idles soo well that i can just let out on the clutch without any throttle and it will get me around a parking lot without even stalling, hell i even let the lady drive it for the first time and didnt even stall it once. Thanks!!!!