E38 Idle hunting/adding air Please help!

[agentruley]

Yes, I have used the search function.
Yes I am read the guides and watched the videos and thought I had a good understanding of what is going on with the idle routines for these trucks.
I just got done doing a 2013 truck with a cam and after fiddling with stuff it idled nicely no problem. It had a bigger cam than this one.

Engine
6.0
factory rectangle port heads/intake manifold.
longtubes
218/228 112+3 .525 .525
6l90e
in a factory suburban.

Issues:
The idle routine is adding air from a table and I don't know what it is. It ALWAYS idles high, by about 100 rpm. Also, it starts to oscillate and buck wildly sitting still. As I come to a stop, the tps percentage is appropriate for the engine load to keep it alive as I coast down. Right as I come to a stop everything is great before the VSS reads zero, then it tries to push the truck by adding a few percent of TPS and the rpms kick back up.
Another problem is the wavy idle. This is the same program i drove around with earlier today in heatsoaked traffic with the a/c on and it never bucked or hunted. Restarted multiple times. Tried warm/hot startup. Thought it was fixed, then on my way home it does it. Up and down, only with your foot on the brake, it almost dies or pushes you into traffic. The over/under rpm behavoir matches the front 02s perfectly, rich = high rpm, lean = low rpm. help!!!! in my old ways, I would command my own afr at idle or open loop just the idle but it seems its impossible with the e38!

Things Ive tried to do to fix wavy idle:
turn off integral air
turn down/dampen spark control
adjust VVE fueling for the appropriate area.
made sure MAF readings werent too off
turned dynamic air to 300rpm.
Make sure timing tables were kinda close for idle.
add lots of minimum air, it just hangs the idle for a moment and then drops then proceeds to hunt.
took away air. it just keeps stumbling and hunting then dies.
changed desired RPM range from 600-700-75-800 and it just seems the computer will not hold the TB still below 800 rpms, which is odd since I got the previous truck with a seemingly similar operating system to hold it still no problem.

An important fact:
The ECT multiplier table is very small in this tune, and I have compared it with other factory 09 year models and they too use a .25 multiplier. while the previous truck I did had (what i thought to be) correct values of 1 after the engine was up to operating temperature.

I have included a log and the tune that seemingly lets it idle just fine, then randomly will start oscillating hard either 5 minutes after driving or 3 hours. Cant figure out what causes it.
Im down to start over again on one of these idle tuning guides, but every one i follow at the steps where it says "after you have your values and your idle is stable, blah blah blah" well my idle never is stable because the computer keeps trying to move the TB even after I zero out all adaptive air tables. there is something I am missing....

The log file:
towards the end you can see ass the VSS drops to zero the computer then starts adding tps percentage

b15MAFmode.hptburbanforforum.hpl

[kevin87turbot]

Yes, I have used the search function.
Yes I am read the guides and watched the videos and thought I had a good understanding of what is going on with the idle routines for these trucks.
I just got done doing a 2013 truck with a cam and after fiddling with stuff it idled nicely no problem. It had a bigger cam than this one.

Engine
6.0
factory rectangle port heads/intake manifold.
longtubes
218/228 112+3 .525 .525
6l90e
in a factory suburban.

Issues:
The idle routine is adding air from a table and I don't know what it is. It ALWAYS idles high, by about 100 rpm. Also, it starts to oscillate and buck wildly sitting still. As I come to a stop, the tps percentage is appropriate for the engine load to keep it alive as I coast down. Right as I come to a stop everything is great before the VSS reads zero, then it tries to push the truck by adding a few percent of TPS and the rpms kick back up.
Another problem is the wavy idle. This is the same program i drove around with earlier today in heatsoaked traffic with the a/c on and it never bucked or hunted. Restarted multiple times. Tried warm/hot startup. Thought it was fixed, then on my way home it does it. Up and down, only with your foot on the brake, it almost dies or pushes you into traffic. The over/under rpm behavoir matches the front 02s perfectly, rich = high rpm, lean = low rpm. help!!!! in my old ways, I would command my own afr at idle or open loop just the idle but it seems its impossible with the e38!

Things Ive tried to do to fix wavy idle:
turn off integral air
turn down/dampen spark control
adjust VVE fueling for the appropriate area.
made sure MAF readings werent too off
turned dynamic air to 300rpm.
Make sure timing tables were kinda close for idle.
add lots of minimum air, it just hangs the idle for a moment and then drops then proceeds to hunt.
took away air. it just keeps stumbling and hunting then dies.
changed desired RPM range from 600-700-75-800 and it just seems the computer will not hold the TB still below 800 rpms, which is odd since I got the previous truck with a seemingly similar operating system to hold it still no problem.

An important fact:
The ECT multiplier table is very small in this tune, and I have compared it with other factory 09 year models and they too use a .25 multiplier. while the previous truck I did had (what i thought to be) correct values of 1 after the engine was up to operating temperature.

I have included a log and the tune that seemingly lets it idle just fine, then randomly will start oscillating hard either 5 minutes after driving or 3 hours. Cant figure out what causes it.
Im down to start over again on one of these idle tuning guides, but every one i follow at the steps where it says "after you have your values and your idle is stable, blah blah blah" well my idle never is stable because the computer keeps trying to move the TB even after I zero out all adaptive air tables. there is something I am missing....

The log file:
towards the end you can see ass the VSS drops to zero the computer then starts adding tps percentage

b15MAFmode.hptburbanforforum.hpl

Here are a few pointers that will help out.

1. Go ahead and dial in your VVE tables. I always get them adjusted from idle to 3000 at least. It becomes less critical as rpm increases, but at idle, it's important.
2. You have way too much timing in the idle areas of your timing High Octane and Low Octane tables. Make the idle timing match what's in your Idle Spark table...around 20 degrees will work nicely with this cam.
3. Your Min Airflow Table looks way too high for this mild cam. Typically around 10 gms/sec will be a nice starting point for this combo.
4. Sometimes, I have found it advantageous to make the Overspeed and Underspeed timing tables a little more aggressive than stock, so that the timing control is more aggressive.

Just a couple of other things to note...
Your timing curve is WAAAAAYYYYY too aggressive. At 4000 rpm, I would typically be around 22 degrees max with this combo at WOT. That's with 93 octane fuel. You might run 24 degrees at 5200+rpm. Your current tune is commanding 32 degrees at 4000 rpm at WOT. That's just too much.

I would recommend disabling the 4 second PE delay for better performance.

Also adjust the 33020 ETC table to 100% for better response.

[agentruley]

thank you for your timely response, I however have a question:
I have already gotten VVE doing good with open loop and an external wideband, I will gloss over timing; I have tried lower timing values and it will not run. tends to bog down/die.
Though you say my min air flow is too much, is there a trick I am missing?
If i take any air from these values not only is the truck hard to start, but also will not idle. just dies when coming to a stop/putting into gear/revving down.
PE: in the file that I uploaded, PE is set to kick in instantly. there is no delay and the threshold is 300rpm. The wide-band confirms this behavior.

I appreciate the help, But I feel like I am missing something as these are all things I have done/normally do and get great results. but no matter what I do, this thing just keeps opening and closing the TB at idle. I will go and take air and timing away, and relog to show behavior.

But again, I thank you very much for your help. Tomorrow morning new information will be posted

[kevin87turbot]

thank you for your timely response, I however have a question:
I have already gotten VVE doing good with open loop and an external wideband, I will gloss over timing; I have tried lower timing values and it will not run. tends to bog down/die.
Though you say my min air flow is too much, is there a trick I am missing?
If i take any air from these values not only is the truck hard to start, but also will not idle. just dies when coming to a stop/putting into gear/revving down.
PE: in the file that I uploaded, PE is set to kick in instantly. there is no delay and the threshold is 300rpm. The wide-band confirms this behavior.

I appreciate the help, But I feel like I am missing something as these are all things I have done/normally do and get great results. but no matter what I do, this thing just keeps opening and closing the TB at idle. I will go and take air and timing away, and relog to show behavior.

But again, I thank you very much for your help. Tomorrow morning new information will be posted

Just so you didn't overlook my statement...make sure you match your Idle Spark table to your HO and LO timing table at idle speed.

The tune that you posted still has the stock VVE tables. I'll be glad to look at your revised tables if you'd like.

[FASSTRUK]

your map sensor settings seem incorrect, if you know the factory figures put them back. Also the prediction coefficients are zeroed. return to stock values. Lastly the minimum VSS set point should be matching your idle rpm, especially at the zero column

[07GTS]

Just so you didn't overlook my statement...make sure you match your Idle Spark table to your HO and LO timing table at idle speed.

on some e38 that can disable idle spark correction, the difference between the idle spark and main spark table can be a limit to the idle adaptive correction, keep eye out if spark isnt adding/substracting compared to whats commanded then thats the issue

[agentruley]

What settings are you referring to?
These are the factory values, I have checked over factory programs and the map sensor offset and linear slope are set the same to other factory tunes....

[agentruley]

Update: I tried those changes and it was even worse
So I decided to start over with a stock tune, and redo the VVE.
Now I have idle fueling tip top!
And with the truck in SD mode, it idles great in park. except when you turn the A/c on it dies.
It also idles low in gear now, very low. I have tried bumping up RPMS and min airflow but the TPS stays glued at 22.7%.
I just tried Minairflow table that is maxed out at 64g/s, no change in behavoir.
Can someone help me? I just dont understand whats going on, before it wouldnt take away air, now it wont add any. This is a factory 2009 6.0 suburban tune with all factory settings except dynamic airflow disabled, MAF dtcs set to mil light, MAF fail at 1hz,idle RPM, min airflow, LTFT turned off and VVE edited. Why all of a sudden it just will not add any air? Before it wouldn't STOP adding air. i am getting more and more lost. I just did a 2013 truck with great results, I thought I knew how somewhat this ecu works but apparently not.
Please note that the ONLY TABLE that controls the TB opening for more air is the ECT multiplier, MIN airflow does nothing...
Can someone help me please?
I'm okay with having to relearn, restart, admit im wrong whatever it takes.
try3yhelp.hpl2009StockBaseTune60SDMODE5.hpt

[agentruley]

Another update!
I figured out why the e38 ecu was not following minimum air tables or changing the tps or adding or removing air with idle rpm.
The fix for the computer not controlling the TPS or Throttle body is called Idle effective Area Fail max. It is under the airflow subtab of idle.
The default setting for this 2009 suburban was only 60. I changed it to 300 and boom, everything idles like it pretty much should in SD mode.
The wavy idle has for the main part stopped. A/C doesn't cut it off in park or in gear sitting still. Now coming to a stop and Revving down in park is a different story (wants to die, bucks for a hunt or too then is fine), but I think I know how to tackle those problems. But first I am going to take care of the entire VVE table to make sure fueling is okay. Hopefully after fueling, I can put the MAF back, Fix the horrible 2-1 and coming to a stop with or without the a/c on. I will keep updating this thread with information as I go. And I also post these kinds of 'moments' so hopefully the next person with the same problem will find my post, and I can save them the hassle =) If any of this does not make sense, or I should rather do -blank- before -blank- PLEASE tell me, I am trying to be the best tuner I can and any information is useful as long as its valid.

I will complete the VVE with STFTs and a wideband over the next day or so. Then I will report back after I try and fine tune the little stuff, like 2-1 and post updated files and logs. Thank you very much for whomever has helped so far, hopefully this thing shouldn't be much more trouble.

[[email protected]]

I just tuned my 2013 suburban with a ls2 6.2 transplant. Ran great. My tune ran in 6.0s with a little tweaking. Are you still stuck???

[[email protected]]

Ls3... sorry

[agentruley]

Small update:
So I put it into open loop with Speed Density and tried to get fueling relitivly close in the idle areas. Got the idle in park a lot smoother, albeit with a little bit of oscillation still in the idle (computer or engine hunting) but I noticed it wasnt spark or air related (must be the 02s switching with closed loop turned back with STFTs only to watch the idle in open loop in park). Well I decided to give the MAF another go, as SD only tuning this thing would be a waste in my opinion because it doesn't have that much cam. got some better results, however I am still needing some advice.
Heres the revisions:
I started with a stock tune again,
Followed "e38 idle tuning guide" on these forums
Turned off proportional airflow (via 4096rpm)
Changed desired idle RPM's in all tables to be 800rpm out of gear and 800rpm in gear
Put into Speed Density Mode (failed MAF)
turned off closed loop
Found (within +-5 percent) appropriate VVE values for around idle area.
turned CLosed loop and STFTs only back on.
Tested idle again, almost there still hunts somewhat maybe about a 75 rpm swing, and once again it correlates with 02s not spark or air.
I then gave the MAF a try, setting dynamic airflow enable to 300rpms, to make sure if my VVE table still wasnt right it wouldnt throw it off too bad.
With the MAF enables and these changes 90% of my idle occilastion and hunting went away in park!
Hell yeah
Now for basically everything else.

Things I now need help with:
1.When coming to a stop it doesnt really idle higher than expected but man does she wanna push you across the intersection. Maybe this is the downfall of an aftermarket cam and a stock 6l90e converter? I am thinking that maybe it needs less min airflow for in gear. However, I am afraid that If take anymore air out of it, it will stall then surge hard in the higher rpms when coming to a stop. I am going to test this now.
2.When going from park to reverse, it almost dies then just about breaks your neck (think air and spark wise controlled by the computer) and is almost hard to stop even with foot on the brakes. I dont know how to approach this.
3. When revving it up in park or neutral, when it comes back down it goes below the desired idle rpm (but holds the same TB percentage and the same spark value) then when it comes back up, the rpms stay a little high than usual and slowly the computer takes away air to settle back down to 800. (Log files I will post soon might help explain this behavoir). I tried adding min airflow once again to park and neutral but all that does is raise the value of with the TB jumps to when it tries to recover. Say I goose it, then let off, while the engine is revving down the TB percentage will go to a value say 20.8 percent. Then it goes below the desired RPM range and the computer adds air, now we are at 25.5 percent. then it is over shooting the desired RPM and slowly takes away air to reach value 22.7 or 23.3. if I add air to the park minimum airflow table, the 20.8 throttle percent during revdown DOES NOT CHANGE, how do I change this? I want the engine to have a tiny cushion of air. The torque throttle follow does NOTHING or atleast I am not using it right following online instructions.

Can yall help point me in the right direction? eventually Ill know every gosh darn routine and table these dam e38 ecu's use.

[agentruley]

Here is the tune I currently have if someone see's something obvious....

[Badassbird]

Most all of a stable idle is in correct fueling. This also means that you must anticipate the scaling of the axes and how each cell reacts to its neighboring cell. I haven't looked at a log but have seen this situation many times before in SD. Lets say with that cam that you are idling in that swing from 49 to 65 Kpa and 725 to 900 rpm. Try this and see what happens. It looks as if you have somewhere in the 1200 to 1400 GMVE numbers in that range. Grab all cells from 35 to 75 KPA and 600 to 1000 rpm and make it 1200 or 1250. My guess is that your oscillation goes away. Now keep in mind this isn't correct yet and you must tune it from there but this will show you that the difference between a cell and its neighbors are too great. You don't want to be more than a couple of percent of another at most. Also as you can see, the graph in that area is not in any way smooth. It must be as smooth as possible. Also check commanded timing in that same range and block that out also if needed to troubleshoot.

[smokeshow]

Here is the tune I currently have if someone see's something obvious....

Haven't looked at the file but from your previous post it sounds like your minimum idle rpm reference is set too high.

[Getch]

set max idle to 1200 not 800 this should help some. your virtual torque tables are set to low add at least 100ftlb.

[smokeshow]

Haven't looked at the file but from your previous post it sounds like your minimum idle rpm reference is set too high.

Here is the tune I currently have if someone see's something obvious....

Boy was I wrong. You should probably go back to stock and start from scratch. Your idle control is disabled above 800rpm with that max rpm reference at 800...don't do that. Put proportional airflow enable rpm and basically everything idle related back to stock and try it again. Will probably run better with stock settings initially...

[GHuggins]

This is just something for you to try. Although it is out of a 6.2 with a btr stage 4 truck cam with a stock stall, it should be pretty close for your 6.0 setup. I changed some of the O2 settings for the longtubes too.

If you still decide you want to run open loop at idle only, it's not hard to do - albeit not necessary and causes plenty of it's own problems - just use PE pedal and other activation settings...

You might need to tweak min air a touch, maybe even clean up vve a little more, but should be close for you. Some of the solutions for big cams with stock stalls while coming to a stop is in the trans tune and I'm in no way posting any of that or sharing it - just saying you might want to look at some basics there too.