Help me avoid SD only mode? Another E38 idle thread

[TragicMike]

2007 LC9 5.3 DoD Delete
Truck Norris cam


It feels like no matter what I do Closed Loop wants to cut fuel at idle

Wideband always trends lean..

I have tried adjusting O2 sensor settings and cannot get it to comply.
side note: Integrator settings are not available on my ecu

I have tried cutting the VVE table at idle rpm.

Is there a way for me to trick this thing into cooperating, or should I just let it run lean?
My inexperience makes me afraid of SD only mode.

I will attach pics logs and tunes below once I get them sorted

[TragicMike]

EOIT settings: trying to "spray it safe"

EOIT- 12724.JPG


Idle logs:
idle 27 park.hpl
idle 27 gear.hpl

These are actually better than I am used to seeing.
Maybe acceptable.

Longer logs:
longer.hpl
0 to 70.hpl

Current tune:
idle vve minus 15.hpt

Stock tune:
11232023-AsFound minus DOD.hpt

[edcmat-l1]

If it's in closed loop how is it "running lean"?

And what makes you afraid of SD only? Although that cam shouldn't need to be run in SD only.

[ns158sl]

Your VVE is quite a bit off of the MAF as far as airflow.

[blindsquirrel]

SD is not open loop, it will run just peachy in closed loop with the stupid MAF disabled/removed.

[LS ROB]

SD is not open loop, it will run just peachy in closed loop with the stupid MAF disabled/removed.

Showing my ignorance here. I think i've read or been told that the MAF actually functions as the IAT sensor as well. I understand that disabled is, well, disabled; but does that also disable the IAT function if that's true?

[blindsquirrel]

Well you have to have an IAT sensor, so you have to add a non-integrated one. You can buy a breakout harness for just about any application to run a standard 2-wire LS1 style IAT, bunged into the intake system wherever you choose.

[LS ROB]

2007 LC9 5.3 DoD Delete
Truck Norris cam


It feels like no matter what I do Closed Loop wants to cut fuel at idle

Wideband always trends lean..

I have tried adjusting O2 sensor settings and cannot get it to comply.
side note: Integrator settings are not available on my ecu

I have tried cutting the VVE table at idle rpm.

Is there a way for me to trick this thing into cooperating, or should I just let it run lean?
My inexperience makes me afraid of SD only mode.

I will attach pics logs and tunes below once I get them sorted

I would put the o2 settings back stock for now and use the fuel trims to dial in light and mid throttle areas instead of using the wideband. I use my wideband for WOT fueling only but it is hooked up even when I am adjusting those idle, light, and mid throttle areas. It does idle a little leaner than one would think it should but it is actually happy there. Could be due to reversion...

[LS ROB]

Well you have to have an IAT sensor, so you have to add a non-integrated one. You can buy a breakout harness for just about any application to run a standard 2-wire LS1 style IAT, bunged into the intake system wherever you choose.

I see. Thanks brother!

[TragicMike]

If it's in closed loop how is it "running lean"?

And what makes you afraid of SD only? Although that cam shouldn't need to be run in SD only.

I have no idea why, but it has been persistent.

I am still unsure about a lot of things here... and disabling MAF seems like a big leap to me without being certain of VVE.

[edcmat-l1]

I looked at a log. It's in closed loop. It needs to be dialed in according to the trims. I'd ignore your wideband anything but WOT. I'd say unplug it for now until you're done dialing it in at part throttle. Then when you're ready to do the WOT plug it in.

You'll need to dial in the VVE whether you use the normal approach, fail the MAF, force SD, or the both at the same time deal.

[LS ROB]

i looked at a log. It's in closed loop. It needs to be dialed in according to the trims. I'd ignore your wideband anything but wot. I'd say unplug it for now until you're done dialing it in at part throttle. Then when you're ready to do the wot plug it in.

You'll need to dial in the vve whether you use the normal approach, fail the maf, force sd, or the both at the same time deal.

(like button)

[Allen Vos]

I'm sure you have read the thread i started a while back on E38 Idle as well, but in case you haven't , here is the link to it.

https://forum.hptuners.com/showthrea...ce-on-E38-Idle

I had the same issue you are having and edcmat-l1 was kind enough to modify my VVE table as it was way off as yours is as well.

It made a world of difference for my car and it idles way better now and a lot of the stupid hiccups and bugs have disappeared.

I still have work to do but I am a lot closer than I was before thanks to the help I have received here.

If you dial that VVE table in I'm sure that will fix a lot of your issues, then you can fine tune from there.

Make sure that minimum and start up airflow is set correctly as well. It helps a lot

I am hell bent on keeping MAF as well and don't want a SD only tune either so it will be interesting to see how we both make out.

I don't have a wideband yet but will in a few weeks so that will help me dial things in even better.

[blindsquirrel]

But WHY? Why MAF? What magic do you think it's doing? Maybe not always, but often, they just plain do everything better without the MAF. Better power, better driveability, better fuel mileage... intake plumbing is simpler...

[TragicMike]

But WHY? Why MAF? What magic do you think it's doing? Maybe not always, but often, they just plain do everything better without the MAF. Better power, better driveability, better fuel mileage... intake plumbing is simpler...

Having driven it around some with CL commanded off I actually agree with you.
However, this being my first tune I wanted to keep it simple.
That didn't exactly happen, but I feel more comfortable keeping it as close to stock as possible.

I'm sure you have read the thread i started a while back on E38 Idle as well, but in case you haven't , here is the link to it.

https://forum.hptuners.com/showthrea...ce-on-E38-Idle

I had the same issue you are having and edcmat-l1 was kind enough to modify my VVE table as it was way off as yours is as well.

I did see it, thank you.
As for my VVE table... it looks ugly compared to most that I have seen, but the truck likes it.
I have used the MAF/VVE at the same time method. Restarted multiple times. It always ends up looking similar.

[TragicMike]

Update:

I felt comfortable enough to return the truck tonight.
It will still need some tweaking over time, but I think it is close enough to be safe.

I am still not 100% sure why it wants to cut fuel at idle, but I have some observations:

My BRAF in Gear was quite a bit off. ~15%

Idle Airflow is definitely different (lower) than driving airflow.. at equal MAF frequencies.
which maybe makes sense because of speed induction or air temp?

This was skewing my scanner data sometimes by quite a bit.
I added an RPM variable to my MAF chart filter. (Vehicle speed variable might be better.)

Also selectively ignored some of the idle VVE numbers but I think I will bring them in line later.

As I said. Got it close enough for now.
Thank you all for talking it through with the newbie.

If anybody has the time I would still love to know more about the narrowband oxygen sensor settings.
Specifically the Min and Max Rich/Lean numbers and how they interact with the Bank1 and 2 switching voltages.

According to my wideband I'm running between -6% and 10% EQ error.
Stoich is set to 14 max so I think it will be alright.

Headed back to my original thread to learn about wideband PE tuning next.
2007-LC9-DoD-delete-Truck-Norris-Initial-Setup-Questions

[blindsquirrel]

Having driven it around some with CL commanded off I actually agree with you.
However, this being my first tune I wanted to keep it simple.
That didn't exactly happen, but I feel more comfortable keeping it as close to stock as possible.

Again, maybe you get it but I'm misunderstanding, but so many people conflate open loop with speed density and they are totally unrelated. Closed loop speed density works great. The MAF at best will not make it run worse, and it's fairly common that everything is better with no MAF. My 5.3 is properly tuned, both MAF and VE, and simply failing the MAF makes it almost one full second quicker from 0-60, and shows more than 60lb-ft more torque, AND picks up around 1.5 MPG in in-town driving. I will never put the MAF back on it unless for some reason I am selling it and returning it to stock.

[TragicMike]

I understand now.

I am one of those many people.
I really never considered going MAF-less and thought SD was just that.

More to learn.
Thank you.

[lsxjunkie]

But WHY? Why MAF? What magic do you think it's doing? Maybe not always, but often, they just plain do everything better without the MAF. Better power, better driveability, better fuel mileage... intake plumbing is simpler...

Interesting. What's your approach to SD tuning Fuel trims in closed loop. And PE open loop. Disable ltfts?

[blindsquirrel]

LTFT+STFT math