E38 runaway idle when rolling

[CptFalcon]

Hi there, the vehicle in question is my 2007 suburban with a 370 and small summit stage one truck cam, its otherwise completely stock. I spent alot of time tuning the VVE and maf and have the truck pretty much running perfect. The idle is great, cold and hot starts are great, I honestly couldnt be happier, however it still has an issue when you put it in drive and begin rolling the idle will jump and the truck will take off, not anything crazy but it will lurch up to speed till you give it gas, its very annoying. On gen 3's I have cut the throttle cracker tables down and fixed this but on gen 4's all I can find is people saying to remove minimum airflow which I have done and it doesnt seem to help with this at all. Are there any idle adaptives on a gen 4 that are speed sensitive? It doesnt do this when sitting with your foot on the brake in drive its literaly only when you get around 2 or 3 mph. I will grab a log tomorrow and log all the idle pids I had no time today. I was thinking maybe its related to timing. Thanks




07 Suburban - Burb.hpt

[Cringer]

Hi there, the vehicle in question is my 2007 suburban with a 370 and small summit stage one truck cam, its otherwise completely stock. I spent alot of time tuning the VVE and maf and have the truck pretty much running perfect. The idle is great, cold and hot starts are great, I honestly couldnt be happier, however it still has an issue when you put it in drive and begin rolling the idle will jump and the truck will take off, not anything crazy but it will lurch up to speed till you give it gas, its very annoying. On gen 3's I have cut the throttle cracker tables down and fixed this but on gen 4's all I can find is people saying to remove minimum airflow which I have done and it doesnt seem to help with this at all. Are there any idle adaptives on a gen 4 that are speed sensitive? It doesnt do this when sitting with your foot on the brake in drive its literaly only when you get around 2 or 3 mph. I will grab a log tomorrow and log all the idle pids I had no time today. I was thinking maybe its related to timing. Thanks




07 Suburban - Burb.hpt

ECM 2196 is the speed component to adaptive idle. When adaptive idle is not active (either due to speed or touching the throttle), it will switch to using the high octane spark table rather than the idle spark table. Typically driving away is going to be caused by Min Final Air. You need to post a log.

[blindsquirrel]

The more tables you fiddle with the better it's supposed to run, right?

[CptFalcon]

ECM 2196 is the speed component to adaptive idle. When adaptive idle is not active (either due to speed or touching the throttle), it will switch to using the high octane spark table rather than the idle spark table. Typically driving away is going to be caused by Min Final Air. You need to post a log.

Ahh I see, I understand this is all just speculative without a log. I will have one tomorrow for sure. I just realized my idle spark table is commanding 20 degrees and then my HO is much higher in that same area. Once leaving adaptive idle the massive jump in advance seems like it could cause this? Should I bring them both more in line with one another just as a rule of thumb?

[Cringer]

Ahh I see, I understand this is all just speculative without a log. I will have one tomorrow for sure. I just realized my idle spark table is commanding 20 degrees and then my HO is much higher in that same area. Once leaving adaptive idle the massive jump in advance seems like it could cause this? Should I bring them both more in line with one another just as a rule of thumb?

Timing should be ok. I suspect the culprit is the VSS idle speed table. Make sure to add the Idle Desired RPM to your log.

[Alvin]

Post a log. But just a quick glance you have likely created a issue just messing with so many different tables.

The only things that should be changed are things you understand completely. If you make a change and don't get the effect you want. Put it back to stock. I'm not saying this lightly. I see so many issues caused downstream by a table not understood well but changed early on.

The torque model changes it appears you made could be the reason.

[CptFalcon]

Heres the log, any time you see the speed increase you should see whats happening.

24-11-14 09-47-32.hpl

[Alvin]

Looks like it's timing induced.

ECM 12614 is the culprit

[Cringer]

Heres the log, any time you see the speed increase you should see whats happening.

24-11-14 09-47-32.hpl

I made a bunch of changes here, try it. If it does not work, then get a log with more PIDs for idle air, spark, and adaptives.
07 Suburban - Burb - cringer.hpt

If you want to take a more minimalistic approach you can try addressing your over/under spark tables. They all have values in the zero rpm error column....and 12649 is backwards (pulling timing for an underspeed scenario).
over under spark.jpg

[CptFalcon]

I made a bunch of changes here, try it. If it does not work, then get a log with more PIDs for idle air, spark, and adaptives.
07 Suburban - Burb - cringer.hpt

If you want to take a more minimalistic approach you can try addressing your over/under spark tables. They all have values in the zero rpm error column....and 12649 is backwards (pulling timing for an underspeed scenario).
over under spark.jpg

Thanks Cringer, I flashed in the tune as you had it with no other changes and now it feels significantly worse. The truck would roll on its own before and now it will drive itself up to almost 20 mph no problem. I did another log. Website is being goofy and not letting me log in from my laptop.

[Cringer]

Thanks Cringer, I flashed in the tune as you had it with no other changes and now it feels significantly worse. The truck would roll on its own before and now it will drive itself up to almost 20 mph no problem. I did another log. Website is being goofy and not letting me log in from my laptop.

I had some strangeness with the forum this AM too. However, I am not expecting the truck to drive itself up to 20mph...that is even more strange. On top of the other idle PIDs mentioned, make sure to get Dynamic Air (g/s), VVE (g/s), Engine Torque, Idle Desired Airflow (g/s), and Idle Minimum Final Airflow (g/s). Hopefully all those will be available on your OS.

[CptFalcon]

I had some strangeness with the forum this AM too. However, I am not expecting the truck to drive itself up to 20mph...that is even more strange. On top of the other idle PIDs mentioned, make sure to get Dynamic Air (g/s), VVE (g/s), Engine Torque, Idle Desired Airflow (g/s), and Idle Minimum Final Airflow (g/s). Hopefully all those will be available on your OS.

Here you go, unfortunately a few of those werent available on my OS, its pretty bare bones. I also get a pretty big start up flare too now.

24-11-14 11-49-32.hpl

[Cringer]

Here you go, unfortunately a few of those werent available on my OS, its pretty bare bones. I also get a pretty big start up flare too now.

24-11-14 11-49-32.hpl

OK try this my man. Also, the truck as a 6.0L in it right?
07 Suburban - Burb - cringer2.hpt

[CptFalcon]

OK try this my man. Also, the truck as a 6.0L in it right?
07 Suburban - Burb - cringer2.hpt

Yes it has a 6.0 bored .030 so 370ci. I flashed that in and nothing changed, I opened a compare file to the first one and didnt see any differences, maybe I missed it?

24-11-14 16-55-26.hpl

[Cringer]

Yes it has a 6.0 bored .030 so 370ci. I flashed that in and nothing changed, I opened a compare file to the first one and didnt see any differences, maybe I missed it?

24-11-14 16-55-26.hpl

There are changes in the cringer2.hpt tune.
1vs2.jpg

[CptFalcon]

I see them now that was my bad. This truck still has self driving mode. Anything else I can tinker with on this?.

[Cringer]

I see them now that was my bad. This truck still has self driving mode. Anything else I can tinker with on this?.

One last set of changes. Not sure what else to try if this doesn't help.
07 Suburban - Burb - cringer3.hpt

It has the stock TB and the ETC scalar is still stock ([ECM] 2154)?

[CptFalcon]

The ETC scalar and TB are stock. However there is one thing I forgot to mention that I just remembered. The adaptive idle portion is copied straight from a stock LS9 tune. I was advised before I even started that it was better to use and more able to deal with the chop than the truck stuff. Not sure if this was a good move or not, should I go back to stock on that?

[Cringer]

The ETC scalar and TB are stock. However there is one thing I forgot to mention that I just remembered. The adaptive idle portion is copied straight from a stock LS9 tune. I was advised before I even started that it was better to use and more able to deal with the chop than the truck stuff. Not sure if this was a good move or not, should I go back to stock on that?

The LS9 adapts are G2G

[CptFalcon]

One last set of changes. Not sure what else to try if this doesn't help.
07 Suburban - Burb - cringer3.hpt

It has the stock TB and the ETC scalar is still stock ([ECM] 2154)?

THAT helped alot. You think it was too much idle timing? Everything feels pretty normal now, no more running away in gear. Thanks for all your help Cringer, you da man.