6.0 ls surigng/ stalling

2006 silverado 6.0 sloppy stage 2 cam with supporting mods i.e push rods valve springs head studs ect. 3200 stall torque converter from jeggs, after the install of the torque converter and swapping the transmission for a rebuild one, the truck started surging and at times dying out. Ive since spaced out the torque converter to the right specs and made the problem much less apparent. ive tired tuning it myself and have a few things changed in the tune None the less the problem is still happening, any help would be appreciated.
Attachment 155185
Attachment 155186

Temporarily disable idle over speed and under speed error (set all zeros), see what it does. That can wildly vary timing making idle tuning a hassle. This advice is without even looking at your files.

The VE doesn't look like I think it should with that cam.

The STIT is a bit positive. you usually get a little safer results tuning the BRAF table so that the STIT and LTIT are slightly negative.

And the base idle timing is too high. If the engine idles best at 24 degrees.. Well center the idle tuning around 18 or lower even. What this does is allow you to run the timing up to 23 degrees or more in case of an idle dip/ stall. You want some reserve torque.


unrelated to your post but important. This is lean at WOT and there is a knock sensor code which defaults to max retard in PE.

Quote:

---

Originally Posted by Alvin

The VE doesn't look like I think it should with that cam.

The STIT is a bit positive. you usually get a little safer results tuning the BRAF table so that the STIT and LTIT are slightly negative.

And the base idle timing is too high. If the engine idles best at 24 degrees.. Well center the idle tuning around 18 or lower even. What this does is allow you to run the timing up to 23 degrees or more in case of an idle dip/ stall. You want some reserve torque.


unrelated to your post but important. This is lean at WOT and there is a knock sensor code which defaults to max retard in PE.

---

This is a new thread based on an old problem.
https://forum.hptuners.com/showthrea...talling-6-0-LS

Fuel trims indicate the shape of the VE curve is more or less correct. There are many things that affect VE besides the cam.

Idle spark was set high due to converter drag. Need reserve torque, sure, but still need torque in the first place to idle. Putting it at 18 made any slight dip cause a large effect. Now that the converter has been setup, 18 will be revisited.

Quote:

---

Originally Posted by SiriusC1024

Fuel trims indicate the shape of the VE curve is more or less correct. There are many things that affect VE besides the cam.

---

My experience tells me that VE table isn't in the correct shape.

Perhaps revisit those low load low RPM areas with a wideband. Do you remember me discussing this a while back? GEN 3 fuel trims are too slow to catch small pockets in the VE table. This looks like a perfect example of this.

All of these P59s posted recently don't look like they're setup correctly as far as idle, return to idle, etc. They're a bit different. They take some different strategy. Even milder cams can send these things pretty wonky. Using the stall saver is not the right approach. Most of the ones posted don't have the rolling idle setup properly, even though it looks like y'all are trying to use it.

As Alvin said the VE just doesn't look quite right but in my opinion is only part of the problem. I'd suggest dialing it in WITHOUT changing the injector timing THEN change your timing and see what it does down low.

Fix the KS problem. Log with this.

I don't use rolling idle or stall saver.

Quote:

---

Originally Posted by SiriusC1024

I don't use rolling idle or stall saver.

---

Stall saver is setup in these already. I start with zeroing them out.

On this one the rolling idle is not setup. That was a general comment as a lot of the recent ones are kinda half assed setup for rolling idle.

I take it for granted that with higher idle the factory stall saver strategy doesn't come into effect.

Quote:

---

Originally Posted by SiriusC1024

I take it for granted that with higher idle the factory stall saver strategy doesn't come into effect.

---

Ideally it shouldn't. But in cases where the idle does want to dip it'll cause flaring. I'd rather it not flare after the dip and just try to manage it from not dipping. The stall saver exacerbates the situation.

Loaded this tune onto the truck, reversing out of driveway it stalled in beginning of log. Seems like the truck stalls more in reverse and more when its going downhill. Knock retard popped up near wot in a pull but definitely much better than before hand. Do you think this problem is soley tune related or could there be something mechanically wrong?
Attachment 155304

I just solved this issue on my truck. Luckily ive only had this issue on one vehicle out of several hundred and that was the first time ive enabled rolling idle. Something that does help is setting the idle adaptive airflow-min ingear/acoff parameter to 0 and adding a slight amount extra to the braf. The truck will adapt airflow sitting still but the extra airflow is there anytime you are moving. A smooth transition in the idle spark-drive table will help with the sudden torque loss when returning to idle speeds.

Alright see what this does.

Sirius, here is a idle spark-drive table that should smooth the return to idle. Worth a try to see if reducing the spark at higher rpms will help. That is a big jump from 3x* to 18*. Have you noticed the surging causes loss of vacuum which translates to more calculated airmass with lower spark advance?

Fixing my issue i had to realize that what the pcm was calculating was false and not preventable but there are ways to reduce the effect.

I did notice the transition. I increased BRAF and underspeed spark. As far as what you're talking about, I decreased the transition between the idle and base spark table. On the other side, I added airflow to throttle follower and cracker to make the transition less abrupt.

That is a good idea you have. The reason I went with my set of changes had to do with the stall at 8:58. It was already on the idle table there. There are a few variables at play, and if this doesn't improve I'm not going to continue along the same route of throttle cracker/follower. Idle spark truncation, as you suggested, would be next.

Let's not forget edcmat-l1's suggestion of restoring injection timing to stock. I've had to resort to this on a few before.

Please start logging TPS and injector pulsewidth.

This is just one reason i recommend dbc on gen 3 swaps. Not to mention the throttle body choices grow even if they have their own problems. The e38 has enough tables that this isnt a issue. The only issue i have on the e38 is oscillating idle in park which is quickly solved by relaxing the idle airflow integral table.