LML vane position at idle

[catman3126]

Is there any way that anyone has found to get the vanes to stay open at idle on the LML? since there is no min and max table has anyone found another way to get it to stay open? Very strange that it will open right up in reverse at idle but not in forward gears. and if you bring the rpm up 50 off idle with the pedal in neutral it will open them up also. So i though well bump the idle up 50 rpm. no luck still closes them off.

[GMC-2002-Dmax]

2012 OS by any chance ??

:music_whistling_1:

[catman3126]

Nope 11'

[GMC-2002-Dmax]

Its possible to have them open on all 2011-2015 OS.

You have to get the right combination to get the vanes to stay open at idle.

The 2012 will every once in a while do that to me, but that is the only OS I have found to randomly do that.

[catman3126]

The right combination of switches? is that what your saying?

[catman3126]

What is the OS # of the 12' that will do that? I wonder if thats possible that is has a 12' OS in it?

[Chavez91]

My '11 will randomly do that to me too. But seems that after a few hundred miles on the tune after a reflash, it will always go to a rumble and sometimes it will rumble right off the bat. She has a personality... haha :nixweiss:

And its the right combination of "everything". These LML's are finicky.

[DURAtotheMAX]

Ive found its really random too....I finally figured it out to the point where it rumbles maybe 80% of the time. Then I ran out of time to mess with it, and the guy isnt local to me. Next time I get access to the truck Ill mess around with it again.

Ben

[catman3126]

OK thanks I'll get back on it. I bought an LML so I could get tunes developed for it lol so I have plenty of time to figure it out.

[blklmm]

yeah doesn't seem to be an easy way to do anything on these trucks lol I've experienced similar issues with vane pos but haven't had time to mess around till it was perfect

[catman3126]

well I got this issue ironed out, at idle it stays at 5% all the time now. sounds alot better and another thing thing I noticed is that the vanes do not go all the way to zero as soon as the boost comes up now either. I fixed the going to 0% at cruise speed awhile back and now they will stay at 10-12 % and only when in 5th gear lock up on my hot tune do I see 0% now.

[HeavyD]

Cat, Care to share how you got this accomplished? I'm working with my tuner now to get the same result on my '13. Feel free to PM me if you'd like. Thanks!!

[LMMPerrona]

well I got this issue ironed out, at idle it stays at 5% all the time now. sounds alot better and another thing thing I noticed is that the vanes do not go all the way to zero as soon as the boost comes up now either. I fixed the going to 0% at cruise speed awhile back and now they will stay at 10-12 % and only when in 5th gear lock up on my hot tune do I see 0% now.


I messed with this for a while. Set my position to 40% at idle. I saw no changes. After about 10 cal flashes, lol I noticed the Maximum VGT Actuator Duty Cycle, That thing was the one holding me at 89% all the time at idle. I changed it to 20% then logged and it was doing what i had set the VGT Position tables to.

[SASDakota]

Wouldn't maximum just be a limiter to how much it COULD close the vanes? That doesn't make sense that it was holding it closed. That sounds more like a minimum map.

[LMMPerrona]

Exactly... that's what I thought the whole time. I played with the position tables setting them at different values. nothing, til I set the maximum VGT. It worked.

[catman3126]

Theres another way. :good:

[LMMPerrona]

What's the other way? I would like to know

[SASDakota]

Are you sure the max table made it follow the vane position? Or did your change to the max table just mimick what you wanted to do?

Have you looked at your desired psi at idle? If you are commanding 1-2 psi idle, it will close the vanes until that happens.


I am just thinking logical through it, haven't tuned an LML.

[LMMPerrona]

You know what I didn't log everything. I was just concentrated on quieting down idle. So that's what I did for idle. Now that you mention that I will log to see if it follows the whole table.

[DURAtotheMAX]

I noticed the Maximum VGT Actuator Duty Cycle, That thing was the one holding me at 89% all the time at idle. I changed it to 20% then logged and it was doing what i had set the VGT Position tables to.

Isnt that going to limit overall vane position though? Like not allow full closure of the vanes during exhaust braking or high-idle/heater performance?

In playing around with vane position tables, I was able to get it to stay open at idle sometimes, but not all the time. I ran out of time to play with it and dont have easy access to the truck anymore. But I never messed with B1202 because I figured it would limit overall max allowed vane position at any time.

[LMMPerrona]

Hmm. That sounds right.. I just got excited and left it like that but when I get a chance I will see what it's actually doing

[catman3126]

Isnt that going to limit overall vane position though? Like not allow full closure of the vanes during exhaust braking or high-idle/heater performance?

In playing around with vane position tables, I was able to get it to stay open at idle sometimes, but not all the time. I ran out of time to play with it and dont have easy access to the truck anymore. But I never messed with B1202 because I figured it would limit overall max allowed vane position at any time.

That's what I figured too. I think it would be similar to messing fpr duty cycle. It cause surging or low rail pressure.

[DURAtotheMAX]

I dont have a truck to try it, but maybe make sure all of the desired boost tables are equal to or lower than the actual atmospheric pressure....

For example, B0727, says that in the idle RPM range, the maximum boost that can be commanded is almost 10psi over standard atmospheric pressure.....what does the ECM do when it wants the actual boost to meet the desired boost? It closes or opens the vanes....

[LMMPerrona]

You guys are right. I'm not making commanded boost. Hmm. I'll have to keep hunting to see how I can quiet down at idle.

[catman3126]

I dont have a truck to try it, but maybe make sure all of the desired boost tables are equal to or lower than the actual atmospheric pressure....

For example, B0727, says that in the idle RPM range, the maximum boost that can be commanded is almost 10psi over standard atmospheric pressure.....what does the ECM do when it wants the actual boost to meet the desired boost? It closes or opens the vanes....

I didn't have much luck with this. it may help but theres a combo of switches that need to be coreect to get it to do what you want.

[LMMPerrona]

I'll keep playing with it when I get a chance. Appreciate all the help.

[SASDakota]

I'll keep playing with it when I get a chance. Appreciate all the help.

Maybe post your file and I can see if anything sticks out. I haven't tuned an LML yet, just LBZ and LMM but maybe a 2nd set of eyes would help?

[DURAtotheMAX]

Maybe post your file and I can see if anything sticks out. I haven't tuned an LML yet, just LBZ and LMM but maybe a 2nd set of eyes would help?

LML turbo control is significantly more complicated than 2004.5-2010 LLY/LBZ/LMM.

[SASDakota]

Gotcha. Who doesn't like a good challenge? :grd:

[jgooch1548]

Did anyone Ever get this issue Ironed out?

[Mitco39]

Ive tried and with the tables we have access to I could not get it to do what I wanted. I know Kory is doing them and I know H&S does it, I am assuming there is extra tables in there (havent had time to look through mcc to see if they are listed with their software).

[JoshH]

Here we are 5 years and some months later from the original post, and I have a 2012 I’m trying to get to keep the vanes open at idle. You can barely touch the throttle (not even enough to raise the engine RPM), and they will open right up to the open loop position table settings. Also, you can put it in reverse, and they will open but close in drive. It doesn’t make any sense to me. I could use some pointers if anyone has some guidance to help.