LLY: my truck's weird issues...revisited...again

[duratothemax]

Im just trying to figure out why GM did some things the way they did, like why in the TLIQ table, do they put the 3000rpm column at 122 mm3 when none of the other mm3 tables even go that high, the main rate table only goes to 100!

Basically, I think nobody really understands how all the torque limiting works, and most importantly, how it all relates to eachother and correlates with other parts of the tune.

They just whip through the tune maxing out every "ft lbs limit" and "mm3 limit" value they see without even having the slightest idea what they are changing. Im going back to the beginning and trying to understand/figure out the basics because no one seems to really know the answers to my "basic" questions... No offense intended to ANYONE in this thread, its just that in searching everywhere I cant find any concrete answers.

ben

 

[TrentNell]

Im just trying to figure out why GM did some things the way they did, like why in the TLIQ table, do they put the 3000rpm column at 122 mm3 when none of the other mm3 tables even go that high, the main rate table only goes to 100!

Basically, I think nobody really understands how all the torque limiting works, and most importantly, how it all relates to eachother and correlates with other parts of the tune.

They just whip through the tune maxing out every "ft lbs limit" and "mm3 limit" value they see without even having the slightest idea what they are changing. Im going back to the beginning and trying to understand/figure out the basics because no one seems to really know the answers to my "basic" questions... No offense intended to ANYONE in this thread, its just that in searching everywhere I cant find any concrete answers.

ben

I cant speak for every tuner , nor am i a tuner other than my own race truck, friends or trans custommers but i have spent alot of time with base torque and TLIQ in the name of shift quality and getting transmissions to live under high power and atleats on the LB7 i know how every limmiter table works and can tune to get the exact amount of defuel i request , and also i still use the limmiter tables even on my race tune. the bit of tunning i have done on LLY's it works the same just a few more tables in the mix and some other limmiter tables that co-exsist with thew logic the ecm uses .

 

[GMC_2002_Dmax]

I get asked quite a bit by my customers if I rescale the MAF sensor for twins, for airbox mods, for any reason and the answer is NO.

MAF is used to limit fueling based on the B0751 and B0752 tables in the LLY ecm file. This is also changed from the factory for a cylindrical or square air box because the stock MAF, stock BOOST and other parameters are monitored closely in a stock tune for many reasons and will throw you into limp if it goes out of range.

Ben, you have no airbox, you have two turbos, the location of your MAF sensor is in a very different place than it would normally be.

There is a way around it, if you have time stop by and I'll help you resolve the issue.

:thumb:

no Tony, I have both tunes right in front of me (stock LLY for the square airbox and stock LLY for the LBZ airbox) and B0751 and B0752 are identical between the two.

The only difference in the two tunes is B0201.

ben

You did not read what I wrote or maybe I did not explain it correctly or you did not understand what I said. I said all MAF does is limit fueling based on the air flow into the engine, it is there so that the fueling request is limited by the ecm until it sees enough air going into the motor, if you see 66 lbs of air a minute going into the motor at WOT on a log then unless you are coding for MAF out of limit and you didn't alter the limp tables then you won't see a defuel.

So when you log MAF at WOT with a defeul tell me what the MAF Flow shows, if it is showing 66 lbs you lose.

I'll see you at the track on April 17th..............

Oh, BTW some of us do understand what the tables do and mean, even if we don't share that information.

 

[dmaxfireman]

ben you've got voice mail and text call me back might have a solution to your maf issue

 

[duratothemax]

I said all MAF does is limit fueling based on the air flow into the engine, it is there so that the fueling request is limited by the ecm until it sees enough air going into the motor,..

I realize thats all efilive says it does, but im convinced it does a lot more than that. Im sure on the LB7 thats all it does, but the LLY is a lot more complicated and sometimes not predictable, you've admitted that to me before.

if you see 66 lbs of air a minute going into the motor at WOT on a log then unless you are coding for MAF out of limit and you didn't alter the limp tables then you won't see a defuel.

So when you log MAF at WOT with a defeul tell me what the MAF Flow shows, if it is showing 66 lbs you lose..

Why does it sometimes do it with a completely stock tune?

 

[duratothemax]

also, does someone want to explain to me why in a stock tune, the minimum vane position is 6%

Yet I have logged it commanding 4% at WOT.

A disconnected MAF will cause issues on an LLY, even though every limp mode table is maxed out and all DTC's disabled

 

[duratothemax]

there is no reason an LBZ-intake stock tune should defuel and an LLY-intake stock tune should not.

If you do the math, there is about .1 difference in g/cyl at 3100rpm....

or does EFILive cap it at 66.14 lbs/min when GM actually programmed the LBZ-intake tune higher than 66.14? So we cant really see what the LBZ-intake tune actually goes to?

ben

 

[TrentNell]

there is no reason an LBZ-intake stock tune should defuel and an LLY-intake stock tune should not.

If you do the math, there is about .1 difference in g/cyl at 3100rpm....

or does EFILive cap it at 66.14 lbs/min when GM actually programmed the LBZ-intake tune higher than 66.14? So we cant really see what the LBZ-intake tune actually goes to?

ben

Ben if you can shoot me an email of one of your old logs and a tune you have tried to fix it with , I know better men than me had attemted to fix it i am just curious is all compared to what i think would fix it

email is

[email protected]

 

[GMC_2002_Dmax]

I told you I had one truck that would limit fueling to 88mm3 at WOT, it was a twinned LLY without a VVT charger, I changed the OS to the same OS# from a different LLY truck and it solved the problem with no other changes.

In your case I believe you are simply overlooking something in the tune.

LLY's are a little different, but I have not seen an LLY with the problems yours have.

 

[duratothemax]

I told you I had one truck that would limit fueling to 88mm3 at WOT, it was a twinned LLY without a VVT charger, I changed the OS to the same OS# from a different LLY truck and it solved the problem with no other changes.

In your case I believe you are simply overlooking something in the tune.

LLY's are a little different, but I have not seen an LLY with the problems yours have.

which OS # gave you the trouble?

How am I overlooking something if it sometimes surges with a stock tune. :

 

[duratothemax]

there are a lot of experts that seem to have this all figured out, yet no one can answer my question about how the ECM calculates/references/uses torque values when not in a "torque limiting" mode (ie, during a shift)

the torque values (if you log them) change all around while driving, not just during shifting.

How/where is it getting these values from. According to EFILive, base torque and TLIQ are only active "during torque limiting" (ie, during a shift)

base torque and TLIQ seem like a chicken/egg thing. Which table takes prescidence, etc... Which table determines what the other one will reference?

I was a beta tester for efilive when duramax tuning as a whole first started (december 05), yet back then it seems like we never really took the time to understand how the ECM works as a computer/mathematically......we just saw "ooo something that limits fuel, *delete* or *max out*.

People can claim they've got it all figured out and know exactly how the ECM works, how it calculates things, how it references things, how the computer engineering behind it works, but I dont completely believe any of it. Because someone made a tune that somehow makes big power, doesnt necessarilly mean they understood WHY it worked the way it did....they just used a "brute force" method of tuning and took hundreds of thousands of shots in the dark until they came upon a combination that worked...thats NOT the same as actually understanding the engineering/workings of it. If that makes sense.

 

[duratothemax]

Ill let the experts explain whats going on here, cause I have no idea. :

 

[TrentNell]

there are a lot of experts that seem to have this all figured out, yet no one can answer my question about how the ECM calculates/references/uses torque values when not in a "torque limiting" mode (ie, during a shift)

the torque values (if you log them) change all around while driving, not just during shifting.

How/where is it getting these values from. According to EFILive, base torque and TLIQ are only active "during torque limiting" (ie, during a shift)

base torque and TLIQ seem like a chicken/egg thing. Which table takes prescidence, etc... Which table determines what the other one will reference?

I was a beta tester for efilive when duramax tuning as a whole first started (december 05), yet back then it seems like we never really took the time to understand how the ECM works as a computer/mathematically......we just saw "ooo something that limits fuel, *delete* or *max out*.

People can claim they've got it all figured out and know exactly how the ECM works, how it calculates things, how it references things, how the computer engineering behind it works, but I dont completely believe any of it. Because someone made a tune that somehow makes big power, doesnt necessarilly mean they understood WHY it worked the way it did....they just used a "brute force" method of tuning and took hundreds of thousands of shots in the dark until they came upon a combination that worked...thats NOT the same as actually understanding the engineering/workings of it. If that makes sense.

Ben , i had a complete paragraph typed out on exactly how i have tested the base torque table , and the TLIQ and what i have found and how i figured out what little i know from 100 plus logs from several high power trucks including my own , which led to finding which limiter tables take priority , but since you are convinced that know one knows and we are all idiots but you , and are not even willing to respond to my attempt to help and even send me a log then have fun with your defuel :thumb:

 

[Mike_S]

Just throwing this out there...turbulence at the MAF sensor maybe? Thats some weird shit going on there...things are bouncing all over the board...

 

[duratothemax]

My personal favorite:

seriously, how does one explain that ^

 

[duratothemax]

Trent you have a PM.

 

[GMC_2002_Dmax]

which OS # gave you the trouble?

How am I overlooking something if it sometimes surges with a stock tune. :

IS YOU TRUCK STOCK ?? If yes move onto to you missed something, if no do not pass go and go straight to jail.



You are missing a table, you are having a "something" go out of range or you missed a related table.

But since we don't know anything then I am leaving you to figure it out yourself. I have hundreds of trucks out there and not one of them LB7 or LLY have any issues with fuel reduction, timing being pulled, etc.

I told you I would help you, but you seem to only want to argue with everyone and I don't have time to argue.

If you change your mind you know how to find me.

:thumb:

 

[LarryJewell]

Subscribing

 

[Killerbee]

I looked through this thread and I have examined literally thousands of logs, not one with twins. However, many relationships won't change. You have a stock tune with a non-stock configuration, so there isn't any particular validity to any logic you are trying to convey. Tony and others are trying to say this. Also you indicate that the ECM coding is something other than stock. Maybe that is relevant.

2 cents of advice. Defuel logs need to include maxtorque if they are going to mean anything. I don't think you have a MAF concern here at all. Your defuel is sudden and precipitous, the type that accompanies torque commanded defuel, or limp fueling...not MAF fuel limiting.

Perhaps, if anything, some things you stated earlier are complicit. Is it staying locked up? Log some tranny parameters and especially torque. If your torque curve is spiking, you can limit the scope of your search. Take a deep breath, remember you may have to repeat yourself from time to time.

 

[duratothemax]

I looked through this thread and I have examined literally thousands of logs, not one with twins. However, many relationships won't change. You have a stock tune with a non-stock configuration, so there isn't any particular validity to any logic you are trying to convey. Tony and others are trying to say this. Also you indicate that the ECM coding is something other than stock. Maybe that is relevant.

2 cents of advice. Defuel logs need to include maxtorque if they are going to mean anything. I don't think you have a MAF concern here at all. Your defuel is sudden and precipitous, the type that accompanies torque commanded defuel, or limp fueling...not MAF fuel limiting.

Perhaps, if anything, some things you stated earlier are complicit. Is it staying locked up? Log some tranny parameters and especially torque. If your torque curve is spiking, you can limit the scope of your search. Take a deep breath, remember you may have to repeat yourself from time to time.

Ill have to find the logs, but Ive logged the trans and torque values.

DRIVER DEMANDED TORQUE. Thats what jumps around; ive asked people what the ECM references driver demanded torque to internally, but havent gotten any answers.

(now before someone smart comes in and says "well its something from the accelerator input, did you log your TP% maybe you have a bad APPS", NO thats not the problem)