LLY hesitation

[LarryJewell]

I'm looking for some tuning input, Say i'm in traffic going about 40mph and I stab the throttle, there is a hesitation of like about 1 sec., then my truck slingshots forward. The truck is shifting awesome, has great boost, etc, I just would like for it to hammer from the start of the throttle jab without the hesitation, kinda like the LB7 does.

I'm thinking its one of the maf limiting tables in the fuel injection group causing this, B0751, B0752 or B0728.............I'm thinking they may be set to agressive possibly or is this just a LLY thing we need to learn to live with.

FWIW, I have tried all kinds of different settings with these tables.

Maybe the folks at EFI Live could open up a few more tables for the LLY's to play with
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[beach_33]

well for what it is worth larr i am tring to go through some of the lb7 tunes that i have to see if there are any tables that we are missing

[LarryJewell]

Possibly TBIQ, maybe the transition between 3/4 fuel to full fuel, maybe bring it together tighter.

[GMPX]

What I'd like to see in this thread is the current problem list the LLY tuners are having and then some responses if anyone has cured the problems with what we have available before I go hunting down tables that don't exist.

Cheers,
Ross

[abkimble]

Possibly TBIQ, maybe the transition between 3/4 fuel to full fuel, maybe bring it together tighter.

Have you logged vane position? Is it progressively getting worse with the large diameter compressor wheel you run in your cheetah? Did it change to a bit more lag compared to the last cheetah you had?

[beach_33]

well ross the biggest problem that i think most of us are having is the way when you punch the throttle the truck doesnt seem to go to full throttle instantly. instead it seems to ramp up. if you are crusiing around town and mash it, it downshifts, and you can literally count "one-onethousand" before it "rolls" in the fuel. Thats a good way to describe it...the LLY's dont fuel hard when you mash it; they "roll" in the throttle.

i dont know exactly where the fix for this would be. and as far as i know no one has come up with a fix. i think pat and brayden are the closest but still no actuall fix

[DURAtotheMAX]

here is some wierd LLY stuff.

It always seems to occur at ~3100rpm. Whats with the defuels.

SOmetimes it does it, sometimes it doesnt. Sometimes its a violent on/off/on/off defuel, as if im taking my foot off the pedal quickly, then mashing it again, then other times, it just lays down.

stupid LLY electronics.

ben

[Big D]

here is some wierd LLY stuff.

It always seems to occur at ~3100rpm. Whats with the defuels.

SOmetimes it does it, sometimes it doesnt. Sometimes its a violent on/off/on/off defuel, as if im taking my foot off the pedal quickly, then mashing it again, then other times, it just lays down.

stupid LLY electronics.

ben

I think you may have to log different pids to get a better picture of what is really happening. Your current pids work good for a LB7 but dont tell us the whole story for your LLY.

log
GM.ENGTQRREF_DMA
SAE.TP
GM.MAIN1Q_DMA
SAE.BARO
If available, GM.TRQ_FACT_DMA

This should reference your tables better and then you will be able to see what is being desired vs. commanded.
I find your pulsewidth interesting, frames 3246-3289. It does not seem to be consistent with rpm, TP or VSS.
If you could post up another log with the 3 additional parameters with some wot runs at various speeds showing down shift and "rolling" in one gear. I would like to see you tune to correctly reference the tables and give you a different set of eyes if something can be enhanced.

[DURAtotheMAX]

btw the only consistancy in logging is "driver demanded torque"

Ross, what tables/things INTERNAL to the ECM can affect/modify the "driver demanded torque" levels/limits?

Its not my pedal position sensor.

ben

[beach_33]

i think i see what you are talking about. i see that your mm3 bounces from 105 all the way down to 90mm3. mine does the same thing. i cant figure out why. i also had thought that when we where talking about the way the motor seems to stumble when you stab the peddle that maybe it had something to do with a peddle table that we dont have. perhaps some kind of limiter that doesnt let mm3 go to full on with in a certain amount of time .