4 second delay on new motors?

[markislive]

Hey guys i've read a few reviews and heard of other folks talk about a 4 second power delay on the new GM motors. Anyone know what this is? Anyway to crack it with HPTuners? The reason for my concern is the lack of bottom end on my truck which is supposed to be rated @ 417lbs Tq..... I'm 2wd and was hoping for a smoke show.... My midrange and topend is awesome but comming out of the hole just sucks, it's gotta be PCM related "I hope".

I have also "heard" this has something to do with the amount of time it takes to go into open loop or start using "PE" after mashin the throttle...some say it's there for fuel economy

Any leads idea's or tip's would be greatly appreciated!

Some even say it can be removed with a handheld programmer...

Here are a few links....

http://www.autoblog.com/2007/01/24/t...munds-comparo/

http://jalopnik.com/cars/question-of...ers-242958.php

http://www.titantalk.com/forums/war-...tec-max-2.html

http://www.gminsidenews.com/forums/a...p?t-44685.html

[kindaslo]

torque management = 0

should solve your problem, i did it on my 2007 yukon, and have not noticed any ill effects after 6 months of driving it this way.

Even with tm turned off, the truck still has no guts from a stop fyi it's tough to get 7K lbs moving..

[Bill@HPTuners]

There is a power enrichment delay that will keep you at stoich for several seconds even at wot. just set the delay's to 0 & use your TPS vs. rpm enable table to set it to a reasonable turn on point.

[markislive]

There is a power enrichment delay that will keep you at stoich for several seconds even at wot. just set the delay's to 0 & use your TPS vs. rpm enable table to set it to a reasonable turn on point.

Thanks very much for the reply Bill...where can I find this "TPS vs. rpm enable table" TPS means "throttle postion sensor" right? My tune is posted up top...do you see it or am I just blind?

[Bill@HPTuners]

Engine-fuel control-power enrichment-hot power enrich enable tps threshold vs. rpm

[markislive]

All rpm values are set to 87.......

[Bill@HPTuners]

those numbers mean nothing if theres a time delay

Like I said set your delays to 0 & use the Tps vs. rpm as your reference

[Texsrt4]

interesting, the nissan should weigh more and have about the same torque. what gear ratio are you running? sounds like there is somthing in the tune that is reducing your off the line launch...or those massive wheels (80lbs per corner SERIOUSLY hinder accelaration)...either way figure it out for me, i tune my sierra this coming weekend

[markislive]

those numbers mean nothing if theres a time delay

Like I said set your delays to 0 & use the Tps vs. rpm as your reference

Ok Bill, I am still learning...do you see any PE delay from this screen shot or should I be looking at something else?

Please let me know if there is any room for improvement....Does MAP "manifold air pressure" matter a whole bunch with delay?

[markislive]

interesting, the nissan should weigh more and have about the same torque. what gear ratio are you running? sounds like there is somthing in the tune that is reducing your off the line launch...or those massive wheels (80lbs per corner SERIOUSLY hinder accelaration)...either way figure it out for me, i tune my sierra this coming weekend

This one is supposed to weigh 5,250 according to GM. My Nissan weighed 5,150 "crew-cab" Tq was 375 to the tires NA! Well shit here is a dyno.....I just miss the low end. on my Titan. I have no more "nutz" LOL! I own a 6.2L where's my nutz?

[Bill@HPTuners]

Ok Bill, I am still learning...do you see any PE delay from this screen shot or should I be looking at something else?

Please let me know if there is any room for improvement....Does MAP "manifold air pressure" matter a whole bunch with delay?

A scan log with that file would be helpful, while logging commanded afr to determine how much of a delay your seeing

Otherwise we're all just guessing.

[markislive]

A scan log with that file would be helpful, while logging commanded afr to determine how much of a delay your seeing

Otherwise we're all just guessing.

Here is my latest capture.....I did a quick WOT run to 96mph....I didn't notice a huge delay from the time where I mashed the gas till the time my commanded AFR went 12.8-9ish!...i probably just have a peice of crap! My wideband comes in later this week i'll tweak my "real" AFR then...

[BBA]

TM does not fix it on TBSS. The tunes I did made it better but I really didn't fix it until I bumped up the Airflow-Cylinder Charge Temperature Coeff Filter settings in the four lower settings. I made them stepped a lot closer to the value of the higher range settings...made a freaking huge difference.

[markislive]

TM does not fix it on TBSS. The tunes I did made it better but I really didn't fix it until I bumped up the Airflow-Cylinder Charge Temperature Coeff Filter settings in the four lower settings. I made them stepped a lot closer to the value of the higher range settings...made a freaking huge difference.

Hey BBA...U sayin the TBSS is kinda a dog outta the hole in stock form also? I woulda never thought that motor would have had problems off the line...care to share your b4 and after tune tweaks?

[5_Liter_Eater]

Two things that would affect your PE kicking in right away as Bill has tried to explain:

- Engine, Fuel Control, Power Enrich, Delay RPM. Set this to 0. Stock is 5000 I think for your truck so it will not command whatever you have your PE set to until after 5000 RPM.

- Engine, Fuel Control, Power Enrich, Enrichment Rate. Max this out at 2.

Looks like you've already done this from your screenshot.

I also don't like how the trucks don't enable PE until 87%.

[markislive]

Hey 5 Liter Eater, Thanks for the reply...So I will not go into PE mode until the throttle is mashed down 87%....What would be a good number to try that wouldn't be to aggressive?

[5_Liter_Eater]

Correct.

Here is my PE Enable TPS table.

[markislive]

Sweet ...I'll have to give that a try.

[kenny c]

Correct.

Here is my PE Enable TPS table.

Sweet! I looked at that table, but didn't see any need to change it because I obviously misunderstood what it did. I was waiting until the next release to see if it had the "cold PE enable" table.

Do the gen IVs use only the hot table? Guess I'll be trying this tonight!

[kenny c]

Hey BBA...U sayin the TBSS is kinda a dog outta the hole in stock form also? I woulda never thought that motor would have had problems off the line...care to share your b4 and after tune tweaks?

Pulled this from the help file...

Cylinder Charge Temperature
The VCM (depending on type) may use various methods to determine cylinder charge temperature. It either simply uses the IAT sensor value or it uses a complex estimation model based on a combination of IAT, ECT and airflow to account for aircharge heating from the intake manifold. The resultant temperature is used for speed density airmass calculations.

Complex Temp Model: This chooses either the simple IAT or complex temperature estimation model.

Charge Temp Bias vs. ECT: This table determines how much the charge temperature is biased towards the ECT or IAT. Higher numbers bias the resultant temperature towards ECT (generally higher bias at lower airflows. ie. the air has longer to be heated by the manifold at low airflows).

Charge Temp Filter vs. Airflow: This table determines the rate at which the temperature moves to the new bias temperature. At low airflows the rate of temperature change is slower than at high airflows.

How much of an impact do these tables have?