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'08 LMM Tuners/High Idle

11K views 18 replies 7 participants last post by  rcfire5 
#1 ·
:gaah

I have been looking at tuners and weighing the pro's and con's for a while but have come up with two questions that I can't seem to get a clear answer on before I buy one. One was: can GM tell if you use a tuner on the LMM some say yes others say no (Is there ways to explain away any suspesions they have), and two: the high idle on my truck (for cold weather) kicks in under ten seconds after starting, I think this is way to soon for the high idle to be engaging, maybe after 45 sec - 1 minute but not under 10 sec, can tuners change this? The dealer says they can't yet another guy was in at the same time I was and he says his won't kick in until 4-5 minutes after it's started. What's the deal?

:peelout

Thanks in advance for your help

BDD
 
#2 ·
My understanding is that GM can tell if you use most tuners. However, according to what I have read, the only one they can't see is the Banks tuner. It somehow bypasses the ecm and doesn't leave a foot print.
All of that is from my hazy memory if someone knows the real answer I hope they chime in.

As for the high idle I will check mine tonight and report back.
 
#4 ·
Nate they can tell that the engine isnt operating within stock parameters, if the engine goes beyond the set RPM they can tell, if more fuel is being injected they can tell, they have the same thing as EFI live, they made the programming, so im guessing they can tell if something has been modified
 
#5 ·
Any tuning that increases power will be seen on LMM. When they do a warranty service they have to report Calibration ID Numbers and Verification Numbers from the Vehicle Information AND the Programming History screen as well as Transmission Data screen containing the Max Transmission Calc Engine Torque. If that comes up different or higher than stock, no warranty service.

The in-line tuners did not leave tracks because they were intercepting signals between the ECM and motor/FICM and commanding parameters instead of reprogramming the ECM and changing program parameters.

The high idle kicking on in 10 seconds and going to 1000 RPM isn't going to hurt anything. It's only 1000RPM.
 
#7 ·
The trans recording the max torque has nothing to do with how much actual torque the engine is producing. It all has to do with fueling references the ECM and TCM use to adjust how much fuel to use and how much fuel to cut based on driver input via the throttle.

Josh even an Inline tuner would show on the logs....
This is what I've heard too.
 
#6 ·
Josh even an Inline tuner would show on the logs....
 
#8 ·
I learn something new everyday. I always thought the max calc torque was what the ECM/TCM determined would be the input torque. Stock tuning never results in this being more than factory parameters. With a tuner it can exceed factory parameters.
 
#9 ·
thats why if you have a truck under warranty and want to save yourself some hassle, just get a backup ECM and run it on your truck periodically, that way it wont look funny if its only been run once a long long time ago
 
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#11 ·
Thanks guys for all the info. I'll look a little more into banks products. The crazy canucks comment about a second ECM, does anyone really do that and can that really work? It sure is creative.

An update on the high idle, it warmed up to 0 C (32F) and the high idle didn't come on for 35 seconds, there must be a sensor in play here but from my point of view it's working backardss (less time when warmer makes more sense). I'm looking for Factory service manuals for my 08 2500, does anyone have an option to the $250 GM manuals?
 
#13 ·
Thanks guys for all the info. I'll look a little more into banks products. The crazy canucks comment about a second ECM, does anyone really do that and can that really work? It sure is creative.

Yes you can do it, guys do do it, and yes it can really work, an LMM ECM is an LMM ECM, the best way is to have a log of your stock tune and loaded onto the "stock ECM" and then you can have the "tuned ECM" for the playing, when you need to take it in for service just put the "stock ECM" in the truck and you should be able ok, im not sure about the TCM however... anyone else chime in???

An update on the high idle, it warmed up to 0 C (32F) and the high idle didn't come on for 35 seconds, there must be a sensor in play here but from my point of view it's working backardss (less time when warmer makes more sense). I'm looking for Factory service manuals for my 08 2500, does anyone have an option to the $250 GM manuals?


The High idle is dependent on temperature, it may take longer to idle up when extremely cold because the engine may be waiting for the oil to start circulating before idling up. As for the manual, maybe check out EBAY?
:wave
 
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#12 ·
Mine seemed like more than 35 seconds. I did pay attention today to see what the delay was, but I did not time it.
 
#14 ·
Appreciation...

Thanks Britewhiteram (CCM#1). I saw another one of your posts that mentioned killerbee so I messaged him for more info and pricing.

This is my first diesel so I guess you could call me a diesel virgin. Bought my toy to pull the new camper (love pulling away from a light towing 9000lbs and watching the driver next to me slap their jaw shut in my side view mirror :haha. Plugs that glow but not spark, 2600lbs fuel pressure not 60 lbs, sounds like a hammers loose in the crank case, but torque out the "ying/yang".

:peelout
She's got 25k on her now and can't wait time she finally breaks in. Seems like when ever I try something new I lose mpg (going to the dealer for anything lowers my mpg to). So I'm on a steep learning curve. Make her perform but taking care of her at the same time.

Good info on this site, a lot of knowledgeable guys (want to be one someday so I can help others).

Thanks to all of you guys for your help and input.

BDD
:canada
CCM#34
 
#15 ·
Just so you know the High Pressure Common Rail injection systems on these engines actually produces pressure in the 26000-30000psi range, not 2600psi, even the old mechanically injected diesels produce pressures in the 8000-10000 range :thumbsup :canada

Also you may want to look at www.Kennedydiesel.com as i believe he sells tuned ECM's as well :happymugs
 
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#16 ·
Once again I stand corrected, thanks again for the info. I looked at Kennedy as well (good site and lots of info).


BDD

:canada :toytruck

CCM#34
 
#17 · (Edited)
COME ON NOW...Where does it stop!!!!

Well I hope some of you Diesel Guru's still look at this thread because I'm on information overload. I've been reading lots and have a bunch more questions but I'll keep these ones brief.

Tuning:
To tune I've read here that I need to get a programmer or another ECM that’s tuned, but I've also read here (in this thread) that the TCM needs to be considered as well so should it be changed out?:confused:

DPF: If you tuning do a DPF delete! (Well that just doubled the price for tuning an LMM) How does a piece of pipe, a fuel line cap and a connector that gives a steady reading back to the ECM = $1000 :thumbdown

EGR: I just saw a thread from Dirty Diesel with a pic of the egr port open...good golly molly how the hell did that engine run with all that build up. Is an EGR delete needed to? Or is this the result of running your truck "to easy". Right now I'm driving for fuel mileage cause the cold weather warm ups are gobbling enough fuel as it is.:wtf Should I honk on Bo-bo so I don't build up crap like that or drive easy to save on fuel?

Am I missing something else here, or am I on a tangent so far left that the rhubarbs in sight
 
#18 ·
LOL well ok i dont think you need to change the TCM, it controls the transmission, but if you do plan on tuning you should have your transmission built up

to delete the DPF the cost is basically that of a new exhaust, and there are exhaust makers out there who arent that expensive... you could delete the DPF for around $500-600(cost of a 4" mandrel bent single exit exhaust), and since you are planning on tuning i suggest a tuner that will disable the DPF system (EFI, PPE, Quadzilla) so you dont need any crazy fooling devices just the tuner

there are EGR block off plates that are about $10-25 availible from many sources(bought mine off ebay) and it just prevents the soot from getting back into the intake, and if you have a tuner you can disable the EGR valve as well...

IF you plan on deleting DPF and Blocking EGR you are probably not worried about your warranty as much, so you dont need an additional ECM

you could have a truck capable of low13's to high 12's with this list of mods
PPE hot +2 ET or EFI live ($900-$1300cdn)
Turbo back exhaust($500-$1500cdn)
transmission($3500-5000cdn)
egr block plate($10-$25cdn)
Fass or AirdogII($600-$900cdn)

for around $5000-$9000cdn roughly, would need some tie-rod sleeves, but they are about $250-300
 
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