First time Duramax LLY Owner with Questions - Page 3

BigBlueGMC · 10-26-2009, 09:05 AM

Quote:

Originally Posted by midieselguy

JC1843 was asking the same questions I was thinking. I went from a chevy 454 to the LLY like you bought about 1-1/2 years ago and have had a smile on my face ever since. My truck pulls a 9,000 lbs load on flat ground like its not even there. You notice it under acceleration but you can tell the truck could handle twice as much. When pulling grades, did you make sure your tow/haul switch was on? This will prevent your truck from gear hunting while pulling grades. You can also shut the OD off and lock in 4th if you notice that's where the truck would like to run.

When I hit a grade, I slow the truck down to 60-65 and disable OD. Truck then pulls the grade without a sweat.

I agree that the IOH kit is an excellent improvement but it didn't give me much more pulling power, just reduced temps while pulling.

I hope this helps, I think you might be expecting too much from the truck. 9,000lbs is some weight, you'll feel it back there, but I bet your diesel will run circles around that old 6.0.

I just noticed your post. I didn't take it out of overdrive because I heard the Allison adjusts automatically so to speak.
That may have helped! I did try the tow/haul mode on a few of the inclines and noticed a slight difference, with cruise control on and set to 68, it did seem to pull up the incline a little better, but the rpms still jumped from 2000 to around 2700 or 2800 until I reached the top of the incline.
Maybe I just need to get to know the truck better and adjust my driving habits, been towing with gas engines for a long time, maybe an adjustment is needed on my part!!!

RedBowTies88 · 10-26-2009, 09:09 AM

Quote:

Originally Posted by BigBlueGMC

I just noticed your post. I didn't take it out of overdrive because I heard the Allison adjusts automatically so to speak.
That may have helped! I did try the tow/haul mode on a few of the inclines and noticed a slight difference, with cruise control on and set to 68, it did seem to pull up the incline a little better, but the rpms still jumped from 2000 to around 2700 or 2800 until I reached the top of the incline.
Maybe I just need to get to know the truck better and adjust my driving habits, been towing with gas engines for a long time, maybe an adjustment is needed on my part!!!

true....it is a little different from driving a gas engine..

on another note..the egr delete.block will help with inclines...mine downshifts much less since i blocked it..

BigBlueGMC · 10-26-2009, 09:24 AM

Quote:

Originally Posted by Killerbee

You have defined thermal feedback. Lots to understand.

http://members.cox.net/td-eoc/LLY%20...verheating.pdf

I read the article and from what I could understand I should get the LBZ MP, a true cold air intake, and efilive whatever that is!
I'll check out the efilive, is it an effective mod?
Did I miss anything?

RedBowTies88 · 10-26-2009, 09:27 AM

Quote:

Originally Posted by BigBlueGMC

I read the article and from what I could understand I should get the LBZ MP, a true cold air intake, and efilive whatever that is!
I'll check out the efilive, is it an effective mod?
Did I miss anything?

you just need a new mouthpiece dont worry about anything else yet man..

EFI Live is an awesome thing...but there is tons to understand with it and you dont need it yet..

its more or less a tuner....its the best one there is...its also the most complicated. its a great thing to have but not needed and certainly not urgent...your just starting out so i would worry about that down the road more

**Killerbee** · 10-26-2009, 09:29 AM

EFILive is just a piece of software. It is every bit as bad, or good, as the skill level of the person doing the key entry.

**Killerbee** · 10-26-2009, 09:33 AM

Quote:

Originally Posted by BigBlueGMC

I read the article

All 4 of them?

BigBlueGMC · 10-26-2009, 09:37 AM

Killerbee, All four of what?

MaddMax · 10-26-2009, 09:39 AM

Quote:

Originally Posted by BigBlueGMC

Hi,
Let me start by saying I never owned a diesel truck before, so I don't know what to expect from it or what driving habit adjustments I need to make now that I own one!

I just bought a 2004.5 GMC Sierra SLT 4x4 crew cab with an 8ft bed!
It has the Duramax Allison combo.
It has 110K miles and seems to drive like new, except when towing!

I picked it up with my 2003 Chevy 2500HD (6.0 gas) 120 miles away!
I hooked the trailer to my new GMC diesel and loaded my 2500HD on the trailer.

I found that on level grades it pulled the trailer fine, but when on the highway and dealing with long inclines, I felt it did a terrible job of pulling on the inclines! Isn’t this where a diesel is supposed to shine!!!

Ok, with that said I checked the internet and found all kinds of articles slamming the LLY engine.

I also found a lot of articles and ads for an LLY Induction overhaul kit, True cold air intake, the Duramileage EZ tuner and many other upgrades. My pockets are only so deep so the big question is:

Are there design flaws with the LLY that should be addressed first and if so which ones are most important and which ones will give me better towing performance and a boost in HP and correct the things GM should have done in the first place???

Any and all comments would be appreciated!
I know there is a lot of info in this forum, but I can’t seem to find the answers I need, so I posted this thread to help me get my truck running the best it possibly can!

So which upgrades should I do first!!!

Thanks in advance,
Brian

Brian,

Congradulations on joining the diesel fraturnity. First of all don't always believe what you read about LLY's or any other diesel engine on the net. Like someone else already mentioned, you hear more about the bad stuff than the good stiff. Getting your LLY breathing better is probably the best investment you can make. The mp and a good free flowing intake and exhaust system will make your truck run much better. Adding a programer can also show benefits in power and mpg. You also need to remeber that diesels operate in a different rpm power band than a gas engine, and it does take a little getting used to at first. I've towed a simular load as you described with my LLY and it performed flawlessly and even managed 16 mpg on level highway. Hope all this information helps. Good luck with your new truck!

Mark

**Killerbee** · 10-26-2009, 09:44 AM

Four articles imbedded in the link above.

BigBlueGMC · 10-26-2009, 10:04 AM

Yeah, I read them all.
This is my plan for starters:
LBZ mouthpiece
EGR blockoff - where can I find this?????????????
TCAI

If you or anyone else can recommend any other inexpensive mods that I don't have listed above then please let me know about them.

Thanks again for all the replies and help! You guys are great!!