PDA

View Full Version : 06' Duramax mpg


UrbanGreen
03-04-2008, 02:54 AM
I have a 06' 2500 duramax, 4x4, allison tran. Looking thru some of the old threads I have read of some people getting anywhere from 15mpg to 22mpg pulling heavier loads than I pull with their duramax. I normally pull about 4k lbs (open trailer/ equipment) and sometimes a 14' dump trailer loaded (not quite sure on weight). My duramax doesnt even know that I have a load behind it I think because I get 10-12mpg no matter what.
I was wondering if anybody knows of what I could do to improve my mpg. I am not sure with all of hundreds of bolt-ons and chips that out there. I would like to know what others have tried and liked or disliked. Thanks

PLM-1
03-04-2008, 03:10 AM
That's pretty low. Clean air and fuel filter? Larger tires? My 04 LB7 averages 16-17 mpg mixed city/highway with a combo of towing and not riding on 265's. Don't forget we are on winter fuel so fuel mileage reflects that.

UrbanGreen
03-04-2008, 03:14 AM
when i went from factory tires to 285s i lost 2 mpg but got that back with a new intake. ikeep fuel filters and oil filters changed every 7k. I use GM filters, do you recommend something else?

PLM-1
03-04-2008, 03:18 AM
And air filter is ok? If your truck is under warranty I would take it to the dealer and explain what's going on. You may have bad injectors (which i haven't heard of on an LBZ). any white smoke?

UrbanGreen
03-04-2008, 03:21 AM
I have already had GM look at it. They did find that my emissions sensors were screwed up and the had to reprogram it. Afterwards I told them I was still getting lousy gas mileage and they told me they couldn't find anything wrong. They even rechecked the computers and said everything was ok.

UrbanGreen
03-04-2008, 03:24 AM
As far as smoke, before they did the first reprogram it was smoking. But now just a little black smoke if you really have to get on.

Lawnworks
03-04-2008, 09:03 AM
I think it is b/c most people lie about there mileage or don't actually compute it by hand. They are a flat out liar if they say they get 22mpg while pulling anything. I have an '04 Duramax and I barely get 16 pulling nothing.

GSPHUNTER
03-04-2008, 09:23 AM
I think it is b/c most people lie about there mileage or don't actually compute it by hand. They are a flat out liar if they say they get 22mpg while pulling anything. I have an '04 Duramax and I barely get 16 pulling nothing.


This is pretty much the truth. I don't know why, but it does seem like people always want to overstate their mileage for whatever reason. I've got an '01 Dmax that gets 16-18 with all kinds of driving. I've never really noticed it go below that, but if I'm real nice on the highway, I can get about 20 mpg. That is going about 60-65 mph though.

The newer diesels aren't turning out near as good of mileage as the older ones. They got into power races between the big three diesel trucks and it killed the high mpg quality of diesel pickups. My dad's 07 Classic Dmax only gets about 15 mpg.

Try some Howe's or Lucas fuel additive. This adds some lubrication to your fuel, which new diesel few lacks in. I notice some mpg change when using it, and it's supposed to be good for your fuel components. Also, it will pay for itself in fuel savings.

Good Luck.

TXNSLighting
03-04-2008, 09:34 AM
Which duramax do you have? that will make a difference. LLY or LBZ? I have an 07 LBZ and you have to make sure the fuel filter is changed pretty often and the air filter is clean. mine gets 19 hwy. alot to do with the 6 spd allison. bout 15 in town.

UrbanGreen
03-04-2008, 10:47 AM
I have the 6.6l LBZ dmax. I change the fuel filter every 7K, do I need to change it more often? When I drive on the highway the I have gotten going about 65mph was 13-14mpg. Something cant be right. Im not really expecting 22mpg but something a little better than what I am getting.

Venturewest
03-04-2008, 11:01 AM
I have an '04. At 65mph I get maybe 18 to 19. My computer says sometimes 20 but I think if I hand compute it, it will be less. That is with no load.

Mine was getting about 2 mpg less and I used a programmer on it to do a mild performance boost and it instantly got better mileage.

I have heard that the high flow air boxes and filters make an incredible differance. my brother in law just did his '05 and it helped alot.

UrbanGreen
03-04-2008, 11:06 AM
Is my 06' getting worse mpg than the older models because of the emmissions crap they had to put on them? Injecters? This cannot be right, I had a 04' HEMI that got 12mpg pulling the same equipment!

Blueribbonlawns
03-04-2008, 02:29 PM
I have a 06 duramax bone stock and i get 12 in town and 21 on the highway i have in told that i can get 5-10mpg better if i chip it and put some bigger pipes on it but i really dont want to void the warrenty.

Blueribbonlawns
03-04-2008, 05:06 PM
How can you tell wich engine you have in your duramax

PLM-1
03-04-2008, 05:16 PM
I have a 06 duramax bone stock and i get 12 in town and 21 on the highway i have in told that i can get 5-10mpg better if i chip it and put some bigger pipes on it but i really dont want to void the warrenty.

5-10 LOLOLOL I wish!! Seriously though, I picked up MAYBE 2mpg with Edge Juice with Attitude.

LB7 Duramax 01-04.5 -->No emissions components except Cali
LLY Duramax 04.5-05 -->Variable vane turbo and emissions crap
LBZ Duramax 06-07.5 -->Very near the same as LLY except more emissions
LMM Duramax 07.5+-->Similar to LLY/LBZ except with DPF

JShe8918
03-04-2008, 05:48 PM
my 05 LLY gets about 17 MPG and towing my equipment i get roughly 14 mpg...

TXNSLighting
03-04-2008, 06:25 PM
Is my 06' getting worse mpg than the older models because of the emmissions crap they had to put on them? Injecters? This cannot be right, I had a 04' HEMI that got 12mpg pulling the same equipment!

you dont have emmision crap on yours.

TXNSLighting
03-04-2008, 06:26 PM
How can you tell wich engine you have in your duramax

if its an lbz the duramax plate say allison transmission duramax. the others just say duramax diesel. lly lb7 doesnt make a difference.

OhioMowerGuy
03-04-2008, 06:57 PM
I think hes talking about the cat and egr valve.

UrbanGreen
03-04-2008, 07:28 PM
I think hes talking about the cat and egr valve.

This might be it. When I took it in for the first time about the mpg they told that part of the emmissions wasnt right. Thats not the exact wording (I cant remember exactly what he said). They reprogrammed it and said they could find nothing else. This is my first diesel and am still learning about them and do not know anything about the emmissions parts. If you guys have any suggestions I would greatly appreciate it.

GSPHUNTER
03-04-2008, 07:41 PM
You might try ditching your cat and muffler. This will let it breathe a little better than stock. My '01 has not cat from the factory.

UrbanGreen
03-04-2008, 07:52 PM
I dont want to void the warrenty. My dealership told me that I could do chips and bolt-ons and they pretty much look the other way. I dont know if they would go for that.

UrbanGreen
03-04-2008, 07:57 PM
[QUOTE=PLM-1;2188272] You may have bad injectors (which i haven't heard of on an LBZ).

Are there any signs that might indicate its injectors?:confused:

PLM-1
03-05-2008, 12:28 AM
[QUOTE=PLM-1;2188272] You may have bad injectors (which i haven't heard of on an LBZ).

Are there any signs that might indicate its injectors?:confused:


That's why I asked about white smoke. Was your EGR sticking?..is that what was wrong with your "emissions"?

TXNSLighting
03-05-2008, 09:44 AM
I think hes talking about the cat and egr valve.

the cats have been on every duramax. and egr...its not a requirement. so yeh.

Blueribbonlawns
03-05-2008, 01:14 PM
I wish i could straight pipe mine so bad they sound so cool im going to call my dealership today and see what they say.
But if i do straight pipe it do you think it will get better fuel milege??

UrbanGreen
03-05-2008, 02:15 PM
[QUOTE=UrbanGreen;2189607]


That's why I asked about white smoke. Was your EGR sticking?..is that what was wrong with your "emissions"?

I found my service ticket from when I took it in. Valve/Gasket and EGR was replaced. It was reprogrammed as well as powertrain control module for the transmission. I took it in because there was white smoke. After they serviced it no more smoke but still poor mpg. I took back they said they found nother else wrong.:confused:

dane1985
03-05-2008, 02:18 PM
I have an 06 lbz and the only thing I have done to it is put a cat-back exhaust on. It has helped somewhat just getting rid of the huge stock muffler. The biggest thing is the air filter and fuel filter changes on a regular basis.

dane1985
03-05-2008, 02:21 PM
Also if you take out your cat on a lbz your check engine light will most likely come on and cause you to possibly go into limp mode. The lbz engines are very picky. I ran mine with the cat still on but with no muffler and mine went into limp mode until I put a full cat-back system on it.

PLM-1
03-05-2008, 02:38 PM
There is something you can put on them to take care of the light. You really need to check out dieselplace.com It is dedicated to these trucks and have all the answers.

dane1985
03-05-2008, 02:44 PM
Ya you can get a finger stick and egr blocker plate to take of it.

PLM-1
03-05-2008, 02:51 PM
Ya you can get a finger stick and egr blocker plate to take of it.

Finger stick ... that's the name i was looking for, it just wasn't coming to me.

OhioMowerGuy
03-05-2008, 03:35 PM
Theres no cat or egr valve on my 04 lb7

UrbanGreen
03-05-2008, 05:18 PM
dane1985 what kind of mpg you getting before and after the new exhaust? How much do pull with yours?

dane1985
03-06-2008, 02:17 PM
Im not really sure what I was getting before I changed the exhaust. I mainly changed it just to let the engine breathe a little more. I pull everyday during the lawncare season with that truck. I had a 95 chevy with a 6.5 diesel that was great on fuel but I sold it for an 03 with the 6.0L gasser.

PLM-1
03-06-2008, 02:29 PM
Theres no cat or egr valve on my 04 lb7

Only Cali emissions has a cat and EGR. Federal emissions do not on an LB7.