...Well, just went throught the first tank where the focus was fuel milage (for the most part http://www.dieselplace.com/forum/smileys/smiley36.gif) and the DIC read 18.5 mpg and hand calculations was 18.2 mpg. 1500 miles on the truck now and I am impressed! http://www.dieselplace.com/forum/smileys/smiley32.gif The DIC was reading 19.3 earlier in the week, but ran into a few WOT moments, well you all know how it goes. The only problem with this LLY is jealous power stroke friends. I have heard it all from one of the guys. Stuff like how I am not going to get 18 mpg right out of the box and when I told him that my DIC was reading upper 18's, he said that those DIC's were always 4 mpg off. http://www.dieselplace.com/forum/smileys/smiley5.gif Oh well, the proof is in the pudding I guess. Truck is cool!


On edit: We are wondering what the differences is between 3500 mpg's and 2500hd mpg's. If you wouldn't mind posting what you get. This may have been beaten into the ground already, but what else do we have to do? Thanks!Edited by: Reineke

A check of mine showed the DIC to be about .2 mpg less than the hand calculation. Got 17.9 mpg on cross country running between 70 and 75 mph with approx 2500 lb load. Just clocked off 19 mpg in several trips thru town and some slow (55 mph) travel in S. Georgia. Pretty pleased compared to the 8.1 gasser I had that would only get 11 mpg on same type travel and max of 13 mpg downhill with a tail wind or straight off a cliff.

What trucks do y'all have? 2500? 3500? gears?auto? I know forsure I wish I had some of good mpg y'all are getting.. I got a 2004.5 and I am no way get that..I got a 3500 Cab & Chassie, The best i got is 10 on the first tank and now it's getting 5.. I try it at 45 to 55 mph and 60 to 75 mph.. It's better at 45 to 55.. I am going to try it wot on a tank and c if it will get 2..Dealer has look at it and refash it..still the same..Good luck on the good Mpg..I'm glad someone getting it..


I have done started http://www.dieselplace.com/forum/smileys/smiley19.gifhttp://www.dieselplace.com/forum/smileys/smiley19.gifhttp://www.dieselplace.com/forum/smileys/smiley19.gifhttp://www.dieselplace.com/forum/smileys/smiley19.gif But it was time too.





Ps I put around 80,000 mile on my truck a year.. Now you know why I am http://www.dieselplace.com/forum/smileys/smiley19.gifhttp://www.dieselplace.com/forum/smileys/smiley19.gifEdited by: willivy

I now have about 1800 miles on my 05 and I get 16-17mpg running 75-80
on the highway juice in level 1. Pulled ~ 7000lbs over 3 Colorado
passes and got between 12.5 and 13 mpg running 75-80 juice in level
2. I didnt see any significant changes to the gas mileage w/ or
w/o the juice but haven't really been able to keep my foot out of it
long enough to see what she's really capable of getting. My DIC
has always been within 1-2% of my hand calculations.



D.

Willivy


GM buy back time!http://www.dieselplace.com/forum/smileys/smiley7.gif

Willivy,


2500HD CC D/A 3.73:1 gears. Milage got through no additional weight and driving like an old man. Good luck to you and your milage. You definately need to be getting the best with 80k/year milage.

http://www.dieselplace.com/forum/smileys/smiley1.gif 2500HD, 2004, GMC That's completely stock. Got 16.5 mpg for the first 1500 miles. After the fisrt 1500 mile mileage went up to 18.8 mpg and has stayed there. Now have 7500 miles and still 18.8 mpg. This is 75% highway, 25% city and no towing. It's stock with no Juice and it will stay that way. Why try and change a good thing I think.

I drive about 75% highway and 25% streets. If I hold it to 65mph
avg on highway with little or no hard acceleration I get 20mpg hand
calculated (22.4mpg DIC). When I just go with traffic (avg. 75mph
with more hard accelerations) I get 16.5mpg hand calculated (DIC says
18.4mpg). I haven't figured out why my DIC is always about 2mpg
off. This is better mileage than my 2000 5.3L 1/2ton
Silverado piston slapper got.

I just left my Dealer.. He talk to GM and they said it was a 3500 truck.. They told them that if it was a 2500 truck it will get better.. Sound to me like alot of B/S....

That does sound like BS, part of the tonners bed is composite, so it should help lighten the bed (theoretically thinking....http://www.dieselplace.com/forum/smileys/smiley2.gif) I could possibly think that it would be 1 maybe 2 mpg's lower, but the numbers you are reporting do not sound right. Maybe we can get more 3500's to post their milage for reference purposes...

Willivy, Mine is a 2500 04.5 with 3.73 crew cab long box and 100 per cent stock. Don't think there should be any difference in fuel consumption between the 2500 and 3500 unless each was loaded to max weight wise. Same truck except for springing as far as I know.

WEll I tow the same load on the same hwy. Buy fuel at the same place.This truck is way off from my Ford got 13 mph,Dodge got 14 mpg,Chevy getting 4 to 5 more 4 that 5mpg.. It did it for the dealer and me..tank #1- 23mpg no load,#2- 10.2mpg,#3 -4.8mpg.,,,#5-5.1mpg,,#6 3.8mpg..#7-5.7mpg and I can keep going on and it don't get better..There no leaks no where.. I had a 3/4 ford with a 351 ,auto overdrive,355 gear with 245,600 miles on it doing the same thing and it got 8.4mpg..

3500 w/ZF6 ext cab = 18-20 mpg. Avg mpg 18.3 for 16K miles. 2500 w/ZF6 crew cab = 23-25 mpg. Avg mpg 23.7 for 17K miles. Neither loaded or pulled with. Hand calculated. DIC is 0.2 mpg lower. Service advisor "hinted" the 3500s are set up to protect the vehicle when they are heavily used. GM says there is more resistance for the 3500s.

First 500 miles from the dealer to my front door, 15.2 mpg according to the DIC. Speed varied between 50-75 mph.



Juice on level 0.

3.73:1 gears.



'05 LLY GMC 3500 Crew LB 4x4, Juice w/ Attitude, AFE intake, Dynomax 4" Stainless exhaust

3500's weigh aprox. 750 pounds more. My 3500 2wd LLY will get 18 under perfect conditions. The mileage got better after the reflash and after about 60,000 miles. My 3500 4wd LLY's best is only 16. No help with reflash and it only has about 35,000 miles so far. My 2001 2500 4wd would get 22 driving it easy and my 2003 3500 4wd cc will get 19 under perfect conditions. My LB7's get about 10-20% better fuel mileage straight across the board!

I have a 2500 Ex Cab 4X4 with juice on #1 I get 18.3 mpg on the highway. My DIC says 17.2.

04 LB7,3500 juice set at level 3 always. 17.5 mpg mostly highway.

well today I tow my Tractor and bushog. Got there and weight it on there scales..Truck,tractor,trailer and me.. Total weight was 25,640


Then unhook trailer and tractor...Weight just the truck and me. It weight 7500.. It was loaded too..I was towing 18,140.. The mpg on this trip was the same as one with a light load let's say 6000.


Edited by: willivy

2500hd crew cab auto. only have 310 miles so the first tank i only got 16.2. second tank so far avg is about 17.4

05 2500 crew cab long bed duramax 4x4 3.73's only have 550 miles so far. just got gas tonight. 17.9 on first tank.





03 8.1 dually crew cab 2wd. 4.10's 39,000 miles. 12.4 average hand calculated . sometimes empty sometimes towing up to 10k at interstate speeds. never had worse than 10.8. best was 14.8

Just pulled a long haul trip across USA, from Idaho Falls, ID to Atlantic City, NJ. 04.5 crew-cab dually 4x4 auto. Towing car trailer with 67 Coronet 440, av'gd 65mph mileage 13mpg. Coming back with empty trailer, av'gd 71mph mileage 13.5mpg.http://www.dieselplace.com/forum/smileys/smiley19.gif Truck has 15K now, dealer kept telling would be better by now, but no such luckhttp://www.dieselplace.com/forum/smileys/smiley7.gif Running empty 70-75mph the best i can get is 15.5 mpg if i slow down to 65 mph might get 16mpg. Im not a happy camper, but i see some of you have it worse. Whole trip was 5,000 miles and about 400 gallons of fuel.Edited by: supermex

I WISH MY TRUCK GOT 13 OR 13.5 MPG..

2005 GMC CC D/A, 2WD. 50/50 highway/stop-n-go commuting so far. No
performance mods, adding 5% for LT275/70R17 tires since they were
installed. DIC usually shows about 10% better economy than actual. I've
been adding the Primrose fuel conditioner from about tank #4 on. I ahve
not pulled anything with it as of yet.



Tank 1: 15.1 MPG

Tank 2: 14.3

Tank 3: 14.3

Tank 4: 14.6

Tank 5: 14.5

Tank 6: 14.6

Tank 7: 14.6

Tank 8: 14.3

Tank 9: 13.9

Tank 10: 14.1

Tank 11: 15.3 (Cooler weather, not as much A/C usage)

Tank 12: 15.3



I'm not real pleased with the economy, but then again my '02 1500HD
6.0/4L80E 4.10 2WD usually returned 11.5 to 12.0 MPG under the same
conditions, and this truck is prolly 700 pounds heavier! The REAL
payoff will be when I'm pulling one of my Pontiacs!

05 2500 HD D/A CC LB 4x4 SRW, 3500 miles on it. Mileage stays at 12.5 to 13.4 no matter how it is driven. No long trips (15+ hour drives) yet, but several 100 mile at 65. 13.2 mpg. I'll bet the sob even gets 13.5 while going down the highway on the back of a carrier at 0 rpm. Engine keeps getting louder (engine, not exhaust). No where near the truck the 02 was. Am seriously beginning thinking of dumping it and buying a very low mileage 02 for a premium price.

Supermex,
My average mileage since I bought the truck in March '04 is just under 15 MPG - this includes towing.

I get between 10 and 13 MPG when I'm towing, depending on what I tow and how fast I tow it. I get between 16 and 18 MPG on my city commute to & from work, and I can get as much as 19-20 MPG if I'm cruising on the freeway.

I have noticed that towing anything at engine RPMs at or above 2,100 will significantly lower mileage. If I keep the engine turning at 1,900 - 2,000 RPM, then mileage is about optimal.

I see by your sig that you have a dually. This will lower mileage a bit since you are pushing more air, which has exponentially greater effect at higher speeds.

Recently returned from a trip to Georgia from Central Florida. apx 1100 miles 04LLY CC/SB. Averaged 73 mph up with the egr disconnected, no load, and got 19.5 hand calculated, 20.2 on the dic.


On the return trip with the egr connected and apx 73 mph hand calculated 20.5 mpg.


No mods except homemade cold air. 9000 miles on the speedo.


Jeff

I have a 3500 04.5 crew cab long box ... 100 per cent stock. City
mileage is 15 to 16 mpg. On the highway (if I am easy on the pedal) I
get 20 to 22 mpg. Range on the DIC (if I fill up right after a good
mileage highway drive) for a full tank is 560 miles.

willivy, your truck be sick dude! http://www.dieselplace.com/forum/smileys/smiley19.gif You are not likely to get the problem fixed at most dealerships, unfortunately they are not well versed on the LLY's. You might try posting on the "Ask the Techs" forum and get some ideas from them to take to the stealership. I do this anytime I take the Dumax in for service.


I haven't checked mpg's in a while, last time highway was about 18-19 at 70mph, around town 14-15. Like many others there is a direct correlation between my mpg's and my ability to keep my foot out of the accelerator. Dang trucks are too much fun to throttle! http://www.dieselplace.com/forum/smileys/hihi.gif


Towing my 5ver with a GCW of 24-25k I average about 8 mpg's, respectable for that much weight IMHO. Of course I usually pull at 65-70mph, slowing down should improve mpg's one would think. JJ http://www.dieselplace.com/forum/smileys/smiley4.gif

JJ- you have almost the same combo as I will have, Just ordered 05 3500 C/C D/A Dooley, My toy hauler is 18k 41' and 12'8 tall. When I tow with my 01 2500HD D/A juiced and running hard I get 8.5-9.5 if I go anything over 68-70 mph if I stay under 65 ish I can pull 9-10 and under 60 nI can pull 10.5-11 with a best of 12.8 on one trip to northern WI with the quads. I hope the new truck is close I only upgraded for the crew cab, tired of the kids winehttp://www.dieselplace.com/forum/smileys/smiley7.gif. Now I pulled my 18k Gn to Indiana this past week and got 12 going with traffic 75 Ish combined empty wt of 13500 and loaded back of 18,000 that said I have noticed that when I run winter blend the mileage drops off on all of the trucks we own at least1-2 mpg. jm2c

Well i going to try and juice it up soon.Maybe it will help some.. It may fix it for good.Who knows..

SLT Dually D/A 2004.5 Ext.Cab Long bed. Get about 13.7 Around town. Noticed running engine noise getting a little louder with about 6000 Miles. Only mod for now banks 4" Cat back. EGR Plugged in due to trip soon to make to dealer for other warranty work including leaking AC just noticed.