Maximizing LLY fuel mileage

[gary_lucas]

I just got a new (to me) 2004.5 Sierra 2500 Diesel.

Truck has 181,000k on it.

We took it for the first trip with the camper on the highway this past weekend.

It looks like I was averaging 15.6 to 16.4 l/100k (15.08 / 14.34 MPG)

Looking at instant fuel economy I could see it was hitting as low as 9l /100k on flat stretches at constant speed. Our trip was only about 70k on the highway at constant speeds, so I expect to see better results when we go to Tacoma (300ish K)

Mileage in town is more like about 17-18l / 100k (13MPG)

It's BC so it's not flat, but it wasn't terribly hilly either, we were towing our TT (3000lbs current weight).

I was not driving as efficiently as I could, we're going to Tacoma in 2 weeks, I think that will be a better test (flatter) and I'll try to keep the lead out of my foot... And the drive is quite a bit longer... So I'll get a better sample...

My truck came with an Edge CTS in it, but it looks like the firmware hasn't been updated for awhile. It's missing the mileage calculator / mileage coach that should be there in theory.

I'm going to bring it upstairs and see if I can get it updated this weekend. I've only used it at level one, which theoretically is a mileage setting.

Any suggestions? Looks like someone already updated the mufflers, there is two giant tailpipes, I'm pretty sure that's not stock.

Thanks all

[AKMark]

I picked up an 05 2500HD CC LB 4x4 this summer. It was used on the north slope oil field of Alaska and has been prepped for extreme weather. The bumpers on it must weigh about 300 lbs a piece. It only has 91K miles on it, it does have over 12000 hours thanks to excessive idling trying to keep the occupants alive when temps dropped below -60.

Love it, TONS of power and does everything I ask of it and more. I had almost 3000lbs in the bed a few weeks ago and the rear suspension wasn't sagging, it was even with the front, but not sagging. The traction like that was amazing.

Pulling a Dead 6.0L Powerstroke she out accelerates my 6.5 empty.

I have a 13-15 mile commute everyday depending on which entry point to the Army base I have to use. I averaged 15-16 doing this run every day this summer. It dropped a little when I was pulling, but not much.

I haven't had a chance to take her on a longer drive to see what it does when it runs a full tank of fuel without having to warm the engine up multiple times. With it being -30 now and running it a little more than normal mileage is still 14, which is better than the old 6.5 did.

The 6.5 Burb got 14 in the summer doing the same run and about 12 in the winter. On the Hwy the Burb pulls close around 18-19 empty and about 13 pulling a K-5 on 1 tons and 36's.

Would love to find a way to get into the 20's, but my 235/85's probably aren't helping. I'll live with the lower mpg's to run these tires. Oh and I hand Calculate my mileage from a Garmin GPS, as both the Burb and Truck's speedo's are slightly off thanks to the tires.

[Kennedy]

The 235's actually should help. Decent height and narrow. The heavy bumpers certainly do not help, but I'm sure they'll come in handy if wildlife is standing in the road.

[AKMark]

Wildlife or the occasional vehicle that decides to cross my path....