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Chevy Silverado and GMC Sierra Duramax Fuel Mileage

620 messages,  Last post on Dec 15, 2012 at 3:45 PM

You are in the Chevrolet Silverado & GMC Sierra Forum.

What is this discussion about? Chevrolet Silverado 2500HD, Chevrolet Silverado 3500, GMC Sierra 2500HD, GMC Sierra 3500, Diesel, Fuel Efficiency (MPG), Truck

Messages Page 59 of 63

#573 of 620 Re: DURAMAX FUEL MILEAGE [keygmc] by hillsdale56

Jan 21, 2011 (11:43 am)

Replying to: keygmc (Jan 20, 2011 2:11 am)
Glad to read about your good results. Right now I have a half a ton of wood in the back of my ride. With all the snow we are getting here in new york, I'll. Never get stuck. But its killing my city fuel economy. Stay warm

#574 of 620 Re: DURAMAX FUEL MILEAGE [keygmc] by fueledup

Jan 27, 2011 (3:33 pm)

Replying to: keygmc (Jan 20, 2011 2:11 am)
I'm real interested in the results you experienced with the H&S tuner. I to have a 2008 2500 duramax that averages around 14 mpg. Which exact set up did you purchase ? Whats involved with the installation? How many miles have you driven with the new tuner? Are you precise with your mileage estimates? What are you getting city and highway? Thanks for your response.

#575 of 620 $4.00 diesel fuel by kacansas06

Feb 10, 2011 (1:32 pm)

With this price just over the horizon again, like back in '08, I know that I can drive my '06 Duramax diesel for much better than the 18 mpg I have been accepting for quite awhile. All I have to do is slow down my acceleration after 30 mph and drive at 55 mph as much as I can. People have short memories but I can say that back in '06 to late '08 drivers of all kinds of vehicles did slow down and did save money. I would expect that driving 15 mph slower will result in a mileage increase of 6 to 7 mpg highway and 5 to 7 mpg city. This is all based on my '06 Duramax results over the last 5 years. I have always tried to drive for better mileage since fuel has rarely been below $3.00/ gallon since I have owned the truck.

#576 of 620 Re: DURAMAX FUEL MILEAGE [fueledup] by hillsdale56

Feb 23, 2011 (7:04 am)

Replying to: fueledup (Jan 27, 2011 3:33 pm)
Hi, sorry it has taken me so long to get back to you. We are all feeling the pain at the pump. The mideast is in flames and oil has gone over 100 dollars a barrel. Know the name denise rich ? One of bill clintons inner circle. Her x husband marc rich is the one who put crude oil on the comodities market. The real reason I wanted to answer you is this. Remember my last post I said the wood I was driving around with for almost a month was killing my fuel economy?. Wasn't the wood. It was number 1 diesel. With this winter we have had. They have put a lot of kerosene in the fuel. When it hits 5 bucks a gallon, buy that time we will switch back too 2d . It was 8 degrees in upstate ny, last Sunday morning. What a winter!

#577 of 620 d-max fuel mileage by barrail

Feb 23, 2011 (7:33 am)

The tip about getting the engine to run at 180 degrees made a little difference in the trucks mileage. If nothing else, the cab warmed up sooner. Bottom line, if you want better mileage, stay off the throttle. I presently have the easy tuner set at 80 e. at the engine responce is very noticible. Fun to drive. Doing more highway driving now, but the mileage still is not 20 mph. stay tuned and thanks for all your input.

#578 of 620 Bad Mileage, Bad Power Towing... Dealer Diesel Mechanic won't help by c_coggins

Feb 28, 2011 (7:16 am)

Interesting reading...
 
Our '07 2500 Classic is great but for the mileage... avg. 13 mostly hwy and between 9-11 towing a tiny little 2 horse bumper pull with 2 ponies! Grrr. It's got 55K miles and has been well maintained.
 
My old '03 Duramax got 21 hwy 17 city... and towing got around 16 pulling a bigger trailer with bigger horses. I was hoping to get the same or better.
 
When I did the research before I bought this truck, all said the mileage was similar to the '03... now I see these threads and wonder what's going on?
 
 Is anyone out there getting good mileage at all? If so, enlighten us!

#579 of 620 Help my milage by rgferri

Mar 02, 2011 (8:47 pm)

I have a 2006 2500hd crew cab with a 3.73. i was wondering if anyone has some advice for better milage. right now im getting about 11 in the city. was driving a 2004 sierra 2500 and getting 17.5 in city. both truck are bone stock. any pointers?? thanks!!!!

#580 of 620 Re: Help my milage [rgferri] by kacansas06

Mar 03, 2011 (1:07 am)

Replying to: rgferri (Mar 02, 2011 8:47 pm)
first question: is it a diesel??? If not that is about the best you are going to get. Crew cabs weigh a lot more. If it is a diesel then I recommend you decide if you like the acceleration more than mileage. Take it easy on the diesel and you will get better mileage. If that doesn't work then the next easy step is disconnect the batteries, causing a transmission computer reset and then drive it easy. The Allison tranny behind the Duramax is a learning computer for shift points and the more hard acceleration the less up shift and fuel savings. Also the faster you drive the less fuel savings from the engine computer and tranny computer. An '06 diesel is the best one GM has produced lately for mileage.

#581 of 620 Re: Help my milage [kacansas06] by rgferri

Mar 04, 2011 (10:12 am)

Replying to: kacansas06 (Mar 03, 2011 1:07 am)
thanks for the advice. Yes it is a diesel. I just purchased it used and the computer said 10mpg and after a few days of driving i brought it up to 11.1 mpg. i have only been driving it for about 3 days now. i am hoping it keeps going up from there. I guess i was expecting mileage like my fathers 2004 duramax. is it taking me longer to raise the mpg because it has been at 10mpg for so long. would re-setting the computer on the instrument panel give me a more accurate reading??? any aftermarket products you guys suggest??? the truck has 104,800 miles on it so i am not worried about the warranty.

#582 of 620 Re: Help my milage [rgferri] by kacansas06

Mar 04, 2011 (1:26 pm)

Replying to: rgferri (Mar 04, 2011 10:12 am)
Oh yeah, reset that stupid display. The DIC that you are getting your MPG stat from arrives at it's calculation from the float position in the tank and the throttle position which means your pedal position as you drive. It is horribly inaccurate and the longer you leave it the farther off it will be. Mine say 14.4 mpg right now because I haven't changed it all winter. Winter is when a diesel gets the worst mileage for a diesel engine is most efficient when the engine is hot. I do not know where you live but here in MN I not only have the "Winter Front" covers on the grill and bumper, I added cardboard from the radiator down in front of the tranny radiator plus I covered the 2 holes left open on the bumper for the tow hooks with cardboard. This winter has been really cold but my drivetrain temps have been good thanks to the block heater and all the covers. No tendency to overheat either even on the few days that have been in the upper 40's or 50. So my calculated mileage at the pump has been 17 to 19 this winter. Close to the lowest I have seen in 50,000+ miles. Spring through fall I get 20 to 22 city(with No load) and when I tow our 16,000 lbs of boat we get 13 to 15. It really matters how you handle the drivetrain. I moderately accelerate to 35 mpg then back off and let it shift to 4th and if needed keep accelerating easy to highway speed. Maximum economical speed is 65 to 67 mph depending on head wind. I can hear the engine start to work harder in 6th with the torque converter locked up somewhere around that speed. It is the complete lack of aerodynamics of the truck which is like shoving a large stack of bricks through the air. But the dash MPG estimate is always off by 3 to 5 mpg or more for me since I have a steep driveway that it has to climb. Also you do not need to idle the truck when you stop to keep it warm for it has a huge amount of fluids that stay warm quite awhile. If you need more advice feel free to let me know if you need my email addy. Oh and if you wish to "chip" your truck get a tuner that connects in the wire connectors under the hood. The ones that plug in inside are DANgerous. For mileage without a load the lower program settings add air to the engine with the higher power setting adding fuel and air. High power settings are for people who need or wish to show off the diesel power but they can easily damage a transmission. The Allison is the "weak" point in the drivetrain but it can handle as much as 15% more power if it is in good condition. To check that have the fluid changed for the external filter has a magnet in it to detect how well it is operating.

Messages Page 59 of 63

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