Fuel Economy

[Paul2500HD]

I've had my 2500HD Duramax for 5 months and on my recent fillup, I averaged 12.3 miles per gallon empty. I have also had instances when I pulled out to pass, and the engine backfired. This has happened five or six times. Any ideas or help would be greatly appreciated. I absoutely enjoy all the posts and the information provided on TDP, Happy New Year.

[GMC Hauler]

You might want to post over in the duramax forum. This forum is for the older 6.5 diesels.

Welcome to the board. :D

[rjschoolcraft]

This topic is being moved to the Duramax forum.

[rob@rone.ca]

You should be getting a lot better than that.

Just to confirm, you could try another trip or two, and fill up to the top after each, since it can vary quite a bit if the fill level in the tank isn't exactly the same each time.

If your driving is mostly short trips in cold weather that would bring it down quite a bit, seems it really guzzles til it warms up.

The "backfire" could be a "turbo bark", when you suddenly step on it?? If not, there is a probem that needs fixing.

What does your DIC show for total fuel consumed to date, and total mileage to date - does that match your calcs?

As below, I have a lot of the options that bring your economy down - ie 4x4, 3500 weight empty about 7150, and my economy is around 17.5 per US gal empty in mixed driving, and this summer with a 3000 lb camper on, I was getting 13 average.

I now have about 5500 total miles on it, and no change in economy since brand new. The DIC measurements on mine are always 1 or 2 mpg optimistic. The error seems to lie in the fuel consumed measurement, since I put more in the tank that what it says it burned.

[Black95TD]

Paul,

My most recent fill up was around 13 but this is all local trips in winter temps. Mine is a 2500 empty with a ladder rack. Same rig on the highway at 65 mph is around 18 or better depending on the wind. My mixed driving - some local and some on the highway is usually around 16 or better. All in all, I am very pleased with the mileage as its better than my old 95 6.5 AND its quieter and much more powerful.

Have not had any hesitation. I do get a fair amount of smoke when I jump on it to pass.

[Paul2500HD]

Originally posted by GMC Hauler:
You might want to post over in the duramax forum. This forum is for the older 6.5 diesels.

Welcome to the board. :D

[Paul2500HD]

Black95TD,

Thanks for the reply. I took the truck in to the dealer today and there were no codes but, they did install a newer version of software for the programmer. I'll continue to keep track and see how it goes. I have 4700 miles on the truck so far.

Thanks,
Paul

[Paul2500HD]

Originally posted by rob from bc canada:
You should be getting a lot better than that.

Just to confirm, you could try another trip or two, and fill up to the top after each, since it can vary quite a bit if the fill level in the tank isn't exactly the same each time.

If your driving is mostly short trips in cold weather that would bring it down quite a bit, seems it really guzzles til it warms up.

The "backfire" could be a "turbo bark", when you suddenly step on it?? If not, there is a probem that needs fixing.

What does your DIC show for total fuel consumed to date, and total mileage to date - does that match your calcs?

As below, I have a lot of the options that bring your economy down - ie 4x4, 3500 weight empty about 7150, and my economy is around 17.5 per US gal empty in mixed driving, and this summer with a 3000 lb camper on, I was getting 13 average.

I now have about 5500 total miles on it, and no change in economy since brand new. The DIC measurements on mine are always 1 or 2 mpg optimistic. The error seems to lie in the fuel consumed measurement, since I put more in the tank that what it says it burned. rob from bc canada,

Thanks for the reply. My truck is a 4 x 4 and so far I only have 4700 miles on it. I took it in today and there were no codes but they installed a new version of software for the programmer. I have noticed that the actual gallons going in the tank is different from what the DIC shows. The same is true for the MPG. I have tracked what the DIC shows and I have done actual calculatons. I have never hit 17.5 MPG. Going to the dealer today is all downhill basically and I reset the MPG when I left the house and 90 miles later when I got to the dealer it was at 17.2. I have checked tire pressures etc. I installed a KNN air filter which I thought would help a little but, I didn't notice any appreciable difference. I'll keep you posted.

Thanks again,
Paul2500HD