Took my 3500 in yesterday to have the tsb done for poor fuel mileage, white smoke, ect. From my understanding you were suppose to get a 1.5 mpg increase on average. I picked my truck up from the dealer and took it for a spin, my mileage jumped from 11.8 around town to 16 mpg. On the interstate it will jump up to around 19-20 mpg. Can this happen from just a computer program glitch ???? It sounds like to me they may have changed out some injectors or something to increase the mileage like that. The truck does run a lot better and has more power now also. I can really tell a big difference in the performance, it would be nice if the mileage reading is really an accurate calculation. Has anyone else had this experience ???
By the way, the truck has around 6100 miles on it.


Matt

3500 4x4 quadcab dually 04.5

 

matt,

i had mine done back in oct. i noticed the same things that you noticed. mileage did increase about 1.5 hand calculated. it still isn't great and sure isn't as good as my 03 was getting. but i didn't buy the truck for the mileage. i still average about 15-16 with 50/50 driving. not bad for an 8500 lb truck.

do a search on mileage and the reflash. there are many threads on this subject.

britt

 

any louder after the flash?

 

not that i can tell. seems to run a little smoother and has better throttle response.

britt

 

Originally my overhead was off by about 1-2mpg before the TSB.
The reason you are seeing a spike from 11.8mpg to 16mpg is that first off, the overhead was displaying less mpg than actual. The next is it actually improved. If you hand calculated before, my guess is that you were actually getting about 13mpg or better. Also part of it could be driving habits (possibly). I actually tried to get better milage after the TSB and am now seeing about 16-18mpg in combo (city/highway) driving vs the 14mpg pre-TSB.

Cool?

 

I would like to know how come you all get better fuel milage?
I had mine done ,I can't tell that big of difference, filled it up yesterday 13.5 what gives? I have even tried to baby it and still does not get much better.Sorry if I seem a little

 

your mad?? couldn't tell

i was getting around 13 mpg before the reflash but now it averages around 15-16 mpg hand figured. couldn't tell you what to change. i don't really baby mine around. if i do it gets around 18-19 hwy on the overhead display.

britt

 

Be very careful with the computer mileage calculations. I had the reflash done 2 weeks ago and immediately noticed that the computer went from being 0.2 mpg off to being around 4 mpg higher than hand-calculated--this after a reflash that was supposed to fix the computer!! I am running 5 tanks through it, then will compare the mileage on the 5 tanks before and after the reflash. My driving isn't consistent enough to tell after just one tank. Don't believe 'em when they tell you computers never lie!

 

I had the reflash done a couple of weeks ago, not a very significant difference. I was getting anywhere from 11 - 13 mpg in town, now I'm getting 14 - 15mpg. I haven't noticed much of a difference as far as noise and drivability.

 

I haven't done the flash yet and just turned 10,000 miles yesterday. My last several tanks have averaged about 17.4 to 17.7 with a mix of city/highway. I use the truck as a daily driver and drive between 14 and 15 miles each way to work. The speed limit varies from 25 to 55, and I will run anywhere from 15 to 60. I start in one small town and have to pass through 2 others with 35 mph speed limits. It seems most of the decline in my mileage will come just idling at stop lights and of course on the take off from the light. When I first bought the truck I drove it almost 350 miles to get it home and got about 16.5 mpg.

I have found that if I reset the overhead often it seems to report a bit closer to the actual mileage I am getting and it is within about .2 mpg when I do this. I have also been seeing higher numbers on the overhead more often than I used to. I weighed the truck Wednesday morning and it weighed in at 8000 lbs with me sitting in the cab. I am not too disappointed with the mileage but like anyone else I would like to see it improve.

 

i filled up last monday morning, i got 15.3 mpg's [us gallons] and 90%-99% of my driving is stop/go city... i'd like to see the claimed 16-17mpg in the city some are getting......

 

how do you know if your truck needs the reflash. I have a 04 4.5 3500 DW that I bought last MAy.

 

disregard my prior post. A little digging around on DTR and I found 3 TSBs that are applicable to my 04 CTD

 

I had my TSB flash done a couple of months ago. My overhead and hand calc are fairly close--sometimes a little high, sometimes a little low, but usually within 1mpg. Currently with 200 miles on my trip odometer, my overhead is reading 17.2. All of my driving has been to and around town (two miles away) and one 80 mile round trip up and down the mountain hauling two snowmobiles. My best on a hand calc 380 miles was 19.2--and that is with winter fuel. The reflash seemed to do as advertized. I drive gently trying to maximize my fuel economy. No jackrabbit starts and keeping my engine under 2000 rpm.