04.5 flash to improve fuel economy available today

[PKitchen]

klenger, what was your MPG before the flash on a similar highway trip?

 

[swexlin]

So there is no loss of power (perceived or real) from this flash? I am concerned that the flash may de-tune the engine for better fuel economy.

 

[klenger]

I don't have my records with me, but when I took delivery of the truck in Denver in January, I think I got around 16. 5 MPG driving it back to Tucson. That trip was with a brand new truck, and I drove in around 65-68 MPH most of the way. Most of my driving is local commuting to work and towing the 5er, so I don't get too many opportunities to drive extended distances empty.



See https://www.turbodieselregister.com/forums/showthread.php?t=92368 for my report on my trip home with the new truck in January. Tanks 2 and 3 show the fuel used on the trip.



2) 476 miles, Computer 15. 6 MPG, Actual 17. 64



3) 446 miles, Computer 14. 6 MPG, Actual 15. 88

 

[knewman]

happy days happy days

got my truck reflashed monday morning and looks to have improved fuel mil. 1 or 2 per gal and truck runs better no pinging and falling on its face from dead start is gone. also had top secert thing done to my truck i will start a new thread for that as it doesn't relate to this at all.



Oo. :-laf Oo. :-laf Oo. :-laf

 

[SSchang]

If you're getting decent mileage, don't get the flash. I had the flash (TSB 18-037-04 ) done on Tuesday. Traveled through two tanks, 95% highway with my camper in the truck. Here's the results:



Before flash:

Computer 12. 1

Hand calc 12. 6



After flash tank 1

Computer 13. 3

Hand calc 12. 2



After flash tank 2

Computer 13. 0

Hand calc 11. 8



The computer is less accurate, and I lost . 5 MPG. The computer shows better MPG, but actually getting less. Dealer told me he can't reload the old program.

 

[Sarge]

I had the flash and went on a very short RV trip of 114 miles total. I checked it when I got back and it appears to have increased about . 5 MPG towing. No empty driving yet, so that test will have to wait.

 

[thames1948]

I am hours away from getting the new flash and am still on the fence about this because you can't go back if its worse like mentioned in a post above. My question is, because there is a cut off date on the flash, does that mean that every truck after that comes with it from factory now?

 

[phicks]

Happy Camper

I have been one of the biggest complainers of the crappy mileage these buggies are getting. However, I can report that I did have the reflash done last week and after running up and down the road all weekend my mileage has increased from 12. 0 mpg to 15. 9 mpg. Am I pleased... yes, the flash worked for me, will it work for you... probably. I will be testing mileage pulling 5th wheel this weekend over Donner, and will report my findings here.

Good Job DCX. Oo.

 

[PJ]

I got the flash and pulled my 30' travel trailer to the coast this weekend and got 11. 4 mpg. Trailer weighs about 8k. Not sure if the flash did any good. i will be going to California this weekend and driving about 600 miles. ill know more then. All I can say is my 04 305-555 got 21mpg on the very first tank.

If it didnt improve, oh well, i like this truck sooo muce better. Lots more options and it is a 3500

 

[Camp]

I just got back from a trip just a few miles short of 2000 miles. I had this flash done the day before I left. I was pulling about 8K behind the truck. I didn't see any real improvement in economy. I averaged about 11. 5 mpg at 70 mph from Denver to Beatty, NV. The flash did help the ruff start an white smoke issue at cooler temps though. As a note, I also was running an Edge EZ on setting 2 for the whole trip.



I'm really having trouble with the fact that I sold a Duramax that would get 15 mpg on the same trip at the same speed and pull the passes faster

 

[claymike]

I called the dealer to schedule the flash and was asked where did you get that information. It was like I stole something, I told them DC, I was then told I could bring it in but some trucks can’t be flashed??? :-{} I told the mook it’s a computer and there will be no problem. This service writer is the owners son and is not very bright. I called back today and talked to my usual rep and he said bring it in, in the morning and they will take care of it. I hope it all works out.

 

[DGStrate]

Jury is out...

I got the flash last week, but then parked the truck for a few days (bopped around in the Jeep ).

Last night, I had to make an unscheduled trip to Grand Rapids for a client.



Results

(ALL Hand calc'd, with mileage tracked via GPS due to 315's)



Going there:

167 miles / 10. 7 gallons = 15. 607 mpg

*not so good!*

BUT - there was a strong headwind and I was traveling at 74-75 mph.



Returning:

169 miles / 8. 6 gallons = 19. 651 mpg

*much better than the trip out*

NOTE: this was at 70-71 mph with some cross wind



Current outlook:

Flash did not seem to affect me much... Power seems slightly down (truck does not seem as quick to spool turbo and plant you in the seat as before). I was able to get between 18-20. 5mpg before the flash (when driving easy) so I do not think the flash had a dramatic effect either way.



The thing I _do_ notice is that the truck seems sluggish, not as free revvin' as before.



ALSO there is a pronounced rattle at even pedal cruising (almost like a spark knock on a gasser)...

Anyone know what this is? The truck did not used to do this...

Should I be checking injectors or valve clearances or anything else?



Thanks in advance for any input or thoughts!



PS - 7k miles on truck currently

 

[vagabond]

It is amazing the different results we seem to get. On mine the milage is much better. the truck is more responsive. I do seem to have a rattle now but more like the normal deisel rattle. I kind of like that but it will never sound like my 2000. Tommie

 

[claymike]

Just had mine done, have not driven far enough to check the mileage but truck seems to have a little more kick then before and alot of the pinging is gone. Will be towing 21k gross this weekend and that should tell me if it helped or not.

 

[Rhinohd]

Just made my FLASH appointment for next week. Right now I do 50/50 mix highway and city. I am getting (hand calc) 14. 5 mpg consecutively.



I am also asking they enable the high idle. The service rep had no idea what I was talking about but she said she would look into it. Is their an "official" name for enabling this?

 

[ESTELJ]

i just put the TST back on after the reflash. milage is all around town but ... . seems smoother. Could just be my optimistic mind. runs fine though if it helps ease your mind.

 

[JCotte]

KNEWMAN. . I looked for a new post and did not see that you started one. Give us a clue

 

[BlueRam2500]

I also made my flash appointment for Monday and told the dealer that they need to recalibrate my speedo for the second time. I average 12-14 around town with some highway. I told them I don't see smoke but the fuel mileage was terrible and they knew all about the computer flash. She said that they would check it out and possibly flash if necessary

 

[TTubb]

TSB 18-037-04 did not enable high idle in my truck. TT

 

[klenger]

I had mine done on Thursday, and drove from Tucson to Denver (900 miles) yesterday. Filled up just before I left, once in Las Vagas NM, and again in Denver. Average milage for the 900 miles was 18. 5 going 70-75 MPH most of the way. I am very pleased with the results.

Got back from Denver today. I drove through the mountains (I-70 to Frisco, and south highway 9 to US-285 to Sante Fe NM, then I-25 to to I-10) on the return trip home because I miss seeing real mountains with snow. Drove 60-65 MPH for 900 miles and crossed two 10,000+ foot passes. Average milage on the return trip was 20. 9 MPG I went 660 miles on the first tank of the trip (Denver to Hatch NM) Oo. Oo. Oo.



I am impressed. Truck is a 3500 SRW 6 speed 3. 73.