2004.5 Mileage Improvement?

[KNorthcutt]

I have 9000 miles on my stock truck, mileage has not improved. I am getting 13 in city and 15 on the highway. What things can I do to improve the mileage without voiding my factory warranty. Options will not be considered if I have to take the product off before I visit the dealer. Any help will be appreciated.

 

[wyosteve]

Don't know that I can offer much help, but with your rig, the mileage is not that far off from most. The auto hurts a little I feel. My rig in my sig. runs 16-17 mixed town and 2 lane and about 16 @ 80mph. That is basically the same as my 01 HO did. I'd probably suggest making sure the intercooler hose bolts are tight and possibly change the fuel filter if you haven't yet.

 

[Gbrady]

I have the same truck you have and I am getting the same fuel mileage. I have to admit I do not baby it. If I keep the rmps at 1800 or less I can all most get 17. I just don't want to drive that slow. I really do like the truck. It being a 3500, 4x4, QC, with a long bed, I really did not thinkl I would getting much better. Most of the guys I know that are getting 19 and above have two wheel drive.



Best regards,

Gary

 

[txhawg]

1850 RPMS seems to be the sweet spot. I have a 2WD with auto and am averaging about 18 MPG with a mix of 60% Highway and 40% around town. I have gotten as high as 21, but that was all highway, never going above 2000 RPM. Definitely not repeatable, but it was exciting to see that number on my calculator. I hope you are hand-calcing the numbers, because my overhead averages 2. 5 MPG lower than hand calc.

 

[turboost]

I run mine fairly hard most of the time and do about 70-80mph on the highway. I have just over 2k miles on the truck and the lowest I have gotten with 70% city driving is 16mpg. If I baby it on the highway and do 60-65mph I can get 24mpg. I think 4wd and the auto hurt more than people like to think. Especially if you have both. BTW my build date is 1-2-04 if I remember right.

 

[CPittman]

Total Avg. Mileage



11. 65

12. 67

17. 88

12. 22

14. 45

15. 24

15. 15

16. 07

15. 61

16. 20

14. 42

16. 05

15. 88

13. 96

15. 45

14. 52

16. 50

16. 06

17. 04

16. 35

14. 28

15. 53

16. 61

15. 97

15. 19

14. 71

14. 95



These are some of the mileage numbers for my truck from when it was new. If I can get 15 to 16 around town and some mixed highway I think thats OK for an HD truck. Highway trips can go over 18 and up to 19 if I keep it below 2000 rpm, but with my gears thats just too slow.

 

[Cryppie]

My advice is get the heaviest trailer you can find behind it for a few hundred miles. I picked up 1. 5 mpg by pulling a 5500 lb trailer just over a 1000 miles, and another couple hundred with my 14k 5er. The sooner you can get the rings seated well, the sooner your mileage will go up... Cummins love to work.

 

[hasselbach]

I wonder if a different air box or freer flowing air filter would help? My filter gage always reads about 50%, so either the box or the paper filter is a restriction.

 

[DPelletier]

hasselbach,

Are you stock? My filter gauge never moves, but I saw a TSB on the filter minder that required replacement with a properly calibrated one (AA vs. AB revision, I believe), but I would have thought your 2004. 5 would have the new one.



Dave

 

[hasselbach]

hasselbach,

Are you stock? My filter gauge never moves, but I saw a TSB on the filter minder that required replacement with a properly calibrated one (AA vs. AB revision, I believe), but I would have thought your 2004. 5 would have the new one.



Dave

sort of, it started doing this when I gutted the air tube and inserted a 4" pipe inside of it. It didn't do this before I did the mod. I think I'll end up with AFE's box and tube anyway.

 

[txhawg]

I wonder if a different air box or freer flowing air filter would help? My filter gage always reads about 50%, so either the box or the paper filter is a restriction.

The filter minder will register the MAXIMUM air draw encountered, and will not move up from there until you press the button. If it always shows 50%, you should be OK.

 

[Piers]

I too am dissapointed with the mileage on my 04. 5, 13. 5 was my average city/hwy, i changed the cam in it last week & so far, my average has come up to 16. Still not what I would like, but it is getting better. I found that they retarded the cam timing on the 03 and newer trucks by 7 degrees. I'm going to try a few different grinds and see which works best for fuel mileage... . the fact that it runs 13. 3 @ 102. 49mph has nothing to do with the poor mileage

 

[WNowlan]

Cummins retarded the cam timing to get the emssions compliant for 2004. This has been the practise of all diesel engine manufacutres. MPG does suffer when they have to decrease particulates.



How does this help with the overall objective to have a cleaner enviroment if you have to burn more fuel to do the same job? That is a question the Government will not answer. They want cleaner air (which I also want) but to do it with todays technolgy you have to burn more fuel.



My . 02.

 

[RKerner]

cam questions

I too am dissapointed with the mileage on my 04. 5, 13. 5 was my average city/hwy, i changed the cam in it last week & so far, my average has come up to 16. Still not what I would like, but it is getting better. I found that they retarded the cam timing on the 03 and newer trucks by 7 degrees. I'm going to try a few different grinds and see which works best for fuel mileage... . the fact that it runs 13. 3 @ 102. 49mph has nothing to do with the poor mileage

Did you put one of your grinds in or just advance the timing back to pre 03 specs? Does the stock 600 cam have the same lift, duration, lobe separation and centerlines as pre 600 Common Rail engines?

 

[electraglide01]

I too have been really disappointed with the fuel mileage on my 04. 5 4x4. In fact it was what lead me to find TDR and I have been really impressed with the knowledge on the board.



I have not done any mods yet, but am getting ready to try a straight pipe and some inlet mods.



I have about 17K miles on the truck and have seen the mileage go up from about 12. 5 to 15. 7. Improved but still not quite where I want to be. Truck gets a lot of highway miles at 70-80 mph. As you can imagine, the faster I go, the more the mileage suffers.



I always hand calc. I changed the way I fuel, now topping off until I can see the fuel level in the filler neck. Takes some patience, but the results are much more consistant.



The local dealer told me that he heard that Dodge has programmed several fuel curves in the computer (Changes at 5K, 10K, and 15K miles). I don't know if this is true or not, but I did see the most substainal increase in fuel mileage at 15K miles. Anyone else heard this?



I agree working the truck seems to help. I have been running non-synthetic oil until I hit 20K and then will change over to synthetic.



One of the reasons that I have been waiting on some mods is that I want some data before and after straight piping. Has anyone looked at the backpressure between the turbo and Cat prior to straight piping it? I was thinking of having the local muffler shop weld in a fitting before the Cat so I could look at the pressure.



Mileage seems to go down pretty fast after about 2000RPM. I was also thinking of putting taller tires on (have stock 265's on now). This will increase the rolling resistance and drag (by raising the truck a little higher) but may be worth it overall. Any experience out there?



Finally, at about 7K miles, I had the dealer reflash the computer. Mileage on the trip computer went up about 4 MPG for about 100 miles. I realize that the displayed results are not accurate, but I have a feeling that some fuel injection curves were reset by the act of flashing the computer. My local dealer has agreed to help me look into it.



It doesn't make sense that Cummins/Dodge gets better emmisions by increasing fuel consumption, but that appears to be exactly what is going on with the "third injection event" and retarding the timing... . Sounds like a band-aid to meet fed regulations. About like using MTB years ago... ... .



Sorry the rant got a little long... .....

 

[DPelletier]

The local dealer told me that he heard that Dodge has programmed several fuel curves in the computer (Changes at 5K, 10K, and 15K miles). I don't know if this is true or not, but I did see the most substainal increase in fuel mileage at 15K miles. Anyone else heard this?

We have heard this sort of thing before and although I don't have any information to support my claim, I personally believe that this is a fairy tale perpetuated by dealers to pacify thier customers complaining of low mileage. I would expect (and have experienced) a small increase in economy and performance after breaking (15,000 - 20,000 mi) on the order of 5% or so.



Dave

 

[CJEliassen]

My computer is showing 16 and thats with some towing and hard accelerations. I haven't filled up my first tank, but that will be today and I will let you know what the hand calcs come out too. So far, I have been impressed.



On my 97 I had 255/75 BFG's and the miliage was around 18 avg. I switch to Bridgestome Revo AT's 235/85's and the miliage jumped up to 20 avg. I will also say that the Revo's are the best tire I have ever owned. They were awesome in rain, snow, and quiet on pavement.

 

[dawall]

Info on my fuel economy to date; 7989 miles, total avg fuel economy since puchase-15. 6 mpg.



~1000 ttl freeway miles, ~700 ttl towing miles with (2)~5000lb trailers, a utility and a three horse GN trailer. I live in a hilly area. 17 miles and thirty-five stoplights with no freeway driving to our biz.



BTW neighbor has 91 dodge w/auto and 1999 dodge w/manual, says he avgs ~16mpg in both.



Dan

 

[CJEliassen]

I think we need another gear. It would be great if someone can out with a gear box you can attach to the rear of the transmission that would allow you to select between your normal 3. 73 or 4. 10 and a 3. 21 for unloading driving in two wheel drive.

 

[WNowlan]

Here is a link to a double OD. My neighbor just had one put on his truck. I have not talked to him as he has been out of town. He paid about $3000 installed. He has the same truck as I do. 3500 4X4 SRW 48RE 4:10 gear.



http://gearvendors.com/