help...06' poor MPG

[Burner]

Hey fellas... can anyone help me? I've had a Dodge before (93) and it got pretty dang good fuel economy. However, I ditched it as it fell apart around me. Sad to see such a great motor/drivetrain go for scrap because the truck was a POS. Anyway, I've had an 01 Ford PS, an 02 Duramax and an 03 Duramax that all got ok fuel mileage. I wanted to try a Dodge again. I was aware that MANY improvements have been made to the body and chassis. I stepped up and bought a new 06' 3500 4x4 Dodge dulley. I wasn't sure how low the MPG would be from the start but I knew it would be "kind'a" low. This truck had an easy first 1,200 miles. I would start it up wait about 2 minutes and take off and I stopped about the same way, cooling for 2 minutes. I really ripped into the truck a few times after 1k. I installed about 2k worth of stuff to work with. ..... now @ 7k miles it's just sucking wind. I dynoed the truck on David Dunbars dyno 250+HP and 470+TQ. The truck just will not perform? I mean it seems to pull ok but it's eating fuel like there is no tomorrow! I pulled 18,000 lbs about 330 miles and got 8. 7 MPG @ 125 hours and 3,200 miles. I pulled 7,700 lbs 370 miles just the other day and got 8. 1 MPG, @ 235 hours and 6,800 miles. Can someone tell me WHY this is happening? Can someoen give me a list to check? My "in-town" mileage is about 10, yeah I said 10 MPG in town. My in-town driving is 50/50 Hwy/street mix. I do not have any mods, nor do I want any as yet. I'd like to have a good truck that got got fuel economy.



..... why would I want to have this Dodge with "less HP" than my Duramax and "worse" fuel economy? #@$%!





Someone please help... ... . :{

 

[Wiredawg]

Not much info...

Do you have auto or sitck, 4. 10s or 3. 73s?



I don'e have an 06, but here's what my fleet avgs:



'93: 18 mpg empty; 11 pulling 10K lb trailer



'02: 14 mpg empty (it weighs 9. 7K lbs empty) I could get more if I drove it at 65mph and was easire on the starts and it's always gotten that after 75K miles, no better; I get between 8 and 11 mpg pulling 17K lb 5th wheel depending on wind, grede and speed.



'03: Started out around 14mpg then eased up to 17mpg at 10K miles then at 20K added another mpg.



Foot pressure is one of my failings... I usually get 2 - 3 mpg less then most folks driving the same setup.



Hope it get better, Wiredawg

 

[Burner]

The truck is a 3500 CC 4x4 Dulley with 3:73's and stock tires. The towing numbers come from +/-4 MPH of the speed limit. The empty miles are +/- of 8MPH of the posted speed limit. I'm a little hard out of the gate but I don't fly down the road.

 

[BILLUA]

That mileage is LOW. I have a 05 same truck as yours... I now have 20k on it and am getting about 12 pulling 7k and 15 around town... My mileage was about 12 around town before with about 12 k on the truck. These things take forever to get up to their best fuel mileage.



That said, I would still take this truck into the dealer and have them diagnose your poor mileage.



Cheers, Bill

 

[macdaddy]

That mileage is LOW. I have a 05 same truck as yours... I now have 20k on it and am getting about 12 pulling 7k and 15 around town... My mileage was about 12 around town before with about 12 k on the truck. These things take forever to get up to their best fuel mileage.



That said, I would still take this truck into the dealer and have them diagnose your poor mileage.



Cheers, Bill

Ditto here. same truck same mileage only a stick (5600) and 4:10's.





Burner, swap out the air cleaner with at least a drop in from AFE, and either remove the muffler or replace it with a better flow through design. Also I would recommend having your dealer check it out as well.



Mac

 

[Burner]

I too thought that "might" help so, I changed the oil & oil filter again, the fuel filter and the air filter using NAPA Gold products. Afterwards, I did go to the dealer and they (Susan Schine in Pelham, AL) were VERY nice to me. The tech, Bradley, broke out the new StarScan tool and swiped the whole ECM... . dang, even swiped my VIN! ... . BTW, a truck will not start without a VIN. Anyhow, I did get a new program installed. I don't know what it'll do but so far it's the same or worse.



..... Whoever has an 06 with the same problem must come forward. If DC has a problem with enough complaints, it will be fixed. However, if folks just accept it..... DC won't do jack.



..... it costs me at least 20 to 30% MORE money in fuel to drive this truck than my old Duramax. It costs about 20% MORE money in fuel to drive than my old PowerStroke Ford. ... ... . and the crazy thing is that it costs about 45% MORE money in fuel to drive than my old 93 Dodge! #@$%!

 

[DJennings]

On my 04. 5, I noticed immediate 2 mpg gains when I replaced the exhaust with a free flowing system. I also ran an AFE intake and edge juice, but those maybe added 1mpg. I personally think the exhaust will do the most for you. When I traded it, I could get 18 at Interstate speeds and 15 in town.



My 06 is doing better than yours, but it is a SRW. I'm getting 11-12 in town and 14-15 hwy with 500 miles on the odometer unloaded. Haven't had a chance to hitch it up yet.

 

[BHolm]

I don't think it is right to suggest he start modding the truck. Even if you are only talking an air filter and muffler. That milage is really low and something must be wrong. I would try and persist with the dealer and DC.



My '06 was a little low right off too. Started around 14 mpg and now at 6k with some towing and a bunch of highway it seems to be coming up around 15-16. My '05 was up to 17-18 empty (QC LB SRW auto 3. 73) at 30k miles.



I think one mistake people make is to baby the engine when new. The manual states that NO break in period is needed for the Cummins. The rear end needs 500 miles. Right after 500 I hooked up 15k and pulled some grades. Last week I pulled I-70 Denver to G. Junction with 1500 lbs in the bed. I ran it hard up the hills, full boost as long as I could keep traffic out of the way. These engines take so long to break in because we use them in a much lighter duty application than they are designed for. Run it hard, run it hard often. Either the milage will come up or what ever is wrong will break and you will get it fixed under warranty

 

[tgrfan2]

There must be something wrong with it. Got my 06 Friday and filled it up at 47 miles. Did 117 miles which half was on I 20(75-80 with occasional "tests" up hills) and 40% on two lane at 60 the other 10% in stop and go driving in tow mode(just playing)@ 35-50. It got 18. 6. I know this was a short drive but the truck has lots of power. If the dealer can't help you they can arrange for you to take it to Cummins. Most have dynos they can test it on.

 

[Burner]

Please tell me how to get this done. I'm really at a loss.



How do you get the Dealer to set-up a deal at Cummins? I guess they will do some kind'a compression check? Heck, It'd be nice to see what the lift pump was producing, what the rail pressure is and what the Injector ballance rates are. Could the engine be built a little off and the computer is making up for the difference?



... ... ... just think, if I get 12 MPG on the HWY and you get 18MPG the difference is 6MPG or 50%. You can drive 630 miles on 35 gallons and I can only drive 420. Work'n the numbers on 2. 50 per gallon that's . 1388 cents per mile for you and . 2083 cents for me. It doesn't sound really bad until you look at the big picture. In 50,000 miles @ 18MPG you'll spend about 6,940 dollars on fuel and I'll spend a whopping 10,415 bucks..... that's 3,475 dollars *spent and gone* for no reason.

 

[tgrfan2]

I was doing a little investigating for a friend with similar problems on an 04. I was told a factory rep could "make it happen" if Dodge dealers found no problem. As I said, most Cummins shops have their own dyno. It is pretty easy to check your truck and compare to the norm. With that kind of fuel economy and power problem I would be tempted to take it in on my own to see for myself.

I don't recommend the Cummins shops for modified 12Vs though. My experience is that they are too traditional in their thinking. I wasted about $500 on my 95 there trying to find a problem a #6 plate solved.

 

[DieselLady]

You said you installed 2k worth of stuff to work with..... What do you mean. Is this stuff all installed as Mods or is it stuff in the bed, extra weight or what. This could make a difference. Also are you doing the math at the pump or are you going by what the computer tells you? Sometimes those computer MPG readouts need time to learn and are not accurate. I have a 98 Newmar Mountain Air motorhome with a 12 valve 8. 3 cummins that gets 8. 9 mpg doing 65 to 70 down the road. I can hardly beleive that the 06 only gets 8. 3 towing.

 

[Burner]

I only use the *display* as a refrence. I divide the number of miles driven by the amount of fuel I replace. This is my 5th Diesel truck... . worst MPG so far. And the 2k worth of stuff..... 750 for the ICI bars, 500 for the spray liner, 400 for the B&W hitch, 700 for the B&W fith-wheel, 120 for the tint, 170 for the DODGE rubber bed mat, 200 for the brake controler and 100 for 4 DODGE mud flaps. ... . I think I'm over the 2k mark. As it stands, I'll never get my money back out of it so, I better stop before the hole gets too deep.

 

[DieselLady]

So no mods..... You don't live in the Rockies so you aren't dealing with altitude. If your air filter is clean and your not getting a lot of black smoke and it's not leaking fuel than just for the heck of it I would pull the dip stick. The last time I heard of such bad fuel economy was in a Dura Max with Leaky injectors. He was going from 15 MPG gradually down to 10 mpg. Than one day he pulled the dip stick and it read 4 inches too high. Never heard of it in a cummins but it doesn't cost any thing to try. Does the 06 come with a CAT Converter or not????

 

[Burner]

Everything checks "OK". I've checked the oil 4 times in the last 500 miles. Oh yeah, every time it's checked is in the morning every time, no varibles.

 

[Huskerman]

Burner,



I am not here to lecture you and I don't claim to be any kind of expert. All I can do is give you my experience.



1) Anything and I mean ANYTHING over approx. 67 mph and you will see your mileage drop SIGNIFICANTLY!!! I know because I am probably the most anal person around when it comes to fuel mileage. Ask gonehuntingagain on the 2nd gen forums.



2) Your 4. 10's are going to make a difference, as is your auto if you have one. I didn't see your answer about which transmission you have.



3) Comparing an 06' to a 93' is a serious mistake IMHO. You are comparing a motor with approx. 175 hp to one with 325 hp (advertised) ! gonehunting again used to have a 94 and he got 20 around town delivering pizzas! I got 20 on the hiway in my 99' and 01'.



4) Comparing your city driving to anybody elses is a waste of time and will likely drive you insane unless they literally drive the exact same route as you do. It all depends on the stops, the speed limits etc.



5) If you are pulling 18k and getting 8. 1 mpg, I would say that sounds pretty good to me. I know people who pull 1/3 that weight and only get 9 in their gassers.



Lastly, and once again let me say that I don't mean to lecture, but there are folks that will swear up and down that if they don't pull their 30' 5-ver at 80 mph on the free way they will "get run over" and then they complain about getting crappy mpg. I say if you are pulling a 30' trailer at 80 I would worry more about your airbags and seatbelts than your mpg.



Huskerman

 

[jimnance]

That mileage is LOW. I have a 05 same truck as yours... I now have 20k on it and am getting about 12 pulling 7k and 15 around town... My mileage was about 12 around town before with about 12 k on the truck. These things take forever to get up to their best fuel mileage



That's about where I'm at. 15 MPG around town and 9-10 MPG pulling 14,500 at 60-65 MPH.



I wonder if you have an injector problem. Your economy does seem kind of low. However, a 3500 Dually with an auto is almost the worst combo for mileage. Only 4. 10 gears would make it worse.



I figure the auto and dually are costing you about 2 MPG. If you aren't getting 15 MPG empty with 50/50 driving you should have the dealer look at your truck. Ten MPG empty is too low.

 

[Burner]

Huskerman... ... I'm sure you mean well but I don't think you quite grasp what I've said.



1. 67 is not a speed at which most folks travel. On my last long drive, the trucks that "passed" me were pulling trailers and I wasn't. Yes, there were Ford, Dodge and GM duellys... . they were all getting the same MPG or better that I was/am unloaded!



2. I do not have 4:10's, I have 3:73's with an AUTO.



3. To "better" a truck it must be compared to another... ... . I compared this 06' to a 1993, 2001, 2002 and a 2003. It is the relationship between two like objects that sets them apart. How could I have any judgement of this truck had I not had 4 Diesels before it? ..... yes, all trucks listed were/are Diessels! I've been in construction all my life. I only have a couple of gassers... . the rest are ALL DIESELS! ..... BTW, the truck only has about 250 RWHP. The big "325" is a joke. Look at the HP/TQ graphs posted here and elsewhere, see the difference... there isn't much between years in TQ. And, very little between 2003 and 2006 which are commonrail set-up's.



4. I agree... . to a point. I am "trying" to get decent MPG out of this dang thing. In either direction I live 2 miles from the Innerstate with no lights between me and the big top. 90% of my driving is Innerstate, 90%... ... ... ... ... ... 90% of my driving is Innerstate.



5. 8. 1MPG is "ok" in a Diesel? You gott'a be nuts! Hell, the 475CAT in the Kenworth will get that with 18k on it's back! My 03' Duramax got just over 11MPG pulling *MORE* than 18K! And I drove the mud out'a it! Stupid for me but with that load I ran 75 to 85MPH, I was in a hurry.

... ... Why are you even bringing up "gas" at all? We all know about gassers, we bought DIESELS, right? Heck, my Suburban has an 8. 1 liter (496ci) and drinks gas pretty well but not like this DODGE with a CUMMINS DIESEL in it.





... . I generally don't fly down the raod. This last trip was for a friend and I had plenty of time. I drove the speed limmit or with-in +/- 2 mph of it. I was turning around 2,000 RPM the whole way home..... 365 miles worth. And yes, I had to stop for fuel about 3/4 of the way home. My 38 gallon tank was dry... .....

 

[Huskerman]

Burner,



I understand your frustration, I really do. You could say (with a high degree of accuracy I might add) that fuel mileage is an obssesion of mine. To the point that I have never understood WHY Dodge/Cummins felt the need to increase the HP in the first place. But, I digress and that's a topic for another post.



I will try and respond as best I can to each of your points.



1) I realize that most folks don't travel 67. Heck I don't even go that slow if the speed limit is greater but then again, I don't tow either. I was just pointing out what appears to me to be the sweet spot.



2) My mistake, I apologize.



3) I said "... 325 (advertised)... " because even I am smart enough (albiet just barely) to recognize that it's not 325 at the wheels. I still think it's difficult to compare the years you listed to an 06' as the trucks and engines are too different IMHO.



4) 90% and it sounds like an easy drive for even the 10% not interstate!! You definately need to keep hounding your dealer.



5) Look, I really don't want to turn this into anything personal. If I offended, my apologies. The folks I know with Fords that pull 5-vers all get 10 mpg or less. The one person that I know personally that tows with a 3rd gen Dodge pulls a TT that weighs considerably less than 18k and he only gets 10. 1 mpg.



As for my comment about towing speeds, the only point I was trying to make is that I think people who tow large loads at high speeds and complain about the fuel mileage are missing the larger point about safety. I was not trying to offend or accuse you of anything I just took the moment to get on my soapbox. Although I don't tow anything significant myself, I have spent a lifetime around people who do AND people who have to respond to the accidents caused by unsafe drivers. I can't remember the last time I heard or read about an accident that involved somebody towing that didn't include the comments "speed was a contributing factor" but once again, that's not the point of your post so I will move on.



You truck WILL break in and you WILL get better mileage. In the mean time, keep working with your dealer. One of the big problems is that the automakers aren't required (unfortunately) to list city/hiway ratings for 3/4 & 1 ton trucks. Although I am generally against gov't regulation, it would be nice to know what we should expect from these trucks.



Good luck with your truck!



Huskerman

 

[Burner]

Thanks... .....





I'll try to get'er done..... try. I've battled like this before. I'm just about ready to "swap" trucks. I've found out that agrivation and stress are far more expensive than swap'n trucks. Maybe the Dealer will be kind and let me swap it for a different truck... I doubt it but maybe.





... . strange thing is, once I get it where I want and broken-in..... I'll bomb it. :-laf