06 mileage sucking and my theory

[Cummins Cowboy]

after over 14k miles, and they haven't been totally easy miles my '06 is consistantly getting at least 10% less fuel mileage than my '02 got, it seems like every new dodge diesel I get the mileage goes down, first gen was great, second gen not as good and the '06 unless I was towing a hemi would be a better choice which is down right sad. so my question is with all the emissions crap where is the fuel going because it sure as heck aint burning up in the motor and creating power, infact I have noticed a pronounced black soot area on my lower quarter panel and bumper that I never had with my '02, I also stomp the pedal at night and get a bunch of haze out the exhaust, so my theory is the truck is actually polluting more because of all the controls that are placed on it, my theory also is that the EPA tried to eleminate one aspect of emissions and created more emissions of a different type. in Utah we have been consistantly paying . 40 or more for diesel over gas, I hate to say it but with the mileage issue and the price of diesel that will flatout not go down around here this may be my last diesel truck. so will someone please explain to me how its possible for a truck to burn more fuel to do the same thing and still pollute the enviroment less??

 

[betterthanstock]

you're right.

It pollutes less NOx (EPA seems to be obsessed with it, but not with CO which kills so many people), and lots more CO, CO2, Methane (unregulated, because the catalysts cannot neutralize it, which is supposedly hundreds of times worse for global warming than CO2, if you believe in that).

So basically, to reduce NOx, the engine has to produce CO, and HC (unburned fuel), which then reacts inside the catalyst to netralize the NOx.

So if you remove the catalyst, you may die of CO poisoning from a diesel. (not possible with older diesels, they have too litle CO, and too much oxygen to kill you, but the NOx will irritate you, and may cause asthma)

 

[Mhannink]

betterthanstock has a good measure of it i think. diesels by nature produce high noz emissions while producing low hc and co there is useally a good amount of 02 as well and co2 is gonna be high because the motor runs efficently. the epa is for some strange reason cracking down on nox emmissions. in order to do that you have to cool the reaction in the cylinders and cool the exhaust. nox is formed at temps of about 2500 degrees if i remember my emissions lectures right. now if you flood the cylinder w/ fuel and make it run poorly you will cool the temps down to reduce the amount of nox. in doing so though you one have obviously put more fuel to it so you are loosing some that way. at the same time the higher fuel content makes for a poor running engine which lowers your co2, 02, and nox emissions. in a sense you are running rich now. this also rasies the hc(unburned fuel) and your co emissions. course ive basically said the exact same thing as betterthanstock.



the poor fuel milage as i understand it comes from the final event that basicaly injects fuel in the exhaust to help burn up the all these emmissions. im not sure if im right or how its supposed to work but thats a rumor i have heard.



in yeah the fuel milage is dropping as the trucks get newer. some people hear say that it has nothing to do w/ the emmissions but w/ the power level i disagree but thats a different thread.

 

[TMoe]

Funny, I was thinking about this same issue on my way to work this morning. I feel the same and almost bought a bowtie gasser as my dads 2000 6. 0 pulls a 32 ft 5th wheel over 30 k miles with not one issue, power/ no E-brake sucks though. What sold me was the overhead said around 20, some highway some in town, on all the trucks I tested and I believed it. Buyer beware. Actual mileage cruising at 70 is around 17. I would get over 20 easy with my 01 in same route. I didn't like the steering or noise of 01 but I think I am going to miss it if my towing mileage is way less. I could pull my small 5th wheel at 60 mph and get 16 mpg, awesome, 14 at 70 mph. Someone fix this please. Get rid of the third event to clean up the oil and get the mpg back up. Just kidding. Wouldn't want to mess with the environment. Maybe a Franz bypass ****s-zu filter would help oil issue. Someone mentioned Dynatrac hubs for improvement also but seems to costly to me.

 

[DieselFiend]

Yes, someone please fix this!!! I got consistantly better gas milage with my 02 as well. Maybe Marco and Bob can work on something with their smarty. It would be nice to get that milage back. I think the EPA has badly bungled things up by putting restrictions on us light trucks when there are obviously more big rigs on the highway producing the kind of emmisions that the EPA is having a fit about.

 

[wyosteve]

Guys, you have to remember that 1st gens. were 160 hp. , 2nd gens. 245 and 3rd gens. 325. You need fuel to make more power. Having said that I think the mileage is great on mine for moving over 4 tons of metal and being able to tow 5 plus tons with it.

 

[DieselFiend]

If you've noticed, there isn't a huge milage difference with towing. I usually get 15 - 17 on the highway at 65 MPH. My fuel milage only goes down to 12 - 15 when I'm towing. This tells me that the engine isn't working that much harder regardless of the load. It's being restricted somehow. Something is a miss. With my 02, I'd get 20 - 22 on the highway at 65 mph and drop down to 12-16 while towing.

 

[p-Bar]

As said it's that third event of the injectors to keep the cat hot (that's what makes them work). I baby my truck around and when I romp on it it does the same hazy type smoke out of the exhaust. Some one needs to make a (test) box to get rid of the third event

 

[DieselFiend]

Couldn't agree with you more. Maybe the ECM nerds are listening.

 

[Cattletrkr]

My '04. 5 gets the same mileage as my '01 did. Best I ever got with the '01 empty was 19mpg, '04. 5 18. 4mpg. Both were short runs and never duplicated. Towing I get a little lower mpg, but I'm pulling a bigger trailer now and I have 80hp more stock.



Just talked to a neighbor the other day who has either an '04. 5 or '05, I don't recall which. He is getting over 20 empty if he wants to. Auto w/ 4. 10.



Some people say they get an immediate improvement of 2mpg when they yank the cat. If ULSD starts causing problems, I might just loose mine out of protest.

 

[wcjp]

Guys, you have to remember that 1st gens. were 160 hp. , 2nd gens. 245 and 3rd gens. 325. You need fuel to make more power. Having said that I think the mileage is great on mine for moving over 4 tons of metal and being able to tow 5 plus tons with it.

This is true of a stock vs stock engine. My slightly modified 96' had the same torque as my slightly modified 06' measured on the same dyno. The 96' averaged 19+mpg while my 06' averages 17mpg. The 06' is slightly heavier because it's a Mega vs CC. The extra 2-400lbs can't be responsible for the 2mpg difference. I was very close to having the Cam swapped for a Piers unit. Decided I needed the Exhaust brake more than mileage.

 

[cerberusiam]

As said it's that third event of the injectors to keep the cat hot (that's what makes them work). I baby my truck around and when I romp on it it does the same hazy type smoke out of the exhaust. Some one needs to make a (test) box to get rid of the third event

The 3rd event is part power and part emissions and works with the cam timing. JUST turning off the event causes major issues with the fuel delivery and power generation. It has been tried and weirdness ensued.



Now, iy you changed the cam AND retimed the events you may have a workable solution.

 

[pwr2tow]

These are unload, non towing mileages,

My 1999 got 16 MPG unmodified and 17 MPG modified
MY 2005 got 18 MPG unmodified, never modified it.
MY 2006 only has 3,000 miles on it and gets 19 MPG unmodified, It will not be modified because it has enough power.

They all are driven the same by me, and towed the same 5th wheel

Seems to me the newer the truck the better fuel mileage.

 

[Cummins Cowboy]

best mileage I have ever gotten is 14. 4 but that is on winter fuel and much of it at over 80+ mph. So I would expect maybe 16 or so if I am lucky, towing is where its really hitting me the 02 would get 11. 5 with the exact same load this truck gets 10. 5 or less, doesn't sound like much of a difference but when you get toward single digits it is. is there a way to convert our trucks over to what the 03's and '04s used??

 

[Bob Wagner]

Couldn't agree with you more. Maybe the ECM nerds are listening.

:-laf







Cummins Cowboy are you staying current on the DC software releases?



Marco can provide better fuel economy and lower egt's with his software's

 

[JHenry]

Funny, I was thinking about this same issue on my way to work this morning. I feel the same and almost bought a bowtie gasser as my dads 2000 6. 0 pulls a 32 ft 5th wheel over 30 k miles with not one issue, power/ no E-brake sucks though. What sold me was the overhead said around 20, some highway some in town, on all the trucks I tested and I believed it. Buyer beware. Actual mileage cruising at 70 is around 17. I would get over 20 easy with my 01 in same route. I didn't like the steering or noise of 01 but I think I am going to miss it if my towing mileage is way less. I could pull my small 5th wheel at 60 mph and get 16 mpg, awesome, 14 at 70 mph. Someone fix this please. Get rid of the third event to clean up the oil and get the mpg back up. Just kidding. Wouldn't want to mess with the environment. Maybe a Franz bypass ****s-zu filter would help oil issue. Someone mentioned Dynatrac hubs for improvement also but seems to costly to me.

I have an '06 with Banks Technicooler, AFE stage 2 filter, Jake Brake, and Dyna Trac hubs. I have 34000 miles on the truck. With each modification, I noticed a very small increase in economy, but with the Dyna-Trac hubs I noticed the most. I am very happy with the hubs, but p-o'ed at the sales rep. He owes me 3 t shirts and 3 caps and has quit answering my emails. Anyway, I can get 21-23 on the highway at 60, and 16-18 local driving if I have the front hubs on free wheel. I don't think that's too bad. JH

 

[Cummins Cowboy]

so how much mileage gain can the smarty give you??

 

[Jrissler]

I'm with you on the crappy mileage on the new ones.



I like the ride but it bite the wallet.



Last night I pulled a load grossing about 20,000lbs. and had some hills and kept it moving. 8 MPG. I've seen 7 already with it, thats BAD!!

 

[Cummins Cowboy]

I figure because of the EPA I am paying out nearly an extra $100/mo, if you figure the fact I am paying at least . 40/ga more for diesel than gas largely because of the stupid sulfur deal and couple this with the 10% reduction in fuel economy it doesn't take long to eat up a franklin.

 

[J&LRam]

my previous truck was a 2nd gen '01 2500 auto 3. 54 235/460 truck and averaged 20+ mpg on my 600 mile a week commute.

My '03 3rd gen 2500 NV5600 3. 73 305/555 truck gets 22+ on that same 600 mile a week commute and has for over 57k miles. I'm really impressed with the performance and ecnomy from this 3rd gen truck over the 2nd gen I had.

JIM