Where to Start?
 

Where is the best place to start when looking on improving fuel milage. I have bone stock 6.7 I have read a lot about deleting this or deleting that. Im not looking at deleting anything due to the fact that I don't want to loose my warranty. I do mostly city driving (stop and go from light to light and highway driving a couple of times a month) None of this is under load all empty miles. I bought the it because its a freaking cool truck. In the near future I will be hauling horses. Suggestions please. Thanks

If you want to keep warranty then you can't delete anything. That simple. Stock mileage sucks compared to the 5.9.

There is not really anything you can do. The muffler is a straight through design so nothing to gain there. Aftermarket air intakes probably won't do anything by its self. I'd just make sure the filters stay clean use the exhaust brake and tow haul mode when traveling local.
My 04.5 wasn't really too much better locally. It did much better on the highway because I had a smarty, aftermarket exhaust and air intake sytem. I could get a solid 20mpg on highway empty. This truck is about 17mpg. Even deleted trucks only seem to see a 2-3 mpg difference. I also will keep my warranty and stay stock.

Thanks for the input. I understand I cant delete anything. There has to be something though. What about exhaust, tuner, air intake? Would not changing the shift points and rpm limits help fuel milage. I use to own my own 18 wheeler that had a 60 series detroit. Just changing the shift points and rpm limits helped out a lot. I'm new to the small diesel world hence the questions. Again thanks for the input.

About the only thing you can do if you don't want to delete is to stay easy on the throttle, keep your speed between 60-65mph on the highway, keep your tires properly inflated, run high quality synthetic oil in your engine, transmission, transfer case, and diffs. Don't forget about your air filter.

Next up is to look at areas to trim weight. If about all you do is drive around town, leave the spare tire in the garage, only fill your tank half full. Whatever else you don't need, remove it.

The truth is, without deleting, your mileage is going to suffer and some stuff above may not be doable for various reasons.

If you really want more mpg, delete, you will be happy you did!

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+ 1 to the above, also for highway driving you can unplug the electrical connector to your EGR valve. That prevents the valve from opening and some claim it causes the ECM to nix the 4th injection event. I see an immediate jump of 2-3 mpg when I do this. Keeps your oil cleaner too. Just don't drive around town with it unplugged or your DPF will fill up. Shouldn't effect warranty. MIL goes out a few engine starts after you plug the EGR back in.

+1 to SOhappy's post about the EGR. Before I deleted, I drove about 12K miles or so with the EGR unplugged and saw an immediate improvement in MPGs. I don't know about the DPF plugging since it never happened to me driving around town back in MT on when I was in Texas and Southern NM for training. I would go a couple weeks without ever getting up to highway speeds and never got an indication that the DPF was filling up. Perhaps during that time, it wasn't enough to fill it up, but my MPGs never indicated otherwise.

You may be able to change your exhaust to a bigger one with a larger DPF, but I don't know if they are out there for our trucks. DPF's alone cost thousands of dollars. The MSRP on the factory catalytic converter is nearly $2500. I can imagine the DPF and everything else you would need would put you over well $8K - AT LEAST. Not sure if a larger exhaust would require new parameters in the ECM either. Adding a tuner = POSSIBLE loss of warranty - so you might as well delete. You could get an S&B or similar intake without affecting warranty (despite what others say - reference the Magnuson-Moss Warranty Act - which really could be applied to tuners as well - there is another thread discussing this so as not to get to far off topic).

In regards to the air filter - I am a bit on the fence if my S&B really made a difference and have thought about putting the stock box back in, installing an AMSOIL air filter and cutting a large hole in the box. Deleted with the stock box my max MPG was 22.7 on the a road trip to Texas. With the S&B I believe it was around 20MPG on the same route, different time. Others have stated the stock box is better so I really don't know. Just my personal experience. The S&B really cleans it up too. If AMSOIL made a big enough cone-filter (they don't) I would try that before going back to the stock air box.

Changing the TCM parameters may help, but you risk losing the warranty on the transmission. Dodge/Cummins has really limited what you can do to our trucks. Even though SEMA and the Magnuson-Moss Act was intended to benefit the consumer, it appears most people don't have the will, nor the money to fight even if in the end you win and the manufacturer has to pay all your expenses.

A friend of mine bought an '08 MC a couple years ago but refused to delete so it didn't affect his warranty. After multiple problems and tired of the bad MPGs, he finally went to a local Cummins shop and had the deletes done and hasn't regretted it since. I waited until about 17K miles after researching for months and weighing the pro's/con's and long term benefits of keeping my engine clean of its own by-products and figured it was more beneficial to delete. Almost 52K miles now and no problems with the engine.

Best of luck to you on achieving your end goal, but in my opinion, the best MPGs aren't achievable with stock exhaust.[guitar]

Get some kinda of box cover..

I drove many miles, both highway and city, with my egr unplugged with no hint of the dpf plugging. I monitored dpf pressure and regens, pressure never really changed and the truck still regen'd just like before.
You will lose remote start with the check engine light on.

Jeff.

Agreed! Like everyone else said, slow acceleration, bed cover, tires inflated and regular maintenance on fluids and filters. I would advise using your exhaust brake whenever possible. This will not only reduce the wear on your pads and rotors, but will also help clean out your turbo, which will effect your mpg. However, do not use your exhaust brake when driving on rain, snow, or ice. Although some do, it is not worth the risk of having your tires lock up while you are braking. Good Luck!

We would only get to use that engine brake in Alberta if no ice, snow or wet roads for 3 months of the year.. [dummy]

I'm not convinced that even deleting will help your fuel mileage that much. My truck is deleted and I still only average 12.4 mpg for mostly city driving. Granted, I'm running 35's, but still.

Thanks for all the input.