Phil705

I know this is not a new topic, but I am disappointed with my mileage on the 2005 Dodge 3500 with the 5.9 Turbo Cummins. I've got about 53,000 miles on it, bought used.

According to the computer and my fuel bill, I'm gettting at best 18 mpg on the road, about 16 in mixed driving, and 12 with the camper on board. (But I love the truck!)

I've heard claims of 20+ mpg with improved air intakes, chips, a new VP44, and adding some PowerService. The tires are properly inflated, and the air filter is clean. I am not using synthetic oil at present. I try to go easy on the throttle, and accelerate slow and steady.

I am new to diesels, and not particularly mechanical. I tend to be skeptical of manufacturer claims unless you guys have some experience with real improvements.

What would you do first, second, and third? Many thanks in advance.

Phil705
Winthrop WA

Dojman

Your mileage is similar to what we are seeing with our 06. Will pull a house, but likes fuel. Funny how we get spoiled, I use to drive a 1/2 ton, V8 that probably got 10 mpg and wouldn't pull squat.

tesla440

what you're getting is similar to my mileage as well. The people who get 20+ MPG are ones that just travel freeway only and drive mostly around 65mph. With the torque converter locked & at 50mph I get get like 23mpg. But I can't drive very long distances like that.

The best way to get better mileage is to drive differently. I know that this will sound funny, but go to a hybrid meeting. They're all about mileage & different tech to go further on the same about of fuel. They may get 50+mpg, but they don't drive a 8000# brick either.

Otherwise Bully Dog has a driving coach that is said to give you about 20% better mpg just by driving differently.

rogers259

First off your truck has a CP3 not a VP44. Changing out the injection pump is not going to change your fuel mileage.

If your wanting better performance look into changing a few things. First thing is to get rid of that stock air box. Do the ******* Whistler upgrade or go buy an AFE air intake system. That will help increase the air into the engine a bit. Second thing, go buy a Smarty programmer and install that on the truck. You'll see a noticeable difference in power, performance with that. One word of caution...you don't have anything done to your transmission so I would not take it above lvl 3 till you upgrade your tranny.

The above two things will help with the performance of your truck. Notice I said "performance"...the best way to increase fuel mileage is controlling the right foot. You have to control the way you drive, slow down and you'll increase your fuel mileage.

Also make sure your hand calculating your fuel mileage...don't trust the onboard computer.

Phil705

Thanks for the realistic replies. But more questions:

Is there a most-economical RPM or speed for highway driving?

Does driving in 4 WD take more fuel than 2 WD? ( we have 8 miles of dirt/gravel road to get home)

Should I continue to use the tow/haul feature when loaded?

p035970

Not to start any type of disagreement; but for a 1 ton 4x4 truck, that is very good fuel mileage. Its at least 3 MPG better than a comparable gas rig. Most folks expectations are way too high after hearing others inflated mileage reports. Most people seem to tell their best tank ever when asked their average. Your numbers aren't that far off of similar trucks from 20 years ago (12v) and a lot better than the old Chevys and Fords (everyone states the old diesels were far superior in MPGs). I've been driving diesel PUs for over 20 yrs and for the increased performance from the factory these days, the pre 2007.5 s with numbers like yours are very good compared to other trucks on the road. Sorry for the long post, but thought it might help you.

Dodgezilla

1800 rpm is the sweet spot on most of these CTD trucks. Your mileage is actually pretty good. I get my best mileage on the highway, without many hills, and at 60 mph. Faster than that and it starts dropping quick. At 75-80 mph I'm almost back to what I get in town.......

AaronT

Your mileage is pretty good, slightly better than mine is. If you purchase addons it is doubtfull you would recoup the money spent on them unless kept to the minium. If there is no need, leave it stock. Justasayin.

sikboater

Well that is about what I get also.... I will get about 18 around town and 13 - 14 pulling the TT trailer. Just got back from a trip to Yakima WA (averaged about 13 on the freeway over (I-90) there and 14 over White Pass on the way home). The best I have every gotten was about 21 on the freeway not pulling or loaded with anything. I think that some of the claims in the 20 mpg range are from 2wd drive trucks also... My overhead is always about 4 mpg off but I hand calculated the values above.

Foxborough

The fuel mileage really drops off when you go 2000 rpm and higher. I find 1900 rpm = 71 mph and I get 19-19.5 mpg. But you really have to merge and accelerate boringly (not a word but it applies here) . I always get on it occasionally which is probably why I never get to 20 mpg. But in the city I get around 15 mpg. FYI

Gmanndodgeguy

I have the same truck with 3.73 gearing and drive in mixed traffic, city/hwy. I get 14.5 to 16 on summer diesel driving to keep up with traffic. If I baby it and drive/accelerate really slow I'll see close to 20mpg. Towing is a complete different story though. I tow a 8000 lb trailer and get 10-11 if I'm lucky at 62mph. If any hills or wind I'm getting 8-9 towing. You're right in the ballpark for mileage numbers. You should be happy with that. Like others have said, back off the go pedal and watch the numbers increase. Use the overhead lie-o-meter as a guide to gage whether you're going in the right direction.

cheers

berok

Phil, Read my sig. That's what I'm running with and am getting a hand calculated 22-24 HWY empty. Up to 26 during the winter. But when I pull my boat it drops to 17mpg...

berok

When I first got my truck new, we drove from abilene tx to shreveport LA and about 3/4's of the way back to abilene before we had to fill up. I got a little over 725 mi out of that tank.....

Dieselpower73

I found going to a cold air intake and a plug and play chip 85 to 100HP, makes a difference. I gained 1/4 tank on my 430 km trip to work.

Dieselpower73

I meant to add. I have done this for 5 other people and they have also noticed a difference.