Just turning 30,000 kilometers and hand calculated I am getting 20.6 u.s.mpg [3.78 liter = one US gallon] and thats with the majority in the city on the last two tanks. I seem to be getting better mileage every 10K. I am not driving the truck very easy either.

 

Last night I filled up and checked the mileage 20.1 mpg. I have 5000 miles now and going to change the oil this week. Not too bad for a stock truck with very little highway miles. I'm really sorry to hear you guys that have bad mileage.

 

This is written for bigger trucks, but it has a lot of information of interest to those with low economy numbers:

http://www.cummins.com/na/pdf/en/pro...on_for_web.pdf

Having read every post written about mpg and 600s, I have a theory that I will humbly submit to this forum. Could it be that the cam timing is off? Production line parts do vary to some degree. I race motorcycles and it is common to have the cams degreed for better performance. If your cam timing is retarded the valves will open and close too late relative to the piston position. If it is advanced they will open and close too early. (If you have dual cams things can get way out of whack, leaving you way down on power and always trying to stretch the throttle cable to its limit.) I don't know how Cummins builds their cams, whether they are gear driven or chain driven and whether the mechanism is pressed on, bolted on or welded on, but if it isn't set exactly right, you could be paying for it at the pump. And it wouldn't show up on a diagnostic computer, either. Everything will be working exactly as it should, just not exactly when it should.

I don't know if this is even a realistic possibility, or, if it is, whether it is something that could be checked and fixed. I also don't know what percent error is acceptable in the cam parts, the timing position sensor, etc., but I figured they could stack up. I'm just throwing this out to see what comes back.

 

Just made a trip down the coast of Mexico and back. Driving around the 100kph (62mph) limit I got 22-23 mpg for 2200 miles - hand calculated. Very few miles of city driving. Sea level and air temps upto 102.

2004 555 4WD 2500 3.73 Stock tires.

 

Brother's "popping" truck is '03 SO, Quad cab, 4X4, 47RE, LB, 2500 with canopy, Tru flo air filter.

 

Well, mine is bone stock. I have 1500mi and the best I have gotten around town is 13.1 (the last tank so it's still improving). This past weekend was my first road trip (400 mi r/t to pick up my daughter from college for the summer). There was a lot of junk in the truck for the return trip, but I can't believe it amounted to more than few hundred pounds. Anyway, I got a hand calculated 16.3 of almost entirely highway miles. I was at 70mph most of the way (around 1950rpm). I'm still hoping for some improvement. It still doesn't come close to what I was getting with my PSD.

Neil

 

I average 20 - 21 mpg on the hwy if I keep it under 70. Mixed city/country gets me around 17-18 mpg. With 4000 lb boat in tow, I get 15-16mpg.

I'm very happy with these numbers. Especially with only 4000 miles on the clock.

This is with an '04, 555, 6spd, 4X4, 3.73, QC, LWB. All stock. Maybe I'll be getting 22.5 mpg when she is all broke in.

FB

 

My mileage is very similar to Rumbles, much higher than most of you, and for good reason. The Canadian Gallon is good for a couple of points, if you guys want to make yourselves feel better use the Canadian for you conversions!

 

I just back from a small road trip over the weekend. Topped it off before I left and drove 495 miles. When I got back I filled it up again. It took 22.3 gallons, thats 22.2mpg. I drove the entire way with the cruise on 65mph and all highway miles.

 

congrats Rumble... You are one of the very lucky few
enjoy

 

583 mile trip- 21.93 mpg
From near winston-salem NC to the beach, stopped at one set of in-laws on the way down and the other on the way back. some 70mph some 65, some 60, driving around to eat and stuff at the beach and going through a couple of towns,
I was running the volumizer on level two. the overhead said 24.7 but it was actually 22. I think I get better mpg not using the volumizer(which I would expect) I did this to check the computer against the hand calc.

Have a trip to orlando and the on to the keys in July, I'll check the variation on that trip.

currently 22,000 mile on the truck, not a year old yet. At 55mph I can get 25 mpg but I don't drive 55.

 

Just to let people know I did my calculations to the US gallon which is what our overhead console reads in even in Canadian trucks. Our so called metric version is calculated on the overhead using litres of fuel used per 100 km driven. Rumbles

 

I just got back from about a 7,000 mile road trip, and hand calculated milage for various parts of the trip.

Speed plays a much bigger role in milage than I figured. Over the tetons and yellowstone often in 5th gear and below 50 mph I got over 22 mpg (included both up and down the mountains). Get into a flat 75 zone and run close to 80 and it drops to 17 point something.

Running local roads with a mix of 60 mph to 70 mph it seems to run 20 to 21 mpg.

Anyway, speed can make about a 6 mpg difference in my truck, where hills, or a heavy foot on the on ramp doesn't seem to make much difference.

 

hi guys i have a 04.5 600 cummins and it gets around 19 mpg in town (alot of time it goes to around 22-23 mpg in town if im taking it easy.

ON THE HIGHWAY= ok

if i ignore the LOUD and very NOTICEABLE vibrations from the truck heh, it gets 16.8 mpg doing 80mph on the highway :/

I just got back from florida and on the way down i was getting worse mileage, on the way up i got like .5 miles better (while going faster than last time)

the trip to florida put on a total of 2200 miles there and back in 2 days heh

 

I have been keeping track of my fuel milage since the day I drove it off the lot back in Dec 2003. Coming up on 22000 miles and the overall avg is 20.67 mpg. Always hand calculated, because I don't have a overhead computer. I drive about 60%hiway and 35% city, and 5% hauling ****. (my clutch nows slips on 4/3 with the tst). 2003, 4x2, LB, 6-speed with 3.73's. I've drove 770 miles on one tank before(I think it took nearly 40 gallons to fill it up that time). If I drove it right, I'm sure I could easily squeeze another 1.5 mpg out of her. Also my truck was supposed to come with 245 tires, according to the sticker on the door, but the dealer had put after market wheels and 265 tires. I verified with gps that my speedo is 1-2 mph off at 70 mph (speedo says 70 and gps says 68-69 mph. Its hard to hold steady to get much more acurate). I normally drive 70 -72 going back and forth on hwy 51 in west Tn. My 2001 QC dually with edge comp, 275 inj, auto, 4.10 only got about 16-17 for the same track(Dyersburg to Memphis every day). I'm liking this truck much better.