your mileage
10-23-2010, 08:17 AM
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your mileage
I bought a 2003 cummins that had a lot of work done to it right before I bought it. I have also done a few things to it to try and improve the fuel mileage. The truck has 3.73 gears in it and is an automatic 4x4.
The truck has the following done to it:
MBRP stainless 4 inch exhaust done by me
AFE stage 2 cold air kit done by me
Bullydog E3 economy tuner bone by me
took the 35's off of it and put stock wheels and tires on it done by me
The person I bought it from was/is 19 years old and I guess was trying to get it to smoke or something I dont know. But he did the following to it right before I got it
new injectors with 150 nozzles
raptor fuel pump
I am upset/discouraged because the truck struggles to get 19.2 mpg. The cruise isnt working at this time but should by the end of the day. My vacuum pump is do in today. There is no fuel pressure gage on the truck, is it possible the raptor is pumping to much or is it the 150 injectors. I bay this truck and my driving is 75 percent highway and 25 percent interstate keeping the rpm's under 1900.
My 2007 5.9 does almost 24 and has had nothing done to it.
What do you think?
The truck has the following done to it:
MBRP stainless 4 inch exhaust done by me
AFE stage 2 cold air kit done by me
Bullydog E3 economy tuner bone by me
took the 35's off of it and put stock wheels and tires on it done by me
The person I bought it from was/is 19 years old and I guess was trying to get it to smoke or something I dont know. But he did the following to it right before I got it
new injectors with 150 nozzles
raptor fuel pump
I am upset/discouraged because the truck struggles to get 19.2 mpg. The cruise isnt working at this time but should by the end of the day. My vacuum pump is do in today. There is no fuel pressure gage on the truck, is it possible the raptor is pumping to much or is it the 150 injectors. I bay this truck and my driving is 75 percent highway and 25 percent interstate keeping the rpm's under 1900.
My 2007 5.9 does almost 24 and has had nothing done to it.
What do you think?
10-23-2010, 09:47 AM
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Yeah, thats not bad mileage depending on how fast you are driving. The best numbers will be had around 60-65mph and it drops quickly when you pass that. At 75-80mph my mileage numbers are almost back down to what I get in the city..
I agree that your injectors are also probably a bit much for all your other mods. Your LP is only gonna pump as much fuel as the injection pump needs so I would rule that out....
I agree that your injectors are also probably a bit much for all your other mods. Your LP is only gonna pump as much fuel as the injection pump needs so I would rule that out....
10-23-2010, 01:54 PM
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I just changed the vacuum pump and replaced one of the plastic vacuum tubes under the hood. The cruise now works along with the dash heater controls. I will see this week if it is any better using the cruise control.
I run about 60 mph on the highway and about 68-70 on the interstate which is where the rpm's are about 1900.
I run about 60 mph on the highway and about 68-70 on the interstate which is where the rpm's are about 1900.
10-23-2010, 03:50 PM
#6
FYI... 3rd Gen Trucks don't use vacuum for HVAC controls, all electric... Cruise is it, unless you have an exhaust brake...
19+ is pretty good on MPG, is that hand Calc. or Lie-o-meter??
19+ is pretty good on MPG, is that hand Calc. or Lie-o-meter??
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10-24-2010, 01:40 AM
#8
Thats good MPG...
Thats strange that you have an '03 + that has vacuum controls. I know the 2nd Gens had vacuum controls, but every 3rd Gen I have seen is all electric controls. The vac. hose going into the cowl goes to a vac. tank...
Thats strange that you have an '03 + that has vacuum controls. I know the 2nd Gens had vacuum controls, but every 3rd Gen I have seen is all electric controls. The vac. hose going into the cowl goes to a vac. tank...
10-24-2010, 08:18 AM
#9
There is no G. There is no G. Repeat after me, THERE IS NO G!
"struggles to get 19.2" 
That's good mileage! Is that hwy/city or combined?
Don't worry, your truck is fine. With the truck in my sig I get 16-17combined hand calc'd; only up to 19mpg on pure hwy cruise right under 2k rpm for the entire tank.
That's good mileage! Is that hwy/city or combined?
Don't worry, your truck is fine. With the truck in my sig I get 16-17combined hand calc'd; only up to 19mpg on pure hwy cruise right under 2k rpm for the entire tank.
10-24-2010, 09:00 PM
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10-24-2010, 11:45 PM
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My stock 07 5.9 averages 16 mpg on the liar meter. Yes, 20 on the freeway keeping it under 2000 rpm. Lots of hills here though and I tow a lot.
If your getting 19.5, send me all the stuff your taking off that truck you bought.
If your getting 19.5, send me all the stuff your taking off that truck you bought.
10-25-2010, 12:52 AM
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19.2 is great mileage in my opinion I get 15-18 on the interstate, granted pushing 40" tires isn't helping my fuel economy, I've seen 23 hand calculated once and I had a tail wind and boost stayed between 4-6psi the whole trip
10-26-2010, 05:43 PM
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I hear a lot of people saying they are getting over 24 mpg and I have just found it hard to believe. I was just hoping to get low 20's out of the truck. My commute to work is about 30 miles of 60 mph and 12 at 68 mph.
I now have the cruise fixxed and I am using it now, will see if it is any better. The mileage is not off of the lieometer. The truck is a bare bones work truck without any of that stuff.
I now have the cruise fixxed and I am using it now, will see if it is any better. The mileage is not off of the lieometer. The truck is a bare bones work truck without any of that stuff.
10-27-2010, 04:37 AM
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The flatter the ground you travel the better your mileage will be. Seems like the Florida guys get the best mileage since I don't think there is a hill in the entire state!!! LOL
I had an 03 SO w/ 4:10 gears and it got 24mpg on occasion. I had to drive w/ an egg under the go-pedal and it had to be strictly highway miles with mostly flat ground. My current truck has not been able to match that yet....
I had an 03 SO w/ 4:10 gears and it got 24mpg on occasion. I had to drive w/ an egg under the go-pedal and it had to be strictly highway miles with mostly flat ground. My current truck has not been able to match that yet....
11-01-2010, 06:49 PM
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I'm in the same boat as the original poster.
My truck got 24 mpg empty and 14 mpg towing my 36' 5th wheel after I bought it two years ago. Now I struggle to get 20mpg empty and averaged just 12 mpg over the same 3200 mile loop, same trailer.
A lot of you will say that's not bad mileage but I was consistently getting better until this summer. Only thing I've changed is fluids and filters.
It's not quite pulling the grades without downshifting as well as it used to either. Yet it runs smooth as ever without any codes. My scanguage shows 37.5 MAP pulling grades. Normal boost?
Unless the fuel has changed there's something that's not all it can be on my truck. Do injectors gradually deteriorate?
My truck got 24 mpg empty and 14 mpg towing my 36' 5th wheel after I bought it two years ago. Now I struggle to get 20mpg empty and averaged just 12 mpg over the same 3200 mile loop, same trailer.
A lot of you will say that's not bad mileage but I was consistently getting better until this summer. Only thing I've changed is fluids and filters.
It's not quite pulling the grades without downshifting as well as it used to either. Yet it runs smooth as ever without any codes. My scanguage shows 37.5 MAP pulling grades. Normal boost?
Unless the fuel has changed there's something that's not all it can be on my truck. Do injectors gradually deteriorate?