- Aug 30, 2001
- 1,524
- 0
This was posted in a diesel forum as well:
My question is this, according to reading posts about fuel consumption with 315/75/16 tires, my fuel milage is lacking. The truck is a 2001 4x4 CC PSD with 3.73 and 2" add-a-leafs and small blocks in the rear.
My fuel milage when the truck was new was 15 to 17 mpg empty and 13 to 15 mpg pulling a 6x12 enclosed trailer with dirtbikes in it. According to some reading, I wasn't getting terrific milage, but wasn't horribly dissatisfied either.
About 15000 miles ago I installed a DiabloSport Chip labeled 4 bank X14. It was programmed with the lower power setting (50 -60 hp?). The power increase was noticed immediately, but I was hoping to gain some fuel milage out of the upgrade as well. With the new found power, my right foot may have gotten "heavier" so I didn't realize any MPG increase. In fact, the MPG was down 1 to 2 MPG. No big deal I thought. I just put on the 285/75/16 tires and the 2 inch lift. Maybe that was the cause.
Well, after a while, the milage decreased another 1 to 2 MPG. Attributed that to wintertime etc... even though I live in Louisiana. Then I installed the 315/75/16 tires and saw another 1 MPG drop.
One thing to note was that after installing the chip, occasionally when accellerating/merging into traffic or sometime hard accelleration with a trailer, the tranny or truck would "shudder" or try to shift 1 or 2 times more when shifting up to high. I have done some reading today and wonder if this is the compressor surge or flutter that I have just read about. It only does it under load or acceleration and shifting to high. (?) Note that my trailer loads with this vehicle have never been more than the 6x12 enclosed trailer with 1500 or lbs. of bikes and gear.
Fuel milage was now down to about 11 to 12 mpg city/hwy and 10 to 11 with the light towing that I do. I know this is more truck than I need now that I sold my 76 Bronco and no longer need this much truck, but I really do like it.
Anyway, last week, I went to Reno, by way of KC, MO and through the mountains to Denver, Wy, Ut and finally Nv. Fuel milage with 4 bikes and gear was worst of 8 and best of 10 MPG. Figure in larger tires at approx. 10.6% and figure best was actually 11 mpg.
So, today, for a check, I pull out the chip and made a 200 mile round trip and checked milage. The first 100 miles was without the trailer, and correcting for tire size, without the trailer on the way up was almost 14 mpg. Picked up the trailer with one bike and brought it back from the riding area where I left it at our clubhouse 2 days ago and returned and checked the milage correcting for tire size was 10 MPG.
I called the dealer that I bought the chip from, told him of my experince with the shifting and the fuel milage. He suggested that it might be a problem with my torque converter that was magnified by the increased power provided by the chip.
Does this sound reasonable, do my MPG figure sound reasonable or not with the way the truck is currently equipped? What should I check, or should I take it to the dealer for inspection. The shop/owner where I bought the chip said he could make sure any evidence of the chip was removed before taking it in to avoid any potential warranty problems as well.
Now that I have written a small novel, I am hoping the someone with some expertise here can provide some input and info because I really don't want to sell my truck and feel that I should be doing better milage wise. I can't see myself buying one of the other two brands, so please any other brand loyal guys, save you breath in that category. This is minor to the other problems I have had with other brands.
Thanks in advance for any assistance you can provide.
Randy
My question is this, according to reading posts about fuel consumption with 315/75/16 tires, my fuel milage is lacking. The truck is a 2001 4x4 CC PSD with 3.73 and 2" add-a-leafs and small blocks in the rear.
My fuel milage when the truck was new was 15 to 17 mpg empty and 13 to 15 mpg pulling a 6x12 enclosed trailer with dirtbikes in it. According to some reading, I wasn't getting terrific milage, but wasn't horribly dissatisfied either.
About 15000 miles ago I installed a DiabloSport Chip labeled 4 bank X14. It was programmed with the lower power setting (50 -60 hp?). The power increase was noticed immediately, but I was hoping to gain some fuel milage out of the upgrade as well. With the new found power, my right foot may have gotten "heavier" so I didn't realize any MPG increase. In fact, the MPG was down 1 to 2 MPG. No big deal I thought. I just put on the 285/75/16 tires and the 2 inch lift. Maybe that was the cause.
Well, after a while, the milage decreased another 1 to 2 MPG. Attributed that to wintertime etc... even though I live in Louisiana. Then I installed the 315/75/16 tires and saw another 1 MPG drop.
One thing to note was that after installing the chip, occasionally when accellerating/merging into traffic or sometime hard accelleration with a trailer, the tranny or truck would "shudder" or try to shift 1 or 2 times more when shifting up to high. I have done some reading today and wonder if this is the compressor surge or flutter that I have just read about. It only does it under load or acceleration and shifting to high. (?) Note that my trailer loads with this vehicle have never been more than the 6x12 enclosed trailer with 1500 or lbs. of bikes and gear.
Fuel milage was now down to about 11 to 12 mpg city/hwy and 10 to 11 with the light towing that I do. I know this is more truck than I need now that I sold my 76 Bronco and no longer need this much truck, but I really do like it.
Anyway, last week, I went to Reno, by way of KC, MO and through the mountains to Denver, Wy, Ut and finally Nv. Fuel milage with 4 bikes and gear was worst of 8 and best of 10 MPG. Figure in larger tires at approx. 10.6% and figure best was actually 11 mpg.
So, today, for a check, I pull out the chip and made a 200 mile round trip and checked milage. The first 100 miles was without the trailer, and correcting for tire size, without the trailer on the way up was almost 14 mpg. Picked up the trailer with one bike and brought it back from the riding area where I left it at our clubhouse 2 days ago and returned and checked the milage correcting for tire size was 10 MPG.
I called the dealer that I bought the chip from, told him of my experince with the shifting and the fuel milage. He suggested that it might be a problem with my torque converter that was magnified by the increased power provided by the chip.
Does this sound reasonable, do my MPG figure sound reasonable or not with the way the truck is currently equipped? What should I check, or should I take it to the dealer for inspection. The shop/owner where I bought the chip said he could make sure any evidence of the chip was removed before taking it in to avoid any potential warranty problems as well.
Now that I have written a small novel, I am hoping the someone with some expertise here can provide some input and info because I really don't want to sell my truck and feel that I should be doing better milage wise. I can't see myself buying one of the other two brands, so please any other brand loyal guys, save you breath in that category. This is minor to the other problems I have had with other brands.
Thanks in advance for any assistance you can provide.
Randy