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Discussion Starter #1
So, here's the background. The truck was bone stock, except for a BHAF and 285 75 R16 tires, coming from Cali to Indiana. I was towing 7500 lbs the whole way over, and averaged 16 mpg during the trip. Got to Indiana, was running about 16-18 in town, 18-20 on the highway, give or take. The only difference between then and now is an AD 150. The day after I put it on, I towed about 2000 lbs from Cleveland to Indiana, and was averaging 12-13 mpgs, and I'm now only getting about 190-256 miles on about 3/4 of a tank. It used to be nothing to hit 150 miles at the first 1/4 of a tank, now, I'm looking at 150 miles at almost a half a tank.
Driving from Cali to Indiana, I was holding pretty steady at about 65-75 mph, coming back from Cleveland, I only was running about 55-60, just because I was trying to figure out the issues with my mileage.
Again, with the new AD 150, I've got a brand new fuel filter, running the 17 lb spring, and I'm sitting right at 17.5 psi at idle, not dropping below 16 at WOT. My buddy has an 02, Edge Comp, 250 injectors, built to the hilt automatic tranny, hx35 with HT3B twin turbo set up, and he's seeing about 19 mpg around town, and he doesn't even drive nice...(not that I would either, with that in my truck...)
Any ideas?:confused013:
 

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Your biggest killer is the body height (wind drag) then the second killer is the oversize tires. (rotational mass and rolling resistance)

Smaller, lighter tires will net you better MPG in the long haul...

http://mopar.cumminsforum.com/tips/cummins/general/better-mpgs/tires.jpg

Believe it or not I lose -3 MPG running the Cooper STT tires over the Michellin LTX. There both the same size but the tread pattern is got a high rolling resistance on the Cooper and the tire is nearly 20 pounds heavier (rotational mass). When I whiched back to the Michellins this spring I gain the +3 MPG right back instantly.

I'm currently planing on switch to 235/85 R16 as my summer tire and shave off anout 10-15 pounds of weight per tire. (rotational mass)

Catch me if you can...
YouTube - Kellogg, ID to Missoula, MT to New Meadows, ID
 

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I would just make sure you have no leaks, other than that its all weather conditions and driving style.
 

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Discussion Starter #4
That's the thing that's baffling me...nothngelse has changed other than the fuel pump between my mileage in Cali and coming from Cali. Tire size was the same, driving style is the same, same actual tires, for that matter....don't know what's going on.
 

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Discussion Starter #6
I'll have to check that out...might be a quick fix to my mileage. Thanks for the tip
 

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Your biggest killer is the body height (wind drag) then the second killer is the oversize tires. (rotational mass and rolling resistance)

Smaller, lighter tires will net you better MPG in the long haul...

http://mopar.cumminsforum.com/tips/cummins/general/better-mpgs/tires.jpg

Believe it or not I lose -3 MPG running the Cooper STT tires over the Michellin LTX. There both the same size but the tread pattern is got a high rolling resistance on the Cooper and the tire is nearly 20 pounds heavier (rotational mass). When I whiched back to the Michellins this spring I gain the +3 MPG right back instantly.

I'm currently planing on switch to 235/85 R16 as my summer tire and shave off anout 10-15 pounds of weight per tire. (rotational mass)

Catch me if you can...
YouTube - Kellogg, ID to Missoula, MT to New Meadows, ID
ummm............

i've always heard that a CTD gains milaege with bigger tires:confused013:

and, i also need to clean up that fuggin AIT thing, the truck has 125k, and is on the stock one as far as i know, and, that one has never been clean:banghead::banghead::banghead:
 

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I doubt cleaning the IAT will help, I just replaced mine and it wasent dirty. check all the connections on the fuel lines you had loose/replaced.good luck.
 

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You are personally coating the highway with fuel from your new spraying system. JMHO
 

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How many miles? Do you think the diaphram inside the pump has torn, from the the new higher fuel pressure?
 

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Similar problem here. When i got my truck, i was getting 15mpg. I threw on taller tires. that put me at 15 mpg. vp was going out so i put on an airdog. It removes the air from the fuel, so surely that would help. So i get it installed and fill the tank to check my gains... 15 mpg. I always heard that a programmer can boost mileage. I found an adrenaline. this time i was excited. fill the tank up and still 15 mpg (on timing only). I started watching my boost and noticed it was extremely low. I found that the wastegate was stuck open. I fixed it and still low boost and 15mpg. Replaced the actuator and finally got boost. Ahh, finally found the problem. Fill the tank and set the trip odometer and... You guessed it. 15 mpg!!! WTF?
 

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Discussion Starter #12 (Edited)
You are personally coating the highway with fuel from your new spraying system. JMHO
not sure where you're going with this...I didn't replace any of the high pressure fuel system parts, just the lift pump (which is the low pressure system pump) so my VP is putting the same amount of fuel to the engine, whatever is left over still returns to the tank via the AD 150. Not spraying anything extra over the highway, especially since my truck does not smoke...AT ALL.:confused013:

"Similar problem here. When i got my truck, i was getting 15mpg. I threw on taller tires. that put me at 15 mpg. vp was going out so i put on an airdog. It removes the air from the fuel, so surely that would help. So i get it installed and fill the tank to check my gains... 15 mpg. I always heard that a programmer can boost mileage. I found an adrenaline. this time i was excited. fill the tank up and still 15 mpg (on timing only). I started watching my boost and noticed it was extremely low. I found that the wastegate was stuck open. I fixed it and still low boost and 15mpg. Replaced the actuator and finally got boost. Ahh, finally found the problem. Fill the tank and set the trip odometer and... You guessed it. 15 mpg!!! WTF? "
I know my boost isn't an issue, since I'm boosting anywhere from 25-30 psi, so no problems with the wastegate.
 

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Similar problem here. When i got my truck, i was getting 15mpg. I threw on taller tires. that put me at 15 mpg. vp was going out so i put on an airdog. It removes the air from the fuel, so surely that would help. So i get it installed and fill the tank to check my gains... 15 mpg. I always heard that a programmer can boost mileage. I found an adrenaline. this time i was excited. fill the tank up and still 15 mpg (on timing only). I started watching my boost and noticed it was extremely low. I found that the wastegate was stuck open. I fixed it and still low boost and 15mpg. Replaced the actuator and finally got boost. Ahh, finally found the problem. Fill the tank and set the trip odometer and... You guessed it. 15 mpg!!! WTF?
It's hard to believe you would have no changes unless you were going balls to the wall frequently.
 

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Discussion Starter #14
How the heck do you put multiple quotes in one post BTW?
 

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Discussion Starter #15
How many miles? Do you think the diaphram inside the pump has torn, from the the new higher fuel pressure?
Doubt it...I was running at about 20 psi for the first few days, until the spring had a chance to settle, then as soon as it did, I watched as the FP dropped to about 17.5, which is right, since I'm running the 17 psi spring in it right now. Plus, it started doing that immediately after I installed it, installed on a Friday, drove to cleveland the next morning. Plus, I'd think I'd either be throwing a code, or my fuel system would be doing something screwy if that happened, which I'm not.:confused013:
 

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Discussion Starter #16
I doubt cleaning the IAT will help, I just replaced mine and it wasent dirty. check all the connections on the fuel lines you had loose/replaced.good luck.
No leaks anywhere, all the connections are dry, every time I look at them. Plus, wouldn't I see or feel air in the system especially under load, if I had a loose connection somewhere?
 

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mileage

ive noticed the same problem after installing my airdog 100 mileage seemed to drop ill clock it to get the exact #


2001 6spd ho airdog 100:confused013:
 

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It's hard to believe you would have no changes unless you were going balls to the wall frequently.

I've run full tanks just babying it and full tanks hot rodding a bit and still pretty much dead on 15 mpg. Weird huh? I did have some vp codes before the airdog though. Maybe its the vp. I don't know.
 

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How the heck do you put multiple quotes in one post BTW?
Ther is a multi quote link right beside quote but I haven't tried that one yet to see what it does.

This might be kindof backwards but you will find QUOTE=dennhop;1497876 In brackets ( Note the username) at the beginning of the message followed by the text with no space between and /QUOTE in brackets at the end of the message (also no space).

If you copy and paste those beginning and ending "codes" with the text you want to quote in between then you will have multiple quotes.

If I want to quote different people I will open another tab in explorer and go to the post I want to quote, click on quote and copy the text to paste into the other post where I am wanting multiple quotes.
 

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Did you figure anything out as to your fuel enonomy yet?
 
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