Mileage Dropping
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From: Houston, Texas
Mileage Dropping
I recently noticed that the mileage on my X has REALLY started to drop. I normally got atleast or between 700 and 725 miles out of one tank. (that's combined city and highway driving) Now I'm lucky if I can get 650 much less for 625. This is all running "Diesel Kleen" the white bottle. I do about average 50 mph in the city and always 65 on the freeway. I rarely so 70 unless I'm feeling "adventureous". I took out my K&N drop in because I found a small amount of dust and freaked. So I put back in my paper filter and have been with that ever since. I think that has alot to do with it, but I've also read that lower fuel mileage could also mean that something is wrong or going wrong. I don't know what, if anything, could be wrong.
What could be killing my mileage like this? Better yet, what can I do to help it?
What could be killing my mileage like this? Better yet, what can I do to help it?
Last edited by Toreador_Diesel; Mar 24, 2004 at 08:23 AM.
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From: Houston, Texas
Originally posted by TN Hillbilly
Have you checked your tire pressure? Made about a 2 mpg difference when I had the inflated to 55/70. Dips**t dealer had dropped them down to like 40/45 when they did my first oil change.
Have you checked your tire pressure? Made about a 2 mpg difference when I had the inflated to 55/70. Dips**t dealer had dropped them down to like 40/45 when they did my first oil change.
My tires are inflated to 65 lbs. all around becuase I have load range "D" tires. But even if I do drop the pressure a bit, how or better yet, why does it make a difference?
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Properly inflated tires wear correctly, of course. It doesn't talke as much energy to rotate an inflated tire compared to a deflated tire, physics. About as good as I can explain it, but it really did make a difference in mine, but mine were underinflated. If you are at 65 it wouldn't have an major effect on yours I don't believe.
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From: Denton,TX
Originally posted by TN Hillbilly
Properly inflated tires wear correctly, of course. It doesn't talke as much energy to rotate an inflated tire compared to a deflated tire, physics. About as good as I can explain it, but it really did make a difference in mine, but mine were underinflated. If you are at 65 it wouldn't have an major effect on yours I don't believe.
Properly inflated tires wear correctly, of course. It doesn't talke as much energy to rotate an inflated tire compared to a deflated tire, physics. About as good as I can explain it, but it really did make a difference in mine, but mine were underinflated. If you are at 65 it wouldn't have an major effect on yours I don't believe.
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True john, why I said properly inflated tires. If over inflated they will wear in the middle, underinflated on the outer portion. I realized to start checking mine regulary due to what dealer did and dropped my mileage, plus would cause more wear on outside of tires.
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From: Houston, Texas
Originally posted by johnsdiesel
Your logic regarding mileage and tire pressure is correct, but if you run a tire at the max pressure without load it will wear unevenly. I always run mine at a lower pressure when I'm not hauling/towing. It sacrifices mileage a little, but the tires wear evenly and the ride is smoother.
Your logic regarding mileage and tire pressure is correct, but if you run a tire at the max pressure without load it will wear unevenly. I always run mine at a lower pressure when I'm not hauling/towing. It sacrifices mileage a little, but the tires wear evenly and the ride is smoother.
I don't see too many F-250/350 or Excursions running these tires. That and the fact that they are load range "D" tires, is the only reason why they are at max load. The X, after all, is a very heavy vehicle. But if I put 55 up front and leave 65 in the back, do you think that will make much of a difference?
I don't want the tires to wear unevenly and I don't want the to blow because they were underinflated.
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From: IOWA
I would leave them all at 65, especially in the front. The majority of your weight on a diesel is up front from the motor. It's hard to judge where to put them at. You might just have to play with it and run it with different pressures and see how it performs. Lower pressure you will have a smoother ride and tend to get better traction, higher pressure the ride will be a little harder, but the tires will roll easier and give a little better mileage. Good luck.
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From: Houston, Texas
Although my fuel filer does need changing as 78fordman suggested, something just occured to me. Do you think the "winter blend" of diesel has anything to do with it? Here in Texas I don't think fuel gelling is a much of a serious problem. Or is the "winter blend" diesel shipped to all over Texas anyhow?
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From: IOWA
I don't know if you have winterblended fuels in Texas, I know here in Iowa they will say say on the pump when they have the winter blend. But yes, the winterblend will decrease your fuel mileage. It is a mix of #1 and #2 diesel. #2 is what is normally ran, and the #1 is added to help keep the fuel from gelling as soon at lower temperatures. The drawback is that it has #1 has fewer BTUs than the #2 resulting in poorer performance. Hopefully that will answer your question.
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From: Butler, PA
About the Load Range D Tires on the X
There is talk of a tire recall for X's with Load range D tires, made in Quebec, Canada. I also believe somewhere else but I am unsure. Check the X forum if you have not seen it already. The dealer should be replacing the tire (if in the recall) with a load range E tire. Which should have been on there in the first place, hence the recall.
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From: Houston, Texas
Originally Posted by bigdieseldav
geez, what size tank do you have???? i'm lucky to get450miles out of my truck on one 29 gallon tank full?
