Fuel filter change
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Junior User
Joined: Mar 2009
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From: Spencerport NY
Fuel filter change
I bought two fuel filters from ebay and changed mine for the first time.I have an 1999 F350 7.3 Since I changed the filter my milage has gone down.Can the fuel filters from ebay cause this? I only have 29,000 miles on this truck and use it the same every year.I pull a 36' 5th wheel from May thru Sept.I was getting 13mpg,now I get 10.5mpg.
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Ron
Early 99 F350 7.3 4:10 gear
Used only in the summer 29,000 miles
__________________________________________________ _________
Ron
Early 99 F350 7.3 4:10 gear
Used only in the summer 29,000 miles
Post Fiend
Joined: Feb 2007
Posts: 14,541
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From: Dallas-Ft. Worth
When's the last time you towed? 10.5 doesn't seen THAT bad pulling a 36' fiver!
EDIT: But it could be something else, like a boost like killing your mileage. Check all your boots to make sure they're tight, and look at your up-pipes. Should be no soot visible there. You can make a boost leak tester easily out of an air hose nipple, 1/4-18 NPT tap, and a 3" PVC cap. Here's what mine looks like:
EDIT: But it could be something else, like a boost like killing your mileage. Check all your boots to make sure they're tight, and look at your up-pipes. Should be no soot visible there. You can make a boost leak tester easily out of an air hose nipple, 1/4-18 NPT tap, and a 3" PVC cap. Here's what mine looks like:
Senior User
Joined: Dec 2007
Posts: 384
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From: North wales , PA and nj
checked the o-ring. one thing as a mechanic that ive always been told is never use the old one. other than that make sure the filter is in right. other than that there is nothing else that should cause fuel issues from changing a filter
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Junior User
Joined: Mar 2009
Posts: 56
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From: Spencerport NY
The filter is not leaking and yes I used the same o-ring.Their is no fuel anywere on the ground or engine.The last time I got 13mpg was last year.This year after the filter change it's down to 10.5mpg.This year I started using an additive(deisel clean gray bottle)after reading this web site.8oz.per tank(38.5gal tank).
__________________________________________________ _______________________________
Ron
Early 99 F350 7.3 4:10 gear
Used only in the summer 29,000 miles
__________________________________________________ _______________________________
Ron
Early 99 F350 7.3 4:10 gear
Used only in the summer 29,000 miles
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Posting Guru
Joined: Jul 2006
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From: Jonestown PA
Maybe the new diesel fuel their making just isn't the best for milage. IDK..... Anyways, nice looking rig with low miles you got there.
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Post Fiend
Joined: Feb 2007
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From: Dallas-Ft. Worth
So is this hand calculated? And are you filling up to the rim every time? Also, you should be using one ounce of DK per 3 gallons of fuel. I use 10 ounces in my 30 gallon tank. You should be using 13 ounces at a minimum. My "29" gallon tank actually holds 34+. Your "38" gallon tank holds somewhere around 43ish. If you haven't done the Harpoon mod, it's a major PITA to fill it all the way every time. And 38 to 43 gallons leaves a lot of slop for mileage calculations.
Just some more ideas that come to mind...
Just some more ideas that come to mind...
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Junior User
Joined: Mar 2009
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From: Spencerport NY
I have been checking my milage the same way for years.This is the first year it has been this low.The only thing different this year is changing the trans.fluid,rear end fluid and anti-freeze.Everything else on this truck are from the day I picked it up(except tires).They were cracking last year.I put on the same size as I took off. I still have the stock CPS.
__________________________________________________ _________________
Ron
Early 99 F350 7.3 4:10 gear
Used only in the summer 29,000 miles
__________________________________________________ _________________
Ron
Early 99 F350 7.3 4:10 gear
Used only in the summer 29,000 miles
Posting Guru
Joined: Jul 2006
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From: Jonestown PA
same size tire but was it the same make? I know differnt makes of the same size are differnt weight, more rotating mass. Not sure if that could be anything to think about. Just a thought....
More Turbo
Joined: Mar 2007
Posts: 636
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From: La Mesa, Ca.
Fresh tires can have a big effect on mileage. The newer rubber will have more "squish" that give you that "smooth" ride. The tire will get harder with time and get you you back the mileage you once had. You might try raising the air pressure up and see if you mileage comes back.
Nick
Nick
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Junior User
Joined: Mar 2009
Posts: 56
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From: Spencerport NY
The tires that came on the truck in June of 98 are no longer made,but I did buy Firestone again.Firestone came on it.I run 70lbs in the front and 55lbs in the back(DRW).That is what is on the driver door.
I didn't know new tires could cause milage drop.Thanks for that Nick.If that is the reason ,then I will have bad milage for a long time.The last tires lasted almost 11 years.I only put on about 2500 miles a year.
__________________________________________________ ____________________________________
Ron
Early 99 F350 7.3 4:10 gear
Used only in the summer 29,000 miles
I didn't know new tires could cause milage drop.Thanks for that Nick.If that is the reason ,then I will have bad milage for a long time.The last tires lasted almost 11 years.I only put on about 2500 miles a year.
__________________________________________________ ____________________________________
Ron
Early 99 F350 7.3 4:10 gear
Used only in the summer 29,000 miles
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