Fuel Mileage

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Dec 12, 2009 | 07:48 AM

HD07Redhead

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Fuel Mileage

Good morning, I just bought a used 1993 F150 XLT w/a 4.9L engine & a 5 speed. The truck has 233xxx miles but looks runs & drives out great. My problem is that I filled both tanks upon purchase and got ~360 miles out of the rear tank, then switched to the front tank and only got ~150 miles out of 3/4 of the tank. I know that the front tank holds ~18 gallons and the rear ~19. So what's the deal with the low mileage out of the front tank? Also, I experienced gas overflowing from the rear tank out of the filler neck twice for a total of about a gallon of gas wasted. Then it didn't do it again. Any info would be greatly appreciated.

Thanks

Dec 12, 2009 | 09:56 AM

brett12396f150

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My guess would be your front tank is filling the rear. (when something goes it does this) Someone with more experience should know :P

Dec 12, 2009 | 10:10 AM

ccecilm2

Mountain Pass

Joined: Jun 2006

Posts: 230

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It is probably the typical check valve problem causing fuel cross flow Read this thread:
https://www.ford-trucks.com/forums/3...w-problem.html

I never did have the problem but have seen many threads about it in this forum.

Dec 12, 2009 | 10:12 AM

Conanski

FTE Legend

Joined: Jun 2006

Posts: 31,930

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From: Ottawa, Ontario

Yes you have the fuel transfer problem so you will need to drop at least one tank and change the FDM, in your case I think the problem is with the front tank.

Dec 12, 2009 | 10:14 AM

BCHauler

Fleet Mechanic

Joined: Apr 2008

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From: Vancouver BC Canada

Very common problem. The check valve in the rear tank is allowing the return fuel to flow into the rear tank when the front tank is being pumped. I believe you have to replace the rear fdm.

edit: nevermind what I just said. Listen to Paul, he knows what he's talking about.

Dec 12, 2009 | 11:46 AM

Conanski

FTE Legend

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Posts: 31,930

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From: Ottawa, Ontario

Quote:

Originally Posted by BCHauler

edit: nevermind what I just said. Listen to Paul, he knows what he's talking about.

Ha!!... well I made a guesstimate based on how the OP described the problem and I could have intrepreted it wrong. I guess we both have a 50/50 chance of being right.

Dec 13, 2009 | 07:29 AM

ccecilm2

Mountain Pass

Joined: Jun 2006

Posts: 230

Likes: 11

NHTSA documentation:
Go here [ http://www-odi.nhtsa.dot.gov/recalls/recallsearch.cfm ] and search for campaign # 93V125000

You may find something from Ford at the link below but I doubt it. You will need your VIN number.
Recall Information - Ford