gas cap......

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Feb 26, 2010 | 10:30 PM

traxx808

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From: on the garage floor. lol!

gas cap......

i bought 2 locking gas caps cause the last few weeks someone has been stealing gas out of the autos at night around the neighborhood and who ever it is takes a lot of it too. today after work i drove the truck home and started to unscrew the gas cap from the rear tank and in the process of doing so gas started to come out like it was under high pressure so i started to screw it back on to stop it from coming out. i was shocked to say the least to see that happening. i almost felt like i had to pick up my lower jaw off the ground. i have never seen that before. i do have duel tanks on my 94 f150. does it have something to do with the fuel return lines or could it be from over filling the gas tank after it clicks off the 1st or 2nd time. i need help on this cause i don't want it to explode in my face the next time and my girl friend uses this truck too........thanks in advance guys.....................

Feb 27, 2010 | 06:49 AM

TexasGuy001

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It sounds like you have the crossflow problem associated with dual tanks. The 80-86 and 87-91 trucks are more prone to this problem. Some of the 92-96 trucks have had it as well. From what I have read, Ford supposedly remedied this problem sometime around 94. My friend had this problem with his 96 F150. I wouldn't have thought it would have that issue. Do a search for crossflow, cross flow, tank overflow etc. There are several threads on this topic.

Feb 27, 2010 | 08:03 AM

EPNCSU2006

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Joined: Nov 2002

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From: Concord, NC

I'd say the newer trucks are the most prone to this problem, with '90-'93 or so trucks actually being recalled for this issue. Cross flow looks to be most likely on the trucks with the shuttle-valve setup in the tanks.

If the fuel is crossing from the front tank to the rear tank, the rear tank shuttle valve assembly is not working properly and should be replaced.

Feb 27, 2010 | 11:11 AM

traxx808

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From: on the garage floor. lol!

thanks for the feed back guys.......epncsu2006 just want to know what is a rear tank shuttle valve assembly. is it on the inside or outside of the tank. what does it look like or do i change the rear fuel pump assembly cause that is the tank thats over flowing with gas........thanks.............

Feb 27, 2010 | 01:00 PM

subford

Fleet Owner

Joined: Aug 2005

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From: Easton,Ks

The shuttle and check valves are inside the Fuel Delivery Assembly (FDM) inside the tank.

Feb 27, 2010 | 03:40 PM

traxx808

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From: on the garage floor. lol!

hey guys i wanted to run something past you all. i saw a can of berrymans b-12 chemtool fuel treatment. would it fix the problem or would it be a temporary fix at best and i should just buy a new fuel assembly. hey subford thanks for the pic.

Feb 28, 2010 | 12:08 PM

EPNCSU2006

Lead Driver

Joined: Nov 2002

Posts: 9,557

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From: Concord, NC

It's not likely that a fuel additive will fix the problem, unless it is the result of some kind of build-up in the check valve. This is usually not the case if both tanks are used regularly.