Fuel tank selector

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May 24, 2003 | 10:37 PM

dan_da_mick

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Joined: Feb 2002

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Fuel tank selector

Has anyone had the fuel tank selector valve go out on their truck?

I have an '87 F150 4x4 with dual tanks. It won't run off of the rear tank. I pulled the supply line from the rear tank off of the selector valve. With the truck running, I switched over to the rear tank and gas gushes out, so it seems the pump works, although I haven't taken a fuel pressure measurement.

It seems like a simple enough device that wouldn't be prone to failure, but I can't think what else it would be.

May 25, 2003 | 11:18 PM

steve83

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Joined: Nov 2002

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From: Memphis, TN

Fuel tank selector

There are several threads about that valve, and at least one includes general instructions on disassembly & repair. It might be in the fuel forum.

Jun 12, 2003 | 01:27 PM

rugerj

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Joined: Feb 2003

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Fuel tank selector

I am having similar problems and have read many many posts but am unable to find this post demostarting how to remove/repair the slector valve. Can someone out there point me in the right direction? Thanks.

Jun 12, 2003 | 02:08 PM

jbalestri

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Joined: Dec 2002

Posts: 1,297

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From: Billings MT

Fuel tank selector

Make sure it is the valve, and not the switch first.

Jun 13, 2003 | 01:30 AM

ludis

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Joined: Aug 2001

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Fuel tank selector

Make sure you don't have one of the defective valves. The "fixed" part number starts with F1U. Several years worth of trucks were recalled (I think, or perhaps just a TSB) to replace defective valves.

Jun 13, 2003 | 06:47 AM

rugerj

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Joined: Feb 2003

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Fuel tank selector

I will checkout the part number first, thanks for the advice. I am thinking it may be this piece because when I switch tanks the fuel gauge reads full (I have just topped off the tank) but it continues to pull gas from the front tank. If not I will start diagnosing the both the low pressure tank pumps first and work my way forward. Another question. Would the high pressure pump be the only reason why I have to crank the engine for about 5-7 seconds first thing in the morning to get it started. I think that the fuel pressure is droppping overnight and the fuel is bleeding back towards the tank. It starts fine for the rest of the day. I know i do not have a physical fuel leak anywhere because I don't see any spots on my garage floor in the morning.

Jun 13, 2003 | 10:10 PM

steve83

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Joined: Nov 2002

Posts: 9,987

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From: Memphis, TN

Fuel tank selector

Since the truck runs on the wrong tank, it sounds like your switch (in the dash) may be bad & not actually switching the pump power. It could be that the hi-pressure pump is pulling fuel from the wrong one because the selector valve (on the frame rail) isn't switching, but most people's trucks stall when that happens. Verify WHICH lo-pres pump is getting power when the dash switch is set for the rear tank, and try tapping on the selector valve to get it to change over. Marvel Mystery Oil (MMO) in the gas may loosen it up.