Author Topic: Fuel Tank Selector Valve - Fuse?  (Read 2867 times)

Offline Mark97213

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Fuel Tank Selector Valve - Fuse?
« on: August 15, 2018, 08:00:30 PM »
1981 Silverado - Does anyone know which fuse in the fuse block is for the Fuel Switching Valve?  All the lettering on the fuse block is gone.

Offline Rapid Roy

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Re: Fuel Tank Selector Valve - Fuse?
« Reply #1 on: August 15, 2018, 08:10:53 PM »
Welcome
1974 Cheyenne 10 LWB 350/TH350/AC/4 BBL Quadrajet
Mopar by Birth
Chevy by Choice

Offline Irish_Alley

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Re: Fuel Tank Selector Valve - Fuse?
« Reply #2 on: August 15, 2018, 08:43:41 PM »
not sure which fuse its under. but most times the issue lays with the switch in the dash. they can be taken apart and cleaned and if it fixes your issue then replace the switch
If you canít tell yourself the truth, who can you tell it to?~Irish_Alley

When you have eliminated the impossible, whatever remains, however improbable, must be the truth ~Sherlock Holmes

Offline bd

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Re: Fuel Tank Selector Valve - Fuse?
« Reply #3 on: August 15, 2018, 08:47:01 PM »
Should be "T" in the attached image.
Rich
It's difficult to know just how much you don't know until you know it.
In other words... if people learn by making mistakes, by now I should know just about everything!!!
87 R10 Silverado Fleetside 355 MPFI 700R4 3.42 Locker (aka Rusty, aka Mater)

Offline Mark97213

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Re: Fuel Tank Selector Valve - Fuse?
« Reply #4 on: August 15, 2018, 09:31:06 PM »
Thank you very much for the diagram.  It will help me with other things.  I will check the switch, good idea.  I'm not getting fuel through a good fuel pump and all lines appear clear.  Is it uncommon for the selector valve to actually go bad and prevent fuel to come up the line?
« Last Edit: August 15, 2018, 10:22:40 PM by Mark97213 »

Offline bd

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Re: Fuel Tank Selector Valve - Fuse?
« Reply #5 on: August 15, 2018, 09:48:26 PM »
Various failures occur, including continuity faults through the selector switch and the motorized switching valve hanging midway between left and right selections.  Other common causes for poor fuel delivery are perforated or kinked fuel lines and sedimentation in the tank(s) plugging the fuel pickup sock(s).  Improper tank venting will also lead to fuel starvation, as will a plugged fuel filter.  If symptoms began immediately after pump replacement, check for misalignment between the fuel pump pushrod and actuating arm.
Rich
It's difficult to know just how much you don't know until you know it.
In other words... if people learn by making mistakes, by now I should know just about everything!!!
87 R10 Silverado Fleetside 355 MPFI 700R4 3.42 Locker (aka Rusty, aka Mater)

Offline Mark97213

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Re: Fuel Tank Selector Valve - Fuse?
« Reply #6 on: August 15, 2018, 10:26:05 PM »
My selector switch literally fell apart as I was removing it to test so I'm thinking that's the best place to start.  All the other suggestions will be the next step.  Thank you.

Offline Irish_Alley

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Re: Fuel Tank Selector Valve - Fuse?
« Reply #7 on: August 15, 2018, 10:37:00 PM »
you might be able to put it back together but
http://forum.73-87chevytrucks.com/smforum/index.php?topic=6537.0
had the same issue on my 91 a couple years ago
If you canít tell yourself the truth, who can you tell it to?~Irish_Alley

When you have eliminated the impossible, whatever remains, however improbable, must be the truth ~Sherlock Holmes

Offline 75gmck25

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Re: Fuel Tank Selector Valve - Fuse?
« Reply #8 on: August 18, 2018, 06:51:10 AM »
On an '81 you should be able to replace the original switch with a standard dual-pole, dual throw toggle switch.  It may look a little ugly, but it works.

- One half of the DPDT switch has the dash gauge wire connected to the center pole, and the top and bottom poles are connected to the two sending unit wires.  It just switches the gauge feed from one tank to the other.
- The other half of the DPDT has 12 volts power on the center pole.  The power wire for the solenoid under the truck is on the top or bottom pole and the other pole is open. In one direction there is power applied to the solenoid, and in the other direction there is no power.  Very simple.

Bruce