Fuel tanks running out

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Obwonkonobe

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RustyPile

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Ooh, I understand a bit better. Ive seen those valves, have no idea how they work. I have what i think is an earlier style, just one wire

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Hmmm. I'm not familiar with that single wire type.. Could be an after market installation.. Maybe someone else can chime in here..
 

78C10BigTen

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Ooh, I understand a bit better. Ive seen those valves, have no idea how they work. I have what i think is an earlier style, just one wire

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Thats what my truck has
 

bucket

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In addition to leaky fuel lines, you've got the selector valve wired wrong.. It's not a solenoid that needs constant power.. The selector valve is actually a spool valve. The "electric part" is an ungrounded DC motor that moves the spool valve. The switch is wired in such a way that polarity is reversed back and forth to make motor change rotation direction. Once the motor has moved the spool valve, voltage is not needed to "hold" the valve. Momentary voltage application is all that's needed. The factory control switch in the dash has 2 parts.. One part of the switch selects the proper tank gauge sending unit.. The other parts applies the voltage momentarily to the selector valve.. The wiring for dual tanks is complex but not difficult to add/construct once you understand how the system works..

Hmmm. I'm not familiar with that single wire type.. Could be an after market installation.. Maybe someone else can chime in here..

The older trucks have a simple solenoid valve with a 12v wire and it self grounds to the frame from what I remember. It's been a while since I had mine apart. Without power to the solenoid, it pulls fuel from the right side. When the dash switch (just a basic rocker) is switched to left, it sends the 12v to the solenoid and it pulls fuel from the left.

I like to use the left tank as the primary tank. It keeps the solenoid active and if it ever quits working for some reason, it will just divert to the right tank with fuel still in it.
 

Obwonkonobe

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The older trucks have a simple solenoid valve with a 12v wire and it self grounds to the frame from what I remember. It's been a while since I had mine apart. Without power to the solenoid, it pulls fuel from the right side. When the dash switch (just a basic rocker) is switched to left, it sends the 12v to the solenoid and it pulls fuel from the left.

I like to use the left tank as the primary tank. It keeps the solenoid active and if it ever quits working for some reason, it will just divert to the right tank with fuel still in it.

That's how I need to set mine up, good concept
 

RustyPile

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The older trucks have a simple solenoid valve with a 12v wire and it self grounds to the frame from what I remember. It's been a while since I had mine apart. Without power to the solenoid, it pulls fuel from the right side. When the dash switch (just a basic rocker) is switched to left, it sends the 12v to the solenoid and it pulls fuel from the left.

I like to use the left tank as the primary tank. It keeps the solenoid active and if it ever quits working for some reason, it will just divert to the right tank with fuel still in it.
What's the arrangement for switching the sending unit in the tanks -- a separate spdt switch.. Seems primitive... No wonder GM went to the motorized valve.. Everything gets switched with a single switch, even the vent system... The vapor canister on my truck is a "dual unit" and it gets switched in the process...
 

Obwonkonobe

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What's the arrangement for switching the sending unit in the tanks -- a separate spdt switch.. Seems primitive... No wonder GM went to the motorized valve.. Everything gets switched with a single switch, even the vent system... The vapor canister on my truck is a "dual unit" and it gets switched in the process...

No its a dpdt, all in one, I just run the vents into a t
 

bucket

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What's the arrangement for switching the sending unit in the tanks -- a separate spdt switch.. Seems primitive... No wonder GM went to the motorized valve.. Everything gets switched with a single switch, even the vent system... The vapor canister on my truck is a "dual unit" and it gets switched in the process...


The dash switch controls the solenoid and switches the senders to the gauge.
 

RustyPile

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The dash switch controls the solenoid and switches the senders to the gauge.
gotcha.. Must be a helleva solenoid to handle 100% duty cycle for hours and hours...
 

bucket

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gotcha.. Must be a helleva solenoid to handle 100% duty cycle for hours and hours...

Couldn't tell ya, but it's roughly the size of a door lock actuator.
 

RustyPile

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Couldn't tell ya, but it's roughly the size of a door lock actuator.
I didn't necessarily refer to it's size.. Just it's ruggedness..
 

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