Fuel switch
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Freshman User
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Fuel switch
I have a 1985 f250 with the 460 in it it seems to me when I go to switch the tank over from the rear tank to the front tank it still pumps out of the rear anyone else have this problem and know how to fix it?
pedant
Joined: Jan 2008
Posts: 23,576
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From: EXTREME southwest CT
I'm assuming you have Hot Fuel Handling (electric in tank pumps).
Have you checked your fuses?
With this system default is the rear tank.
There are two relays. One is for pump power, the other is the selector relay which selects the front tank when power is applied and the relay closes.
Maybe this relay has failed or maybe it is not getting power from the switch on the dash.
You could remove it and test it or test for power at the socket with the front tank selected and the key on.
Have you checked your fuses?
With this system default is the rear tank.
There are two relays. One is for pump power, the other is the selector relay which selects the front tank when power is applied and the relay closes.
Maybe this relay has failed or maybe it is not getting power from the switch on the dash.
You could remove it and test it or test for power at the socket with the front tank selected and the key on.
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Joined: Jan 2001
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From: Virginia
Usually when it pulls from one tank and returns to the other tank, the switching valve on the frame is bad. It's a valve with a little motor that moves the spool for the valve, and also has contacts in it to switch the sending units going to the fuel gauge.
Ford wants a lot of money for an original one. The parts stores sell a universal valve that works the same, but it's not plug and play, you have to do some modifications to the wiring plug and the fuel lines. Look for "pollack valve" on the internet.
Ford wants a lot of money for an original one. The parts stores sell a universal valve that works the same, but it's not plug and play, you have to do some modifications to the wiring plug and the fuel lines. Look for "pollack valve" on the internet.
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Yes I do I do have an electric fuel pump that goes it the tank
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pedant
Joined: Jan 2008
Posts: 23,576
Likes: 40
From: EXTREME southwest CT
I edited my post above.
The selector relay gets its power from a blue fusible link attached to the + terminal of the starter relay.
See if it is intact and not blistered.
The selector relay gets its power from a blue fusible link attached to the + terminal of the starter relay.
See if it is intact and not blistered.
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From: Virginia
Keep checking everything out, but you may find it's still the valve. They are notorious for not working after years of use. Mine quit on me and I just run the front tank now and took the valve out.
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Okay thanks, I'll be looking around
pedant
Joined: Jan 2008
Posts: 23,576
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From: EXTREME southwest CT
There should be a pair of relays near the drivers hood hinge.
The pump relay is triggered by the oil pressure switch and then the selector relay changes from rear to front tank.
As I said, default is rear, so if the selector relay is unpowered or dead you will only be able to draw from the rear.
The pump relay is triggered by the oil pressure switch and then the selector relay changes from rear to front tank.
As I said, default is rear, so if the selector relay is unpowered or dead you will only be able to draw from the rear.
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Freshman User
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There should be a pair of relays near the drivers hood hinge.
The pump relay is triggered by the oil pressure switch and then the selector relay changes from rear to front tank.
As I said, default is rear, so if the selector relay is unpowered or dead you will only be able to draw from the rear.
The pump relay is triggered by the oil pressure switch and then the selector relay changes from rear to front tank.
As I said, default is rear, so if the selector relay is unpowered or dead you will only be able to draw from the rear.
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I don't want to hijack this thread, but how do you figure out if the truck is actually swapping tanks.
I have an 86 F250. Previous owner told me that he never used the rear tank, but he put 5 gallons in it to test it. When I swap the lever to pump from the rear tank, the fuel gauge goes to empty but the truck keeps running.
I'm just trying to figure if it's actually pumping from the rear tank or if it's still pulling from the front.
I have an 86 F250. Previous owner told me that he never used the rear tank, but he put 5 gallons in it to test it. When I swap the lever to pump from the rear tank, the fuel gauge goes to empty but the truck keeps running.
I'm just trying to figure if it's actually pumping from the rear tank or if it's still pulling from the front.
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Joined: Jan 2001
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From: Virginia
You can find a quiet place, and with the engine off turn the key on. Then switch the valve back and forth. When mine was working I could hear a "thump" under the truck each time I switched the dash switch.