My 1983 460 F-350 has only recently started to stall on me when I run it off the rear gas tank. Both gas tanks are completely full of gas, and it runs perfectly fine on the front tank. However, when I switch to the rear tank, I am able to drive for a few hundred yards (just enough to burn the gas in the fuel bowl I'm assuming) before it cuts out. When I flip it back to the front tank fast enough, I can save it from stalling.

It is obvious that gas is not getting to the engine when I am switched to the rear tank. However, I am not sure if the fuel pump for the rear tank is the issue, or I have another problem. For one, I am not sure how the switch operates. Is the system purely mechanical or is it also electrical? If it is purely mechanical, could it be that the switch isn't opening the pathway enough to let gas through to the engine? If it is also electrical, could it be that the switch isn't kicking on the fuel pump because of a broken or lose wire? If the pump is indeed out, how would I replace it? I was told it is inside the gas tank. Do I need to siphon and drop the gas tank to reach it?

Thanks!

 

The switching valve on the frame is both mechanical and electrical. The dash switch sends the power to the proper pump, and also sends a signal to the frame mounted valve to switch the tanks.

The frame mounted valve has a little motor in it. It moves a spool which mechanically swaps the lines. It also has some switch contacts inside so when the motor moves, it switches the fuel gauge sending units and puts the dash gauge on the proper tank.

If your fuel gauge seems to be reading both tanks properly, you may be able to assume the valve is working and it may indeed be a rear tank pump problem.

 

Took it apart and the back fuel pump is working. It is the valve. Looking to buy one now. Ford wants $291.00. I found it on line for $195.00 but still considering "Pick-a-part".

 

do you have the tow package? IF so how did you get it out without cutting the hitch off?

 

The local junkyard will probably have one in the same condition yours is in, only worse with old gas in it. See if this info I have is the same valve as yours. I think Autozone and some other places sell this valve, but it needs a little bit of retro fitting sometimes to get the lines and the wires hooked up. Here's a link to the valve. Fuel Selector Valves on Pollak



Front tank sending unit: Dark blue-yellow
Rear tank sending unit: Yellow-light blue
Fuel gauge: Yellow-white (or white-yellow)

Switch wires:
outer most (closest to edge of plug): Red
second wire in (next to red): Brown-white

Switch on front tank: Red wire
Switch on rear tank: Brown-white wire (i think)

I'll post an update with the final results as soon as I can.



You can use pollak valve. It's the same as FSV2 you find in autozone. Just different package.

The stock wiring is
1-2-3-4-5-6

(1) is not used

The pollak or FSV2 wiring is
A-B-C-D-E-F

(F) is not used

so when you use the new wiring trail make sure to map as follows:
1->F
2->E (Main Tank)
3->D (Aux Tank)
4->C (aux tank sender)
5->B (fuel gauge)
6->A (main tank sender)

Hope this helps!




http://pollak.thomasnet.com/viewitem...lve?&forward=1


Using the Pollak wiring labels power on E should select the front tank, power on D should select the rear tank.

D and E both supply positive and negative power to the FSV.

So when E is positive, D should be ground.
Flip the switch to the rear tank, D should be positive and E should be ground.

When the valve is changing tanks, the last thing it does is make the fuel gauge connection on the selected tank.

Did the gauges work correctly before you changed the valve?

Position A,B and C are the only connections that have anything to do with the fuel gauge.
Position A and C should be going to the tank senders with B going to the gauge.
Also not sure about how the newer ones are wired, but I have ground wires from the senders that are tied together near the FSV on mine.
Do you have any disconnected grounds?


so.for others,i may as well state everything to help you get it right.
first.this valve uses 6 ports.the engine to valve is obvious.connect the main tank (in my case the front) to the L port of the valve.
connect the R for your aux tank (in my case the rear.)
(i had this right)

pin 1 is NOT used.not by ford nor this valve.
you will see the blank spot in your old harness.
(i had this right)

Yellow/Blue Stripe = A
Yellow/White Stripe = B
Blue/White Stripe = C
Red = D
Black/White Stripe = E
None = F
(i had this wrong.like stated here,worked perfect for my '93)

feels good to know i saved a boat load on a new FSV,and wiring it up is quite easy actually when you pay attention to the old wiring harness.this should help those like me,who just want to match up the colors and keep it simple.


i should also state to help future researchers,a simple tip,despite your colors of wires,
just cut off your stock connector,then look at it.notice the blank spot in the connector(where there is no wire to connect.)
well,right next to this side(the first wire next to it) is your "E".then follow your stock colors on your connector,over.so your next color beside "E" will be your "D" then c,b,a as you go across to the other side.
so when you cut your stock connector off,leave enough tails on your wires to be able to see each color so you can match it up.
this will make sense when your doing it.very simple really this way.

also note,when you try to bolt it back to the frame rail,the spacing is slightly off.you can start each bolt and it will catch and tighten.however,it will kink the top rear fuel lines.
she's stalling out on me when i select the rear tank,and the line pumps clean from the front tank.(that would REALLY suck for you guys who haven't done the electric pump conversion yet.as you would have to crank,and crank to prime the system again!!! so make sure you don't kink off the line.)
so i think i can just use one bolt.i'l use the top bolt in FSV and the bottom bolt hole in the frame.this should hold it plenty and provide more room so the lines don't kink.( but if your worried,and or want to really do it "right",you could drill another hole in the frame down lower,so you have both bolts again.i think the one with rust up and hold forever just fine,the fuel lines hold it all there too,so its not like it could fall off or anything.)

also note,this valve,just uses standard hose connections.not the stock fuel connections.
all you need to do,is cut the end off the ends going into the FSV,and strip back the outer hose.you can now slide your rubber hose right on the stock fuel connector lines going into the tanks!just secure with standard hose clamps.its all low pressure,so no worries.

 

It did not come with the tow package. I had the hitch installed myself.

Franklin, thanks for the info. I had tried Kragen's but they did not have the switch. I will check these out.

Thanks

 

Just for the record, the valve you should get from autozone is FSV2K, or just make sure if available you get the 6 port valve with the pigtail, don't get home and realize you forgot it. The nice part about FSV2K is it is the same price as FSV2, if not they charge you and extra 19.99 for the pigtail if you buy them separately.


Cheers,
Devin

 

I took bolts off. Impact.. most broke though I figured if they are that rusty they need replaced

 

my front tank doing same