fuel tank selector switch
03-07-2011, 03:49 PM
#11
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I found out that being an 89 mine uses the dual function reservoir and has a selector valve on the frame rather than a check valve inside each tank. It also has a low pressure pump in each tank and one high pressure pump on the drivers side fuel rail.
03-07-2011, 03:55 PM
#12
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When it fuel level reads 0 and the tank is not empty - it means that sending unit wire is grounded. When it reads "far beyond full" - wire's broken or not connected to sending unit. I'm not sure what kind of fuel tank selection system you have, but you may find it out really easy - if there's a fuel pump on the frame, then you have a tank selection valve. If there's no fuel pump in there - it means that you have fuel pump check valves to select a working tank. The overflowing problem you're describing looks a lot like check valves clogged up to me, which means you have a high-pressure fuel pump in each tank. Just in case I'm wrong (it's still possible) - take a look at the frame (driver's side), to find out if there's anything else except for fuel filter.
03-07-2011, 04:12 PM
#14
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I've never dealt with selector valve (F150 is not a common vehicle in here), but as far as I know - the overflowing problem should be in it. It must contain a lot of solenoids, and apparently one of solenoid-operated valves is stuck open. I guess other guys in here have more experience with that system, and they will be much more helpful than me
03-07-2011, 07:28 PM
#15
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Thats is pretty much it, the reservoir has a diaphram in the top that switches the flow of fuel depending on which tank it's running on. The overflow problem will probably be from it not sealing off right.
You use to be able to get kits to rebuild them not sure if you still can. The only reservoirs that i have seen are in LMC. But you may be able to pick one up at some part house.
Last edited by Nitehawkjr; 03-07-2011 at 07:30 PM.
03-07-2011, 08:21 PM
#16
So the rear tank ran dry and it died. I walked to a station and brought back 5 gallons in a fuel tank. I tried putting it in the front but it started to overflow right away. The truck wasnt cranking with the front tank selected. Its possible that i didnt give it enough time to get fuel to the motor. I put the 5 gallons in the rear tanks and cranked away, it fired up and was running again. I stillhas the fuel cap and door open to the front tank and it began to overflow once the truck was running again. So, this has got me thinking that the rear tank is pumping fuel into the front tank.
Iv done some searches and it seems like there are a couple different systems based on year model. Lots of talk on check valves and vent valves, selector switches and of course the pumps themselves. Im kind of lost, can someone point me in the right direction? Or at least explain how the system is set up to work so i can begin to diagnose all the problems. Mine is an 89 5.0l 2wd 5 speed short bed.
Iv done some searches and it seems like there are a couple different systems based on year model. Lots of talk on check valves and vent valves, selector switches and of course the pumps themselves. Im kind of lost, can someone point me in the right direction? Or at least explain how the system is set up to work so i can begin to diagnose all the problems. Mine is an 89 5.0l 2wd 5 speed short bed.
http://www.stangler.com/motorsports/...alve/index.htm
and check out page #4 on this link as there are two diagrams for your 89 F-150.
http://www.ford-trucks.com/forums/47...tor-valve.html
03-07-2011, 10:09 PM
#17
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That helps ALOT. Looks like the selector valve would be the place to start but it seems like a part thats hard to come by. Im debating whether to replace it or delete the rear tank. Is there a a how to on deleting the rear tank?
03-08-2011, 01:28 AM
#18
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I just read all 9 page of the second link you posted. Since the part seem to be pretty hard to get a hold of or back ordered, i think ill go a different route. Im going to see if the front tank works. I think the rear is almost empty. Im going to switch it to the front tank and hope the truck doesn't die. If it does, i will probably replace the fuel selector valve with a one tank reservoir and remove the rear tank and plumbing. if the front doesn't work then ill do the same to the rear. I don't really need more than one tank anyway.
03-10-2011, 03:31 AM
#19
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Okay, sorry for a later response I don't know if this will help but, my 1990 does the same thing when I switch from front to back. If you normally run on the rear tank switch it to the front and drive it. it should correct itself. that is what mine did. also check the fuse for the selector switch. hope this helps if you haven't fixed it yet
09-07-2011, 04:39 PM
#20
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I'm currently deleting my rear tank and going to try removing the tank selector valve altogether. Just in case I change my mind later, I want to keep the duck bill clip fittings on the fuel lines going in and out of the valve. Don't know if anyone makes a "male-male" fitting to do that. Will let you know what I find out.
