luvmy88

After going thru a couple frame rail mounted fuel pumps, pulled the bed off, dropped both fuel tanks which were full of rust, replaced the side mount tank with new sending unit and pump, deleted the rear tank, capped off the two ports for the rear tank at the frame rail mounted switching valve, flushed the fuel lines, replaced the fuel filter, now's she's a no start. I'm asuing there must be something that maybe needs to be rewired with the dash mounted switch (yes it is in the front tank position) or the frame rail mounted switching valve. Any help would be greatly appreciated, I have a golf ball sized bump on my head from banging it against the wall....

jezter

I had to take mine to a mechanic earlier this year because of dual tank/electrical issues and had him put it in a single tank configuration... he bypassed the rail switch totally and is all run direct using the rail and in-tank fuel pumps... so the switch inside the truck now controls nothing, I think... havent tried switching it to see if it disables the front fuel pump... will try it and see... hmm...

in-tank fuel pump to rail fuel pump up to fuel rail... overflow/excess fuel line directly back to tank...

koja7296

What year truck? How many port selector valve?

luvmy88

Thanks for the quick reply, I just joined this site about an hour ago. I was hoping to be able to work thru it without having to take it to a shop. At least I now know what has to be done, just need to find a wiring diagram to find out how to bypass the switching valve and the dash switch. Thanks again!

luvmy88

She's a 88, The swtich valve has four ports in, two out.

jezter

no problem... I was in the same boat earlier this year... except mine was created by a botched job from a shop that shut down right afterwords... too much money wasted for nothing... at least the mechanic I found worked for Ford for 30+ years and knew what he was doing... the electrical was messed up, both tanks had bad pumps, and the switching valve had parts missing...

yea I am not sure on the electrical part of it... I have not looked at that part since he did that work... I need to just to make sure I know in the future in case something happens...

klricks

I have wiring diagrams from an '86. See link in my signature

luvmy88

Thank you very much, great info! With the wiring diagram you have, either myself or my son will be able to figure it out, he's much better at electrical stuff than I am.

klricks

After re reading your original post I see that your are attempting to use the selector valve with one tank. The valve operates by fuel pressure provided by the in-tank pumps. Both tank pumps must be operational for the valve to work properly. There is no electrical components of the valve itself and it's probably jammed in the wrong position. I think you need to completely bypass the valve.

For the dash switch you can remove the switch and put a couple of jumpers on to bypass that. One for power to the pump and one for the gauge circuit.
Note that even if the in-tank pump is not powered or not working for some reason, the engine should still be able to start and run. The frame mounted high pressure pump will struggle and make lot of noise but the engine should start.

Here is a wiring diagram from the Ford manual ('86 5.0l):
http://img222.imageshack.us/img222/2...altankdia1.jpg

luvmy88

Great! Thanks again for the info about the switching vavle and the wiring diagram. I noticed the inlet at the switching valve is 3/8 and the outlet to go to the pump is 5/16, do you know of an adapter to connect the two plastic lines together? Thanks!