Fuel Selector Issue

[fords4life]

So.... The selector switch does not switch the tanks on my 86, nor does it switch the gauge. I bought an NOS switch at a swap meet for a decent deal but it is the 5 pin and I have a 6 pin.  Decided to try to check some things at the switch since it was apart but my wire colors do not match any of the wire colors in the 86 EVTM. Front tank works just fine but I get nothing from the back tank.  I still need to crawl underneath and check the rear tank connections.  Here are the wire colors I have:



Am I missing something in the EVTM?

[NotEnoughTrucks]

Carbureted or fuel injected?

There is an interesting discussion going on in Gary's Big Blue thread. I think that 5 pin switch may be for the carbureted truck with the 6 port valve.

[fords4life]

EFI

[Gary Lewis]

It looks to me like the wires match very well.  I suspect you are looking at the wrong diagram.  Look at Page 104 here: Electrical/EVTM/1986 EVTM/Electric Fuel Pump Control.  Or, look here: Fuel Systems/Fuel Systems Wiring and look at the 5.0L tab.  Same page from the EVTM, but the latter shows the 5-pin vs 6-pin switch and gives you part numbers.

But confirm that you don't have a switching valve on the frame rail.  You shouldn't, but just to make sure....

[fords4life]

Apparently I've lost a page of the EVTM and didn't realize it. I did not have that diagram. Now I feel like an idiot.

No switching valve, just the "reservoir".

[Gary Lewis]

Idiots don't ask questions.    Glad you did.

[fords4life]

So I confirmed the rear tank sending unit/pump is plugged in.  Next up is to confirm that the truck is sending power to the pump when I flip the switch.

Does anyone have the shop manual that could post the Ford diagnostic stuff for the dual tank system on a 5.0?  The EVTM only references a couple of things.  I have checked all but the G201 ground down by the drivers side kick panel.

[Gary Lewis]

I have an '85 shop manual, but the setup you have came out mid-year so it may not have it.  I'll check in a bit - after I finish this cup of French Roast and enjoy the sun coming into our sun porch while it is 17 degrees outside.  

[fords4life]

Thanks and no rush.  I doubt I'll be doing much on it until this weekend or next week.  The schedule this week is a little hectic.

[Gary Lewis]

Ok, I put up what the 1985 shop manual says on this page: Fuel Systems/Diagnostics. However, it shows just what the 1985 EVTM shows - that the 1985 EFI'd 5.0L had a 6-port fuel tank selector valve.  But Bill says he's never seen one and thinks all the EFI'd 5.0's came without it.  Besides, yours in an '86 and the '86 EVTM doesn't show one.

So you need to ascertain if your truck has one.  I don't think it does, so that procedure really won't help you.  And I don't have a 1986 shop manual.  Sorry.

[fords4life]

Thanks!  But your are right, there is no 6-port selector valve.  I have the low pressure in tank pumps, reservoir/"selector valve", and high pressure pump on the frame rail.  Absolutely nothing happens when I move the switch on the dash to the rear tank, it just keeps pumping and reading the sending unit from the front tank.

[Gary Lewis]

Let's make sure we are on the same page.  You said you have a reservoir/"selector valve".  Do you mean the dash switch?  Or, the valve shown below, right in the middle of the page, called the "Tank Selector Valve".

You shouldn't have anything on the frame rail but the high pressure pump.  Right?

[fords4life]

Below is what I have on the frame rail.  The 9K044 Reservoir and Selector Valve with no electrical connections and the high pressure pump just after that.

[Gary Lewis]

Ok, now we are on the same page.  And I don't have any manuals that will help you.  Perhaps someone else?