1985 F150 5.0 FI; I'm trying to sort out this truck but the wiring diagrams I have do not give the detail I need. 4 connectors connected to nothing any help appreciated:
1. Under dash (1) red/green thick (2)red/orange thin (1) black thin with a connector end.
2. Under dash red -white -black with a connector end.
3. Under hood under master cylinder yellow thick 1 wire with a connector end.
4. Under hood under master cylinder black thin connector end.

 

What are you trying to fix? Not all connectors are used on these trucks.

 

Starting to figure that out. I beleive the one connector is for a carburated version (Red/green red/orng black).

Trying to get computer to give codes and fuel pump relay to work without grounding out tan wire.

 

First, you know that it doesn't have a check engine light, right? Next, If the EEC relay is faulty, the fuel pump relay won't work either, because the EEC relay turns on the fuel pump relay (and if the EEC relay is bad, the computer won't work). The relays are next to each other, one brown and one green. I can't remember which is which right now. Your whole problem might just be a bad relay. Good luck.

 

Its got an emission light. The fuelpump relay does work when the tan/ltgrn wire is grounded. I would just like the electric fuel pump to come on when the key is on without a homemade ground wire inserted into the system.

 

Yeah, the emission light isn't the same. It comes on after a pre set number of miles. You definitely have something electrical going on if you have to physically jump the ground wire. Can't help a whole lot on that one without seeing it, however. Good luck.

 

The green relay is fuel pump and the brown is the EEC Power relay.
I do not have a 1985 F-series FI diagram but here is a 1986 if it will help.
Should be about the same but the wire colors may be different.

http://i54.photobucket.com/albums/g9...-sel2Tanks.jpg

Can you tell me if you have a Fuel Tank Selector valve/switch WITH wires going to it on the frame or just a Fuel Tank Selector valve with NO wires going to it?
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Sub,

I have a dash mounted factory selector switch and dual tanks, there are wires on the frame rail so I'm assuming without actual inspection that there are wires going to the actual valve which I would guess is under the truck somewhere. Not using the rear tank currently.

 

I will guess then that you do NOT have any wires going to it and the diagram I posted should be right.
I was just curious about some diagrams I have seen and just wanted your help.

 

I'll physicaly check later today.

 

See if the selector valve looks like photo #1 or #2 below.

Photo #1 no wires:
http://i54.photobucket.com/albums/g9...ectorvalve.jpg

Photo #2 wires:
http://i54.photobucket.com/albums/g9...tfuelvalve.jpg

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Photo #1

 

The diagram above I posted above is the right one then.
If the fuel pump relay does not come on when you ground the tan/ltgrn wire and it comes on with the switch he put under the dash then I would say he cut the tan/ltgrn wire off the relay and ran it to the switch on the dash.
You will have to rewire the wire from the relay (tan/ltgrn wire) and wire it back to the self-test connector and pin #22 of the EEC (ECM) Computer.

 

Fuel pump does come on when grounding T/LG I have continuity between pin 22 on eec connector and relay. What it doesn't do is turn on without the T/LG wire grounded. I bought a reman computer I'll let you know if it does the trick.

 

With Subford's and others help Fuel pump problem solved. Replaced both eec power relay and Fuel pump relay first, no love but with new (reman) eec works like a champ!!!