fuel issue
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fuel issue
i bought a 1987 f-150 with the inline six and i am not getting any fuel to the injectors. I have tested i have zero volts at main rail pump. I put in new relay and checked fuse still no power. Tested voltage on switch and i am getting 3.5 volts or so on the out going leads on tank selecter switch. Anygood ideas i spent 8 hrs today with a power probe and didnt get no where. Not to mention the color codes for the wires in my chiltons were no where close to being what i have....
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Joined: Oct 2006
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From: Davis & Newcastle, CA
Hmm... You might have a bad power wire going to the relay. Put the hot probe on your voltmeter on female connector for the 30 pin on your fuel pump relay socket, see if you have 12v there.
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i believe i checked that and had 12 volts on the yellow wire and i checked the fusible link too. This is confusing why i am getting low voltage at tank switch. Is there a good roadmap of this electrical system. haynes and chiltons are about worthless
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Joined: Oct 2006
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From: Davis & Newcastle, CA
My guess is that the tank switch is not inline for the 12v that is going to your fuel pumps, it is most likely wired somehow to the inductive coil on a relay circuit. Maybe someone can chime in to confirm this...
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i think i am going to double check my relay i replaced today. I think i changed the wrong one. doing a search it seams the right one for a 87 would be the one with the green socket...... and i changed the black one.
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Joined: Oct 2006
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From: Davis & Newcastle, CA
Also check to see that your inertia switch didn't get tripped, although if you're getting voltage to the switch then it probably didn't... Not sure about an 87 but I think it should be in the passenger kick panel.
EDIT: Not sure which socket color is for the fuel pump relay but the fuel pump relay socket should have wire colors yellow, red, tan/green, and brown coming from it; while your EEC power relay (the other one) is going to have yellow, white/light blue, black, and red (with a fusible link). Double check those and let us know what happens...
EDIT 2: It appears that the switch IS inline with the fuel pump power so I believe you should be getting 12v at the switch.
EDIT: Not sure which socket color is for the fuel pump relay but the fuel pump relay socket should have wire colors yellow, red, tan/green, and brown coming from it; while your EEC power relay (the other one) is going to have yellow, white/light blue, black, and red (with a fusible link). Double check those and let us know what happens...
EDIT 2: It appears that the switch IS inline with the fuel pump power so I believe you should be getting 12v at the switch.
Last edited by Skandocious; Sep 3, 2007 at 01:30 AM.
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Postmaster
Joined: Oct 2006
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From: Davis & Newcastle, CA
Why did you bypass the inertia switch? It cuts the power to the fuel pumps in the event of an accident... Seems unsafe to bypass it if you ask me...
If you are not getting 12v to the inertia switch then your relay is bad, because the power to the inertia switch comes directly from the fuel pump relay. Power goes ->
battery, yellow wire to
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fuel pump relay, brown wire to
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inertia switch, red/yellow wire to
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tank selector switch, red & brown/white wires to
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fuel pumps
Here's a diagram that illustrates this:
If you are not getting 12v to the inertia switch then your relay is bad, because the power to the inertia switch comes directly from the fuel pump relay. Power goes ->
battery, yellow wire to
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fuel pump relay, brown wire to
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inertia switch, red/yellow wire to
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tank selector switch, red & brown/white wires to
|
fuel pumps
Here's a diagram that illustrates this:
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