10 yrs dead

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Dec 5, 2017 | 06:46 PM

Deadtruck

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10 yrs dead

Hello I am new to forums and unsure of proper protocol so please forgive my ignorance.
I have an 89 F-150 regular cab long bed with dual tanks. 5.0 with standard trans 4x4.
The truck has been sitting for several years. I changed the oil, fogged the cylinders, new spark plugs etc.
I knew going in there would be grounding issues so I made those necessary repairs and established several new grounds also.
Truck started right up with a new battery and a shot of starting fluid in the throat.
My issue is fuel. I have power to all three fuel pumps with key on. But none of the three will turn on.
(Probably the wrong thing to do but I was trying to see if it was a ground problem)... So I hooked test light to positive power to try to draw some type of conclusion.
In doing so, the light lights on every pin for all three pumps.
What does that tell me?
Besides that I'm a moron and I don't know what I'm doing?
Where do I go next and what do I look for?

Thanks in advance for any help you can give me!

Dec 5, 2017 | 07:50 PM

Conanski

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Joined: Jun 2006

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From: Ottawa, Ontario

Fuel pumps don't last very long when not in use, you can blame it on modern fuels if you like the ethanol they add gums stuff up pretty quickly. So no you're not a moron but you will be a little poorer once you get this fixed. Welcome to the forums.

Dec 5, 2017 | 07:51 PM

ChRoNo16

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Joined: Dec 2010

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From: Shafer, MN

that you have complete circuits.

Have u tried replacing the fuel pump relays? I know the high pressure has one, not sure if they all run off of it.\

Im also not sure but the 89 may have a fuel pump inertia switch, if its failed or tripped they wont run. its usually located behind the passenger side outer kick panel./

Hope this helps.

Dec 5, 2017 | 08:02 PM

Deadtruck

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Thanks. Yeah I figured I'd have at least one bad pump.. but all three? It could happen..
Something I forgot to mention originally was the fuel gauge stays pinned over full. For both tanks. (Even when pumps are unplugged)
So should the test light be lit on all the pins when testing from positive power?

Dec 5, 2017 | 08:09 PM

Deadtruck

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Yes it does have an inertia switch. Driver side kick panel area. Has power and reset

Dec 5, 2017 | 09:48 PM

Conanski

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Posts: 31,930

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From: Ottawa, Ontario

If you have power at the fuel pump connectors there is nothing wrong with the inertia switch, dash switch or the fuel pump relay.

Dec 5, 2017 | 10:29 PM

Deadtruck

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Thanks for that answer. Only thing I haven't tried is supplying direct power. I will try that to rule out the pumps. At least the high pressure pump, as that one is two wire, and I don't know which two, of the four wire connecter on the front tank are for the pump.