So I am a newbie to these fords and I am trying to help friend.

Truck is a 93 F150, 4.9L I6 2wd

I can not get the fuel pump to turn on(this is a single tank system)

is there another way to test the fuel pump without dropping the tank? I can not see any real easy way to get to the fuel pump wiring w/o either removing the tank or the bed of the truck.

I have checked the Inertia Switch and it is depressed and when I tried to jump the wires the Truck would still not fire up.

I can sit there and spray carb cleaner into the TB and it runs just fine. The truck does have fuel(at least 3 gallons that I just put in).

I am pretty sure it is the fuel pump or something in the wiring to it. From what I have read on here It seems like that center relay is the fuel pump relay. I have jumpped a wire from the 30 to 87 post on the truck and it still does not turn on the pump. Anything else I should check before I drop $150 on a new set of pumps and get to dropping the tank?

If I Ground Pin #6 on the Test Connector I can get the Relay to Click on and off. So Is this the last bit of testing I needed to do before I replace the Pump?

Thanks
Mike

 

I give what is a 30 to 87 post?

You can try grounding pin #6 of the DLC with the key on and see if the selected pump runs.

Note:The wire color is wrong in the image below for the 93.
The Fuel pimp wire (#926) for the fuel pump is a blue wire with a orange stripe.

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While the truck only has a single tank it has dual pumps right? a low and high pressure pump?

I know the test connector on the drivers side fender when I ground pin #6 from there the Fuel Pump Relay Clicks but the pump does not turn on.


and post 30 and 87 are the posts on the relay, the completed circuit, so when I bypass the relay the Pump does not turn on either

 

if u cant get fuel pump to run by jumping the self test either the pump is gone or wiring is broken

 

NO just the one pump in the tank inside the FDM.
It does not have an low and high pressure pump.







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Take a test light and see if you have power at both sides of the fuel pump fuse.
Let us know what you find and we can go from there.

 

ok cool, I do not remember where I was reading it was talking about dual pumps on this truck

OK I just checked and both sides have Power

 

Do not look at the two tank set up in the diagram above but the rest of it should be right.

 

ok so ... Now that I know I need to replace the pump what is the best way to do it? have a listing of parts I might want to have on hand when replacing? I will be searching the forums and google in a few for details.

I am on the fence if I want to either Pull the Bed or just drop the tank, Pulling the bed sounds a lot easier as it means the tank gets to stay in place with all of the lines

I have done Fuel Pumps on Volvo's in the car more than a few times so the idea is pretty nice and basic so this truck hopefully shouldn't be to bad

 

How do you now know you need a pump?
Did you have power at each side of the fuse?
With pin #6 grounded of the DLC and the fuel pump relay closed did you have power at each side of the Inertia switch?
If so there is still the fuel pump jumper on the dash and power at the fuel tank plug to check.
Does the fuel gauge read right, if not it may also be a bad ground at the radiator support on the drivers side stopping the fuel pump from running.
Of course you also need a good body ground from the negative post of the battery to the body and not the frame.
Again make sure you use a test light and not a meter for all the power checks in this circuit.

 

Yes
Yes
Dash? more info?
It reads right with the truck off, with the ign on it does not read. Which side of the rad is the ground?


The Owners of the truck have a bad habit of running it out of fuel a lot so I wouldn't be surprised if the pump burned up.

Either way this is the first I heard about the jumper on the dash

How do I access the Plug at the pump to check for power?

 

Where the two tank selector switch is on the dash of a two tank truck you have a jumper there behind the dash on a one tank truck that the plug plugs into that would normally go to the switch.
Drivers left side (seated), engine side near the top.
This is also the ground for a lot of other things.
Very good possibility.
There is a harness coming from the top of the pump (FDM) and runs for about 1 foot from it. You could unplug it to make sure you have power and ground at that point with a test light.

 

Rear Tank Plug:

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the truck is a side mount single tank ... so the plug should be someplace up there? I guess just feel around for it?
And I just check for power at this jumper on the dash?

Today I will be back there with a few more tools to try to figure out what is going on.

 

Something like the photo below then. Use the ground pins in the plug and the power pin for the pump with the test light.
Yes just power.


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