98 f150 5.4 4x4
Will turn over but won't start. Put a brand new complete fuel pump but won't kick on. Tested the wires to the pump And no power. The relay is good the fuse is good. Relay clicks on and gets power but no power to the fuse. I checked the fuel shut off switch and that's still down and ok. Removed the line from the fuel filter and no fuel coming out upon turning the ignition on. Not sure what else to do or check please help. Thanks.

 

I'm not sure what it is, maybe the truck has factory security system that shuts the fuel off?? Maybe the fuel cut off switch is bad, I have heard of them going bad..

 

Heading back to the pick a part tomorrow since they just got in the same truck the other day. Gonna grad that pcm and will also grab the cut off switch. And idea in how to remove the pcm? When removing the kicker panel on the passenger side I noticed a blue box their ( which I'm unsure what that is for ) and to the left of that closest to the fire wall is a silver box which I'm guessing that is the pcm?

 

Sorry, can't help you there .. Not that familiar with them... I think the cutoff switch is suspect .. Hopefully somebody will chime in

 

WHICH fuse????

If you don't have power to the fuse that is supposed to supply the fuel pump circuit, you've wasted all your time and money trying to "fix" something that doesn't have any power. Kind of like replacing all the parts in a TV set that doesn't work after already finding out that the wall outlet that it's plugged into isn't supplying any power.

The 98 does NOT have any factory security system that disables a fuel pump.

If the fuel pump relay energizes for about 2 seconds when the key is first turned to RUN from OFF, the PCM is doing what it's supposed to do.

 

If the fuse is in line AFTER the relay and it's not getting power when the relay clicks it sounds like a bad relay to me.

-Steve

 

It was time for a new fuel pump anyways. But got a new relay and same issue no power on the fuse under the good next to the realy... It's In slot 19 and is a 20 amp fuse.

 

Hood*

 

F19 is an ALWAYS HOT fuse and is before the fuel pump relay.

You need to repair the supply circuit fault for F19 before you waste more time and money.

 

Where is this circuit located? Or this supply circuit for 19?

 

It's all inside the underhood fusebox.

 

Well fuse 19 is getting power now and the relay is fine but still no power to the pump.. Theirs another relay box next to the big fuse box under the good.. But the book doesn't have anything on those relays on the side of the big fuse box.

 

Hood**

 

Ignore the smaller relay box, it's for your trailer lighting.

Since you have proven that F19 is supplying power, how have you proven that the fuel pump relay is energizing and is good?

The fuel pump power circuit is very simple: Power from F19 is on the normally open contact of the relay all the time. When the PCM powers up, it is programmed to energize the fuel pump relay for about two seconds (ONLY!) to pressurize the lines. When the relay is energized, it routes power from F19 to the inertia switch. If the switch is properly set, it will rout that power to the fuel pump and, barring any other circuit faults, the fuel pump will have its operating power and will operate.

 

You can hear the relay Click on when you turn the key and hear it switch off. I also bought a new relay and put that in and still no power to the pump. I have the fuel line disconnected from the fuel filter so I'll know if it's priming or pumping fuel. I checked to make sure the fuel switch is still down which it is.