First off thanks guys for helping me out on this. Without the help of this forum I'd probably be bringing this into the shop.

Yesterday I tried to start my '01 Navigator. Cranked fine but couldn't get the truck to start. Left it alone and went to work hoping that because it was cold maybe a line was frozen or something. Got home yesterday from work and tried again to no avail. Listened to the fuel pump with the key in on and I could not hear it start. Checked the fuse which is fine. Swapped the relay out with a spare and the truck ran fine. Turned it off and ran to the parts store excitedly. Put a new relay in and the truck wouldn't start again. Swapped relays and still wouldn't run again. Left the truck overnight and started again today.

Today I pulled the connector for the fuel pump. (BTW you can easily reach the full pump without pulling the tank if you remove the exhaust and the spare tire. This might help for the guys not wanting to drop the tank next time to replace) The connector has three connections. Red is completly dead. The middle connector has about 5 volts. Next I moved to the inertia switch. Inertia switch has 12 volts initially for about 2 seconds then drops to 6 volts (I don't know if this is normal). The fuel pump fuse and fuel pump relay have no voltage to them.

I'm at wits end trying to figure this out. Any help is much appreciated. Sorry for the long post but I wanted to give as much detail as possible. Thanks again guys.

 

Remember that you won't hear the fuel pump with the key in the on position for more then just a second. To keep the fuel pump from burning out with the engine not running, the fuel pump will only allow enough fuel to start the engine. The ecu then must see the engine running thru the crank or cam sensors, to allow the fuel relay to activate the fuel pump.
With the start again, stop again issues, I'd bet it's the fuel pump itself. Have you changed out the fuel filter recently too?
I'd test the fuel pressure at the rail before anything else, expecting between 40-50 psi.

 

The positive wire going to the pump motor is PK/BK and the ground is BK.

 

That's normal. You won't see power there again until the PCM detects that the engine is firing (accelerating crank signal frequency).