I have a 1991 Ford F150 6 cyl. 4x4 sh. bd..
I am not getting any power to my fuel pumps. Here is what I have tried so far.
1. Checked all fuses (fine)
2. Disconnected the fuel lines from both tanks. Tried cranking the engine and the pumps are not pumping.
3. Replaced the fuel pump relay with a new one. ( no change)
4. Repalced the EEC relay with a new one. (no change)
5. Checked the connection on top of the front tank. (fine)
5a. Checked the wire harness with a volt meter. There is no reading for volts at all. The ground is working fine.
6. Checked the inertia swich. (it was not tripped.) Also just checked it with a ohm meter. (Switch checks out fine).
6a. Did a volt check at the wires for the inertia switch with (koeo).
green w/ yellow stripe = 6 volts
red w/ yellow stripe = 0 volts
7. Hooked up an exterior in line fuel pump with a hose shoved in the fuel tank. (truck runs fine like this.) Pump was installed just after the in line filter.
8. I just checked the wires on the fuel relay plug. This is with the (koeo) key on engine off.
RED = 12volts
yellow = 1 volt
green w/ yellow stripe = 6volts
green w/ red stripe = ground
9. Voltage check on the EEC plug
yellow = 12 volts
red = 2 1/2 - 3 volts
10. I have now cleaned all the connectors on the fender area and reconnected with a conductive grease.

Now I am out of things to check. What would be my next item?
Thanks in advance for the info, Nels

 

Check the tank selector switch. The wires to mine are getting a little hot, which has slightly melted the switch causing 3 connections to move away from the contacts of the switch.