I need help please... I have a 1988 F150 standard truck. The motor is a 300 six cylinder 4.9. It does not have air conditioning, no power windows or l ocks. It is a basic truck. This fuel pumps in both tanks are not working. All fuses under dash are working. I replaced both relays under the hood with new ones. I replaced the ignition coil and it is getting a good spark. I removed all the connections on the solenoid and sanded each connection to remove any rust. I confirmed the solenoid was working properly with my test meter. I replaced the tank selection toggle switch on my dash with a new one. Both fuel tanks are full of gas. I used a rubber hammer to hit each tank hoping it would caused the fuel pum ps to come on and did not work. When I turn the key to the on position I can hear the high pressure pump cy cle on for about 2 seconds but i cannot hear the pumps in either tank come on. I can spray starting fluid into the throttle body and the truck starts with ease and runs very smooth until the starting fluid is completely used. The past two mornings I went out to try to start it and when I turned the k ey to the on position I could hear the fuel pump in the rear tank come on. Yesterday morning the truck ran smooth for about 4 minutes and then shut do wn and would not start back up. This morning I could hear the fuel pump in the rear tank and started the truck and it ran pretty rough for less than 1 minute and would not start back up. The fuel gauge shows empty when the front / rear toggle switch is on the fr ont tank. When it's on the rear tank the fuel gauge shows full. I tried to pull codes from the computer by jumping the EEC and the check en gine light stayed on and would not work for me.
Question: If the tank selector valve under the truck was clogged.. would th at prevent both tank pumps to come on?
Thank You Very Much for any help provided!!