Yes (I've done so) to the following items I've checked for fuel at the Schrader valve: nothing. I've listened for the fuel pump running after the key is switched on; nothing. I've checked the fuel shutoff switch; there is power on both sides of the switch when the key is in the "on" position. There is a red lead from this switch that I believe goes to the pump. However, on the harness going into the tank (I've checked both red wires), there is no power. I've checked the fuse panel but cannot find any fuse that is labelled as belonging to any fuel system. I've noted that a user listed the fuses for a '93 Cargo van wherein it clearly lists one for the fuel pump. Is it possible that 1) my '86 DOESN'T HAVE a fused fuel pump or 2.) the fuse isn't listed but is part of another fuse on that same panel?

 

Is it possible for you to jumper some power directly to the fuel pump? This will at least verify that the pump is working.

The fuel pump will only run for 2 seconds right after you turn on the key to pressurize the fuel rail. Did you hear that? Is that when you checked the Schrader valve for fuel? The pump will not run after 2 seconds, unless the engine is running. So what you measured at the relay is not providing you with accurate information. I believe most of the switching is done by shorting the negative side of a circuit to ground, so the positive side may indeed see +12v all the time when it's not running. Can you put a volt meter on the relay and do a key-off then on to see if it shows something for about 2 seconds (like going from +12 to 0, then back to 12)?