I use a '78 FPR at the end of my aluminium fuel rail. Down the road if you think that may be the problem you can get the '78 for $30 or $40 from rockauto.

That is the combined relay.  Spendy.

I mis-wrote, there's actually even one more connector after the one by the passenger seat.  If you open the passenger door, remove the sill plate, and peel the carpet apart at the seam, you'll see the connector.  Attached a picture with wire colors.  Notice that there's also one  farther back, probably behind one of the plastic panels.

Also attached a picture of the EFI relay wiring.  Not easy to figure out, you'll probably need a meter to be sure.

57 minutes ago, Zed Head said:

That is the combined relay.  Spendy.

I mis-wrote, there's actually even one more connector after the one by the passenger seat.  If you open the passenger door, remove the sill plate, and peel the carpet apart at the seam, you'll see the connector.  Attached a picture with wire colors.  Notice that there's also one  farther back, probably behind one of the plastic panels.

Also attached a picture of the EFI relay wiring.  Not easy to figure out, you'll probably need a meter to be sure.

Spendy? Oh yes. They don't make them anymore, so I had to track down a NOS one on eBay. About 80 bucks... but worth the peace of mind. 

Alright, so there's a green wire with dark green stripes that runs through the whole deal on the passenger side, and that's the positive lead for the fuel pump. Alright. I'll try to track down these junctions, check their conditions, and check voltage. 

Thank you for this diagram! Where did it come from?