mystery wire

I'm still trying to figure out the cold start issue and I have traced it to the relay that controls the fuel pump and ejectors. I replaced the relay in the beginning. I have the Chilton and Haynes books so between the 2 I have discovered that there are 2 black wires with a red stripe on the plug. the smaller one goes to the injectors and the vacuum valves by the battery. it seems to be fine. the books state that the larger black/red wire should be hot when the key is turned on or in start. Mine has no power at all and in fact it is grounded. I have for the last two days attempted to locate the other end of this wire. it is suppose to go to a fuse and then the ignition. None exists anywhere under my dash. There is one coming out of the harness from the key switch to where it plugs into the wiring harness but where that wire connects there is no wire on the other side. I did find the wire on the other side of the fire wall but have not wanted to totally tear the wire bundle apart. Does any one know where this wire should come out under the dash and where is the fuse for it. Oh there is no b/r wire coming into the fuse panel. I'm thinking I might just run a new wire but have no idea what size fuse to use and the books only say "fuse". this is the wire i'm looking at. Any idea what "refer to P. 851.75" means
Attachment 20228

I have discovered that the black with red stripe wire is connected to the starter solenoid black wire. Still don't see a fuse any where

that means it is the hot wire to the coil to supply power to the coil when starting. If that is not connected to the coil, you can crank all day and it won't start, although it might when you let off the key if everything else is working. Look at the coil wiring and reinstall it where it belongs. If the Bendix on the starter is not engaging, then the issue is in the ignition switch circuit.