Foxbody fuel pump not coming on / no start

Finally found a really good welder that would tackle floor pan replacement in our 87 Mustang SSP project. Saved my pennies, drove the car over to his place and - shazam! A few weeks later, new and absolutely factory looking floorpans. Purty kool eh!   But....  No start anymore. Absolutely NO cough. Nothing. Just turning over.       Not out of fuel, More in the tank, some on my shoes. Plenty of spark (ask me how i know)      He has rechecked everything that he took off/ apart. All looks in order. He says that he can hear /feel the fuel pump relay clicking but i did not hhear the fuel pump run. And on an old Fox, you hear it. So how to properly diagnose?   

Sure sounds like a dead pump, you could try hotwiring the pump to rule out any other electrical issues with the pump circuit.

Fuel pump relay is under the front seat, green maybe, you can jump that.   Inertia switch in the trunk by the drivers side taillight, push the red button.  Lone wire near the brake booster, I don't remember if you ground it or give it 12v to bypass all and just run the pump.

If those three don't get you fuel, drop back a few and punt.

The pump -could- have chosen that exact moment to expire i suppose.  Unrelated to all of the unplugging, welding and plugging. Does not compute to me but anything is possible and something is wrong so...   

My vote was inertia switch had that one trip when I went over a bump on a trackday.

So i have had this same thing happen to me in the past. it was a capacitor in the computer going bad. But since you hear the relay clicking which is downstream of that, it should come on. You can start by swapping the fuel pump relay with another and see if it starts, if he welded floor pans there is a chance he melted wires running along the side of the rockers. As mentioned above, they have intertia switches that you can try to reset. you can try to shoot power to the pump via a power probe. start at the wiring just outside of the tank and if it comes on you know the pump is good. then keep working your way further away on the circuit until it no longer comes on. then you can figure out where the disconnect its.