1984 Ford Mustang Fuel Pump Problem

Other Category problem
1984 Ford Mustang 6 cyl Wheel Drive Type unknown Automatic 50000 miles

this mustang is a carburator engine and have checkd the relay and resently put a new one have checkd the fuses and are good. When the pump is testes with a 12 volt battery will start but not with the key when fire in it up, change the filter and steal it does not work. I was wondering if its the car alarm that was disconnected since the control was lost and might lockd the fuel pump from the energy source.