Fuel problem, cranking but no start. Battery draining.

I have a 1991 Buick Century 3.3L V6 w/ 180k miles on it. I bought it used in 2002-03 with @ 141k and had the fuel pump & strainer, injectors, pulsator assembly, O2 sensor and filter replaced (was reamed on charges). I'm positive the fuel pump is ok because I hear the humming sound described by mechanics. I hear it when gas gets low also, the car whines until I fill up. I have tried spraying carb/choke cleaner in the TBS(?) And starting with no success. My main problem with troubleshooting is finding the exact location and/or descriptions of parts to inspect and/or test. I cannot afford to have it towed again so I have an auto manual to assist but find it difficult and risky to go further into the fuel system not knowing exactly where the fuel pump relay, fuse, TBS and all the sensors are. Could you tell me how to locate the parts or provide a diagram specific to the '91 buick century? Picture and possible donation to follow.