I considered running a wire to the pump, but even when the pump was disconnected, the FI fuse was still blowing, so the injectors wouldn't have fired. After a total of 9 hours of work between fuel pump (rusted bolts snapping off, drilling/tapping new holes, cutting the floor to access the pump without dropping the tank entirely) and searching for electrical gremlns, it took one of my friends 5 seconds to find the problem.
He had us put a new fuse in and turn the key while he listened under the hood. The fuse blew, expectedly, and he heard a click come from a sensor in the bay... the one with the Mitsubishi logo on top of it at the front of the engine (by the coolant temp sensor). He disconnected it... it fired right up. The short was coming from inside the sensor.
Here's the frustrating part, last month when I replaced the water pump, I remember disconnecting that sensor and cleaning it because there was this tar-like goo inside it. A month later, the connector that I cleaned is the cause of an electrical short.
So she's all done, but I can't reconnect that sensor without blowing the FI fuse. (Anybody know what that sensor is so I can replace it? Seems like an emissions-related sensor, which would explain its involvement in the FI circuit.) This post was for the purpose of anyone searching for electrical causes to fuel system failure in the future, as well as to let everyone know that it's resolved.
