keeps blowing 20a fuel fuse

have a 96' neon... ran great!!!! always started with no problems.. well problem now,,... had car started in garage and shut it off.... went to move it out of the garage and wouldn't start.. battery is dead so was using a battery pack... still wouldn't start... didn't hear the humming of the fuel pump, so started checking fuses... found the 20a little fuse was blown, replaced it and everytime i hook up the jump pack and turn on the pack, it blows the fuse again... even with no key in ignition... used to listen to music while it was in garage... would that blow out the pump? not sure what to try first.... bought a used pump and now i need the gasket for the tank... was wondering if i'm on the right track or not... seen on here that the o2 maybe? plz help!!! not really wanting to sink alot of $ into it... any suggestions would be greatly appreciated!!!! thanks in advance...~Ron

Check the wiring to the O2 sensor. It is probably shorting out on the axle and blowing the fuse. Common occurrence on the neon.