Cadillac Repair: 91 fleetwood fwd need jumped always, correct voltage, charging system

Question
My 91 fleetwood has a new motor new everything exept alt and powersteering pump lately I have needed to jump it to get it to turn over. You can hear the fuel pump engage but all it does is buzz I have an aftermarket sidewinder alarm but  that woulnt make it not start at least I don't think so anyway once in a blue moon it will start on its own but mostly it needs a jump and it turns right over. The battery is new and holds a sufficient charge any advice?

Answer
Have you had the alternator tested with the alternator on the vehicle to make sure that the charging system is actually putting out the correct voltage and amperage to charge the battery correctly ?. It is possible that the charging system is not working correctly.. TDrive it down to any AutoZone parts store and they will test your charging system for free.