89 deville won't start after sitting for a month

I bought my caddi from my mom who said it was acting up so she stopped driving it. I got it about a month or so after that. I started with plugs, wires, cap, rotor, idle speed motor, ignition module, fuel pressure regulator and new computers. Still won't start, it'll turn over though. THE code for battery voltage meter reads 0 on the information center. Altough it will run for 20 or 30 seconds if I disconnect one of the fuel injecters but its very weak as if its getting to much fuel or too little air. Any suggestions will be appreciated

Welcome to AF, will it run on carb cleaner sprayed into the intake, have you checked fuel pressure?