Unless you have high side pressure readings, you can't expect to get a proper diagnosis. If a compressor runs constantly, but there isn't much change between high and low side pressures, the compressor has failed.
Get the proper tools to diagnose it or pay an auto repair shop to diagnose it. After paying a repair shop for diagnosis, you can pay them to recover your refrigerant, replace your parts, then pay them to vacuum and recharge the system.