UART CO2 sensor interfacing with ESP8266

I have a DFROBOT CO2 sensor THIS sensor to be exact. It is suppose to operate at 0-3.3v on UART bus. I tried the sketch with Arduino UNO and it works. but when i try this with ESP8266 it does not work. On the ESP i tried to use softwareSerial and Serial.swap() to move the pins to another UART ports but it still dont work. I have been to the SoftwareSerial library github and asked but they concluded this is a hardware issue. Why don't this work? From my understanding the ports don't need a level shifter do they? the sensors UART is 3.3v so this should be fine for the ESP8266. does anyone have any idea why this might not be working??

Nevermind Figured it out