I removed my catalytic converter and just have a straight pipe in it's place, I took out the o2 sensor and welded it into the pipe but my check engine light still came on. So is my check engine light going to keep coming on because I have no catalytic conver?

 

Why did you bother? A cat converter doesn't restrict the flow all that much. Besides, it is a federal offense with about a $2500 fine if you get caught. Anyway....

Asuminging your are refering to the senondary O2 sensor....
Did you weld a threaded bung onto the pipe or directly weld the O2 sensor? The secondary checks for cat conv efficiency. No cat=no efficiency.

 

I welded a bung to the pipe. it's the secondary o2 sensor the wires didn't match though it was four wires two black one white and one blue but on the o2 sensor one wire was green. would the wires being switched cause the cel to come on?