bank1 sensor 1 2000 honda civic ex 5 speed...help help help?

[Ben978]

hi everyone i have a 2000 honda civic ex...but the problem is it seems that the previous owner had a different engine harness in the car...there is alot of leftover plugs that are not connected...but some how he made it to start....cutting and wiring...i had a engine light came on when i baught it from him.he told me its just the o2 sensor....there is no catty down there..st8 pipe...i took it to the gargage and let them weld an o2 bung and replace it with a new o2 sensor....but the light stayed on....then i replace the exhaust manifold o2 sensor and the light is still on...what the fuck is going on???i had a scanner and it came up po135 bank 1 sensor 1...i did replace it....do i need the oem engine harness and do it over...???or a catty converter? or any ideas or trick to get rid of the problem???????please help my friends from yahooo. thanx