Hi guys and gals. Just purchased a 1998 DX HB d16y7. The guy i bought it off of installed a stock header from an ex due to the original header cracking he connected one 02 sensor and disconnected the other. My question is how do i determine which plug is for the primary and the secondary? i want to be sure it is hooked up correctly when i get the full exhaust system in a couple of days. one plug wire looks longer than the other but was not sure if that was the deciding factor. i will get a pic up of the engine bay asap.