I have an A/F ratio meter on my turbo timer that is tapped into the 02 sensor wire off of the ecu. I installed my catless uppipe and downpipe and now I have no reading. Does this sensor wire get it's readings from the egt probe that was in my stock uppipe? If so, where do I tap into now to get my readings? The 02 harness from the rear 02 sensor in the downpipe?