Originally Posted by
murfie
I'm not sure how familiar you are with PIDs. The closed loop fueling system is just a PI controller. There is no derivative, this makes it better for steady state conditions. With out seeing a log of the behavior you are seeing its hard to advice on what to do to the proportional or integral Gain. If its oscillating as you say increasing the integral could make it worst. If the headers are allowing the sensor to get a smoother signal from better exhaust flow at idle then the proportional values may be to high causing the integral values to over compensate for the increased offset. In that case increasing the integral would cause it to get to steady state quicker but with more oscillating before doing so. The PI control seems to be for low RPM areas so it could be the cause of the issue. Just to cover the basics just make sure its not a bad maf curve as that is the main input to this controller. bad in bad out.