New to the whole Harley thing, Not sure I understand this tuner thing? Most of the tuners I look ot take the O2 sensors out of the system
What is the point? they are the main part of any fuel injection system to my knowlage, as as automotive tech, the thought that "A set of pipes, or a air cleaner" can change anything a ECU can't compansate for is hard for me undersatnd, or are the fourm users just suggesting that the factory system is really out of wack!! to start with? Too me if the 02's sence a lean condition the will add fuel as required,
Will a stock '07 run ok with the addtion of a set of pipes? with out a tuner?

 

The ECU's can compensate for a small varance. They don't have an unlimited amount of range. You might get 10% adjustment.

 

When the ECU runs in a closed loop it uses the O2 sensor to tell it if the system is rich or lean. When you change the paramiters by giving it gas it runs in open loop and uses the rpm and tps to run the amount of fuel it's told will be right by the map that has been installed in the ECU, only when the paramiters are constant does it run in closed loop, but even in closed loop it still checks it's reading with what the map says is right and makes the compensation based on this. By taking the O2's out of the loop the ECU has to rely on what the map tells it is right.