B4001 IFR settings

[billiardcue]

B4001 IFR settings question.

If you increase the IFR settings does it make the car run richer or leaner?

[joecar]

In open loop:
leaner (because the PCM now thinks each squirt is now bigger, so it opens the injector for less time to achieve the same commanded fuel mass, but the injector size has not changed so it squirts less).

In closed loop:
the PCM applies STFT/LTFT correction toward achieving stoichiometry.

[TAQuickness]

Just for the sake of splitting hairs, in CL, you will initially run leaner until the PCM adjust the fuel trims to compensate.

[joecar]

Yes that would be correct, it takes the PCM some time to adjust.