If your FCD is set for 1bar, anything over that the ECU will keep pumping in fuel as if it was at 1bar.
That will be ok for a few more PSI (maybe 16psi) until it does start running out of fuel and leaning out.
Having a wideband 02 is a VERY good idea, as they you can be sure you are not leaning out and going to destroy the engine.
