R32 GTR Catalyzer Light Comes in high RPMs

[BourneToLive]

As the title suggests, my catalyzer light came on today when I did a small pull, hitting around 5500 RPM, barely hitting boost. I run an Apexi PowerFC with 2860 -5s. I don’t have a catalytic converter. My car is straight piped and the sensor isn’t even plugged in to anything. I assume it could be a tune issue, as my Inj Duty hit 91% and I know it’s supposed to be at tuned to 80%, and it is. But I honestly don’t know much. I’ve seen other posts saying it could be that the MAFs are maxing out. I only run 1.3 bar of boost, or roughly 17psi. I’m stumped. Does anybody know? 

Edited February 2, 2021 by BourneToLive
Additional info

[Duncan]

The PFC uses the cat overtemp light to flash when it detects knock, so there is an issue with your tune in that area. 

Injector duty at 91% is not really a problem on it's own, in theory even up to 100% is OK but if it ever calculated that it need 101% or more it will be leaner than planned and engine damage is highly likely, so staying under 90% is safer.

In this case it is more likely you had too much timing at that point in the map for your engine. 

Don't rely on 30 year old electronics to detect knock and help you tune. Your tuner needs proper knock detection and tracing of the map to work out where it occurs, to correct that part of the map.

[GTSBoy]

Also, if the tuner tells you that the injector duty cycle shouldn't need to exceed 80%, and it is hitting 90%, then it could suggest a fuel supply problem. Dying pump, dirty filter, dirty injector(s), etc etc.

Don't drive it hard until you've had it diagnosed.