Official list of possible reasons for running rich (please list)

[nicknorth11]

I'd like to have a comprehensive list of potential causes of running rich. I'll start the list and update it with all responses.

EMS set incorrectly: wrong injector global, deadtime, too much fuel added with individual adjustments (ie. Sliders in ecmlink)

Airflow reading is incorrect: ECU is being told more air is coming in than actually is. (boost leak, faulty MAS/MAF)

Front o2 sensor reading falsely lean: bad o2 sensor, break in sensor wire(s), exhaust leak before front o2 (cracked exhaust manifold, leak between head and exhaust manifold, leak between turbo and o2 housing, leaking turbo seal)

Rear o2 sensor (wideband) reading falsely lean (only when using rear o2 to simulate narrow band o2 sensor with EMS): bad o2 sensor, exhaust leak before rear o2 sensor

Coolant temperature sensor reading incorrectly: bad sensor, break in sensor wire(s)

Fuel pressure too high: afpr set too high, too much voltage to fuel pump

 

[Zbuschur]

Looks like you got a lot of them the only other two I could think of is if you vta you bov without retune and a MAF. The other is maybe if you too out the honey comb but I don't know how much that would effect it

 

[boosted1stgen]

Restricted or plugged exhaust/cat converter