If you have Hyundai Santa Fe and you have check engine light and code P0172 system too rich bank 1 and you want to know what could cause Hyundai Santa Fe to have code P0172 system too rich bank ...

long fuel trim maxed out at -39% 

high pressure fuel reading on scan tool is within 2 psi of called for fuel pressure. approx 530psi at idle

low pressure fuel pump is pumping 60psi. spec is 55 psi

baro sensor is reading 14.7 psi. Vehicle is at sea level so reading is correct

used a camera to inspect injector nozzels and verify none are leaking into cylinder 

no vacuum leaks found. 

all hoses are connected and in good shape

capped off evap line to tank to verify not pulling fumes from gas tank

checked fuel ethanol content less the 10%

no contamination found in fuel

i seen some posts about faulty fuel pressure regulator or high pressure fuel pump but havent seen anything that would lead me to believe this is actually the concern here.