1994 318is

[Flash635]

What would cause it to run extremely rich evrywhere in the range?
Thick black smoke.
The only thing I know is it's not the FPR and it does it from cold leaving out the O2 sensor.

[shogun]

thick black smoke means too much fuel, possible causes:
clogged air filter
faulty sensors such as air intake, coolant
FPR = how can you be so sure that the fuel pressure is not the problem? Did you test the fuel pressure? Remove the vacuum hose from the FPR and see if in the hose is fuel. If so, the diaphragm of the FPR is damaged.