I have a B36 with 150 ECU from an 89 7 series in my 77 E-12.
The car would not pass smog due to high NOx and virtually no HC in the report
New 02 sensor
New CTS
Cat is not the problem.
An associate said to wire in a 50 ohm resistor to the CTS circuit, The car passed but the readings are still telling me the car is running too lean.
What would be the best way to get it back into the appropriate range for proper operation?
The metering screw on the AFM?

I first tested it with a 179 ECU, both the 150 & 179 are giving similar readings with the only difference being the resistor hack.

Thanks for the assistance in advance.