405 L4-1905cc 1.9L (1989)
Air/Fuel Mixture: Adjustments
The air fuel mixture at idle is not adjustable. It is adapted automatically by the ECU based on input from the Oxygen Sensor. On-Board Diagnostics
continually check the richness adaptation which is done by the ECU. Error code 51 will be set and the "CHECK ENGINE" indicator will illuminate if a
fault with this system is detected.