MoTeC AFM1 - Manual (Page 10)

6 Meter Operation
The display codes are as follows :
LA Lambda
AF P Petrol Air Fuel Ratio
AF A Alcohol Air Fuel Ratio
AF g Gas Air Fuel Ratio
AF d Diesel Air Fuel Ratio
Engine Tuning
The desired Air Fuel Ratio (or Lambda) is dependant on the tuning objective
i.e. Power, Economy or Emissions.
Normally at Full Load the Engine is tuned for maximum power and at light
loads the engine is tuned for emissions or economy.
The following table gives a guide to the required Lambda values for different
tuning objectives.
Objective Lambda
Power 0.84 to 0.90
Economy 1.05
Emissions 1.00
Note The exact requirements for a specific engine and fuel must be found by
experimentation.
Note On Turbo Engines extra fuel may be desirable to reduce exhaust
temperatures and help avoid knock.
Operating Tips
If the Engine misses for any reason including an over-rich mixture the Meter
may falsely read Lean. This is due to excess air being present in the exhaust
gasses which is caused by incomplete combustion when the engine misses.
Engines with high overlap cams running at low speed may pump air through
the engine resulting in a false lean reading, therefore the meter may need to
read richer than would otherwise be expected.