There are many explanation such as fuel ratio, oxygen, and oxygen sensor are explained inside this installation instruction . In this installation instruction you can find info such as auto meter, sensor, and installation.
This installation instruction contains explanation about auto meter instruments, ratio monitor, and air fuel ratio. These are chosen from this installation instruction :
12V Ignition Switch 5 AMP Fuse d Re Black Good Engine Ground Re d et ge ol lta Vi Vo or ns Se Black Heater Ground ter + Hea Oxygen Sensor Warning Fouling and/or permanent damage to the oxygen sensor over time will result if used with any of the following: • Leaded gasoline and fuel additives containing lead • 2 cycle gasoline (gas/oil mix) • Diesel fuel • Nitromethane • Excessively rich mixtures If the air / fuel ratio monitor responds sluggish, the oxygen sensor is probably partially fouled, and should be replaced.
Additionally, the installation instruction contains info things like the oxygen sensor, and fuel ratio monitor.