Idle                                                  Partial Open Throttle

The toggling speed of the meters are a good approximation of my 84 Porsche 944. You will notice that the toggling is much slower when the car is idling, faster at part throttle. At wide open throttle (WOT), the O2 sensor is not used by the DME, there will be no toggling and the meter will show full rich.

You will notice that the air/fuel ratio never stops at the ideal of 14.7. The air/fuel ratio is constantly jumping between a little rich and a little lean. It always stops on the rich side, or lean side, of the ideal ratio.

Important note: When adding a meter, always splice into the O2 sensor's wiring. Never splice into the main wiring harness. The harness is made of shielded coax cable and it is not anything you want to splice into. Never solder the O2 sensor wiring but use butt connectors or the new posi-lock (waterproof) connectors instead.