The Oxygen Sensor determines the air/fuel ratio (AFR) of the engine by reading the hot gases in the exhaust system. O2 sensor can be one of two types. There is a narrow band (NBO2) sensor that is only able to accurately determine a vary narrow range of AFR’s. This is the type of sensor found on the majority of vehicles on the road today, but is not suitable for high performance work. The second type of O2 sensor is a wide band (WBO2) or UEGO (universal exhaust gas oxygen). This type of sensor is able to accurately determine AFR over a very wide operating range. These O2 sensors are suitable for use in high performance EFI engines. The newer ‘self learning’, no tuning required aftermarket EFI systems use this type of O2 sensor.

• Holley Efi Knock Sensor

It’s a piezoelectric automotive sensor that produces a small voltage signal when it hears internal engine noise that we often call knock and ping. This is why the location of the two sensors is a problem. In order to hear the engine noise reliably the sensors are buried under the intake manifold. Add this board to your MegaSquirt-III for knock feedback! This knock module can also be used with tuned knock sensors if they are tuned to your engine's bore.

Holley Efi Knock Sensor

When an EFI system is operating in 'closed loop' mode, it uses an O2 sensor to maintain the most efficient fuel mixture for reduced emissions and fuel mileage. While O2 sensor are currently rare on motorcycle EFI systems, governmental regulations for reduced emissions may result in more engines with these sensors on them in the future. All 2007 Harley-Davidson's use NBO2 sensors in closed loop operation mode.