Lambda Sensor – Wideband vs Narrowband. The Difference?
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Wideband lambda sensors measure the air fuel ratio (AFR) of the engine over a “wide” range (around 10:1 to 22:1 AFR).
Narrowband sensors only measure the AFR accurately around 14.7:1.
Narrowband sensors are more of a switch, either the mixture is 14.7 or it richer, or it’s leaner, it won’t tell us by how much.
Narrowband lambda sensors are good for measuring air fuel ratios at idle and light cruise conditions only. In conditions where we are using more load, running the engine at 14.7:1 is usually not ideal for power or fuel economy. Because the narrowband sensor can only measure accurately around the 14.7 ratio, it’s not suitable for measuring AFRs when the engine is under load. This is where a wideband lambda sensor comes in.
It can be helpful for power and emissions to be able to know what the air fuel ratio is under all load conditions. A wideband can also tell us if there are potential air fuel ratio issues with the engine and if so how bad the issue is. And depending on the issue, a wideband lambda sensor can allow the ECU to adapt and run the engine optimally, even if a component has a problem.
Generally the world (OEM and aftermarket) have moved towards using wideband lambda sensors.
More power, more of the time, with better fuel economy and better reliability.
