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Oxygen sensor

2581 Views 4 Replies 5 Participants Last post by  nightrob
I hope you will not mind my question, since I need your inputs in order to understand the difference between the EFI bikes' exhaust systems (and the work of ECMs, engines) with oxygen sensors, and the older-style EFI bikes' exhaust systems (and the work of ECMs, engines) with NO oxygen sensors.

OK, oxygen sensor needs to determine the AFR by analyzing exhaust gases. Then, utilizing input from the sensors, the ECM's adjust fuel delivery to maintain factory-set AFR.

So, if we have O2 sensor, why we still need a DFO/Power Commander/SERT etc when we install after market parts (slip ons and high flow air filter)?

We also need a DFO/Power Commander/SERT on the bikes with no oxygen sensor, but with after market parts (slip ons, air filter) added. This is OK.

How come that older EFI bikes did not need/have the oxygen sensors? Is this just an improvement over the bikes with no oxygen sensors in order to enable better ECM and engine response?...I still don't get it.

Thank you very much for your comments.
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The sensors are only active in certain rpm and load ranges, particularly idle and cruise. When your work load is beyond that range, the sensors are inactive. This is the major difference between low band and wide band sensor systems.
This is my understanding.

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