03-23-2019, 07:51 AM
Very in-depth explanation about the function of an oxigen sensor in an engine, long and short term fuel trims and reset purpose.
https://www.youtube.com/watch?v=oRX2V6_a3dc
This video finally made clear to me how an oxigen sensor works and why it's output produces a variable wave instead of a straight line graph.
In short; the sensor operates within a narrow band and measures the exhaust gas, tells the ecm if the value is too rich or too lean and tries to keep the optimum stoichiometric air/fuel ratio at 14:1.
The ecm then adjusts the short term a/f ratio to maintain this value which is important for the functioning of the catalytic converter.
Over time the ecm learns this trend and produces an internal "map" of values for various engine speeds and other inputs, this is called "long term fuel trim" and is stored in memory to provide a base line for a/f control.
If there is a fault in the fuel system ( vacuum leak ) the ecm re-learns the "map" and changes some values in it, once the fault has been repaired these "wrong" values need to be reset by disconnecting the battery for 10 minutes which does a reset and then re learns a new set over time.( not sure about this but a good possibility )
This may be important info for the ones that remove the battery from the bike for storage!
As i am not knowledgeable enough to give any advice, may well be wrong in what i just stated and may not relate to our bikes i want you to not rely on my explanation, however there may be some info here that explains IF there is some unexplainable subtle behavior change with battery replacement.
Not trying to panic anyone, nothing is wrong, just some careful subtle advice with a little back ground.
If there is a better or more correct explanation out there i am sure we would like to hear it.
https://www.youtube.com/watch?v=oRX2V6_a3dc
This video finally made clear to me how an oxigen sensor works and why it's output produces a variable wave instead of a straight line graph.
In short; the sensor operates within a narrow band and measures the exhaust gas, tells the ecm if the value is too rich or too lean and tries to keep the optimum stoichiometric air/fuel ratio at 14:1.
The ecm then adjusts the short term a/f ratio to maintain this value which is important for the functioning of the catalytic converter.
Over time the ecm learns this trend and produces an internal "map" of values for various engine speeds and other inputs, this is called "long term fuel trim" and is stored in memory to provide a base line for a/f control.
If there is a fault in the fuel system ( vacuum leak ) the ecm re-learns the "map" and changes some values in it, once the fault has been repaired these "wrong" values need to be reset by disconnecting the battery for 10 minutes which does a reset and then re learns a new set over time.( not sure about this but a good possibility )
This may be important info for the ones that remove the battery from the bike for storage!
As i am not knowledgeable enough to give any advice, may well be wrong in what i just stated and may not relate to our bikes i want you to not rely on my explanation, however there may be some info here that explains IF there is some unexplainable subtle behavior change with battery replacement.
Not trying to panic anyone, nothing is wrong, just some careful subtle advice with a little back ground.
If there is a better or more correct explanation out there i am sure we would like to hear it.