Computer re-set with aftermarket pipes/air filter

[53driver]

SRT-8,
I understand your post below - got it, no sweat. Thanks!

So.....what does the ECM "reset" function do?
And why/when would I do it?

My question got lost in the works here.....

If the mapping is all the same and nothing changes, why/when would this procedure be accomplished?

[srt8-in-largo]

Sorry about that! Yes the mapping is still the same and the points on the map being used get adjusted (slightly) by changes sensed by the correction and control sensors. A reset will not hurt anything, but after only a change of exhaust and an ECM reset, the map points will re-converge to the same place as if a reset was not performed at all.

A reset should be performed if a new ECM is installed or if any sensors have been replaced. A new sensor will behave a little differently than, for example, an oxygen sensor that has 100,000 miles of carbon build up on it. Or if a sensor has been slowly failing over time, this may cause the mapping to diverge to a set of map points that will be quite different from where a fresh sensor will point to. Resetting the ECM will put it in a known and tested "safe" location; not resetting when replacing sensors could result in a rough running bike until enough cycles have been run for the corrections to fix things.

A great example for all of this is how the engine uses the barometric pressure sensor. Oxygen content in the air that the engine breathes is very different at sea level and at high altitudes. These differences affect air-fuel ratio (AFR) and, in turn, that affects performance, fuel economy, and emissions. The baro sensor causes mapping corrections that maintain the right AFR wherever in the world you may be riding.

[srt8-in-largo]

Just to clarify my position, even though I believe a reset is not mandatory, I think a vendor is 100% correct to do this after an exhaust change. It's nothing more than a safety procedure to make sure the bike has zero chance of rough running until the sensors get used to the mod.

[53driver]

Sorry about that! Yes the mapping is still the same and the points on the map being used get adjusted (slightly) by changes sensed by the correction and control sensors. A reset will not hurt anything, but after only a change of exhaust and an ECM reset, the map points will re-converge to the same place as if a reset was not performed at all.

A reset should be performed if a new ECM is installed or if any sensors have been replaced. A new sensor will behave a little differently than, for example, an oxygen sensor that has 100,000 miles of carbon build up on it. Or if a sensor has been slowly failing over time, this may cause the mapping to diverge to a set of map points that will be quite different from where a fresh sensor will point to. Resetting the ECM will put it in a known and tested "safe" location; not resetting when replacing sensors could result in a rough running bike until enough cycles have been run for the corrections to fix things.

A great example for all of this is how the engine uses the barometric pressure sensor. Oxygen content in the air that the engine breathes is very different at sea level and at high altitudes. These differences affect air-fuel ratio (AFR) and, in turn, that affects performance, fuel economy, and emissions. The baro sensor causes mapping corrections that maintain the right AFR wherever in the world you may be riding.

Thanks. No apologies necessary. I was just confused on what this actually did - new components of the ECM stock is logical.

[CoCoKola]

Thanks. No apologies necessary. I was just confused on what this actually did - new components of the ECM stock is logical.

Interesting read all. I have a computer background, so the way i interpret what I'm reading is there is a procedure that, if it meets a criteria set by the manufacture, will set thresholds stored in rewritable memory for certain sensors used to make decisions. For example, low and high limits from an o2 sensor. These are used to 'calibrate' a cold engine from a hot one. These low high limits are then used for a look up on a 3d table created by mother honda that sets air / fuel mixture points based on the various sensors during subsequent use of the engine. Example, a new o2 sensor is installed.

Does this sound fairly accurate?

[53driver]

Interesting read all. I have a computer background, so the way i interpret what I'm reading is there is a procedure that, if it meets a criteria set by the manufacture, will set thresholds stored in rewritable memory for certain sensors used to make decisions. For example, low and high limits from an o2 sensor. These are used to 'calibrate' a cold engine from a hot one. These low high limits are then used for a look up on a 3d table created by mother honda that sets air / fuel mixture points based on the various sensors during subsequent use of the engine. Example, a new o2 sensor is installed.

Does this sound fairly accurate?

Yes.