Do the ECUs self correct?

[lavrgs]

I was wondering if the ECU is smart enough to adjust for changes to the exhaust system. I ask because after a couple hundred miles my Lemans, which I added a Mistral crossover to, seems to run better that it did just after the install.

[Dan M]

2002 LeMans does not have a closed loop system. There needs to be an oxygen sensor in the exhaust stream to give feedback to the ECM in order to make mixture corrections.

[luhbo]

2002 LeMans does not have a closed loop system. There needs to be an oxygen sensor in the exhaust stream to give feedback to the ECM in order to make mixture corrections.

 

Closed loop or not, narrow band sensors switch at lambda=1 and this is not the best value for driveability and power output, so there is probably no autocorrection function implemented. It can't work.

 

Hubert

[GuzziMoto]

It can work. It works very well on Buells. It does not work at all on Guzzis with no O2 sensor and it works fair on new Guzzis like the Griso and Breva in that it corrects the fuelling. But since the fuelling was not set well from the get go, it only returns it to the original target value, or as near that as it can get. Not to slam my Guzzi but that's one area that Buell has up on most others.

[luhbo]

The bikes you mention, have they wideband sensors fitted? Probably not. A standard sensor will not allow an optimisation of the maps. They don't deliver the signal an ecu would need for such a purpose. All they know is rich or lean, nothing technically usable inbetween. Also they are not at all fast enough.

 

All these probes can do is to keep the AFR around 14.7 and this only under certain conditions.

 

Do you know what type of sensor the bikes you've mentioned use?

 

Hubert

[Dan M]

The bikes you mention, have they wideband sensors fitted? Probably not. A standard sensor will not allow an optimisation of the maps. They don't deliver the signal an ecu would need for such a purpose. All they know is rich or lean, nothing technically usable inbetween. Also they are not at all fast enough.

 

All these probes can do is to keep the AFR around 14.7 and this only under certain conditions.

 

Do you know what type of sensor the bikes you've mentioned use?

 

Hubert

 

Under most circumstances, I think most of us would be pretty happy getting in the ballpark of 14.7:1 on a non feedback MG.

 

A modern closed loop system (which the 2002 LeMans does not have) not only uses oxygen sensors to control mixtures at a given time, but data from air flow, manifold pressure, altitude, intake air temp, coolant temp (if any), RPM, throttle position and a knock sensor. It not only alters fuel injector pulse width but ignition timing as well. It is far more accurate than what the 02 LeMans has.

[luhbo]

Yes, Dan, a modern system can do such things, especially in cars that are operated most of the time in a more or less static load and rpm range.

[GuzziMoto]

I am not an expert on Buell F.I., but this is what I've experienced and been told. As stated, the F.I. system uses not only the O2 sensor but also air temp, air pressure, engine temp, etc. to decide how much fuel to add. The main time the O2 sensor comes into play is under lower load, lower RPM use.The system goes mainly off a fixed map under high load. But that fixed map can be skewed up or down depending on what the O2 sensor is telling the system when it's being used. Thus, if you swap out the stock pipe for a free flowing aftermarket one, the system will adjust the fuelling accordingly. It's not exact and it's not perfect but it does work well. Far better then my Wifes V11 works( in fairness her bike works better then most Jap injection systems).It does depend on the base map being right to begin with and that is where my Griso comes up short. My old Buells F.I. was much better.