V7 Map & 02 questions

[usedtobefast]

Hopefully this is an OK place to post my questions.

Do the maps for the V7 III turn off the O2 sensors (or rather, just ignores them)? Or does it still use them?

If the maps do not use the O2 sensors, does it still handle significant altitude changes? Say riding from 1500 ft above sea level to 11,000 ft above sea level in the same day, I assume the FI will adjust the mixture so the bike runs well all the way up and back?

Sorry for my ignorance on this, just not sure how the FI makes that adjustment if it has no closed loop capabilities.

 

[Godfrey]

O2 sensors are on the header pipes. I have neither disconnected nor removed them in changing ECU maps, changing mufflers, or disabling the EVAP system.

My understanding: When you update the map, you reset adaptive operations so that it starts out at a null default and then builds a set of parameters that it stores to adjust dynamic running attributes. The EFI system has ambient temperature, ambient air pressure, intake tract air pressure, O2, throttle position, etc. sensors. O2 sensors generally provide trim adaptations to ensure the catalytic converter doesn't get too rich or lean a mixture, which can disable/damage it. That's kind of a similar function to the SAS system (adds additional air/oxygen AFTER the exhaust port when the mixture goes too rich to burn it off in the exhaust pipe), but the SAS system is designed to operate on large, fast changes that O2 sensors are too slow to respond to. They're both usually 100% emissions oriented, not altitude adjustment.

Altitude mixture adjustment is dependent upon air pressure, air temperature, and RPM to influence mixture and timing settings ... they're managed by measuring ambient air temp, ambient air pressure, manifold pressure, RPM, throttle demand, and load (which it knows by calculating the above against the current gear selected) and then adjusting according to the map's parameters.

I'm not sure if your terminology is correct. I've always considered a "closed loop" engine management system to be one in which the absolute values in the map were what all the sensors allowed the ECU to pick, and an "open loop" system to be one where another sensor ... usually an air mass sensor that reads the actual volume of air flowing through the intake tract ... constitutes an external input to establish the final values that the ECU uses according to a set of suggested relative targets in the map. Closed loop systems have a specific, defined maximum ranger of adjustments since all final parameter settings are contained in the map, where open loop systems have a response range that accommodates a wider range of environmental situations because the final results are calculated by reading the actual air volumes and calculating the mixture and ignition timing from that. But I might have my terms backwards as well, it's more a semantic question than a change in how a specific system operates.

There's a handbook for the Marelli ECU system in GT's downloads section.

 

[usedtobefast]

O2 sensors are on the header pipes. I have neither disconnected nor removed them in changing ECU maps, changing mufflers, or disabling the EVAP system.

Do you know if your map & ECU settings are paying attention to the O2 sensors? Could it just be ignoring them?

So a stock V7 III, going from 1500ft to 11,000ft would not use the O2 sensor info to adjust fueling? It would handle that using all sorts of other sensors? Again, ignorance here, but I would think having a sniffer in the exhaust header would be a wonderful source of data/info. Like sniff the exhaust, keep things around a 13.2 air/fuel ratio, same at various altitudes.

 

[GTM®]

This has been covered on this Forum ad nauseam, you just have to search and read.
Closed loop uses 02-sensors for correction. In the case of every Guzzi to date, it is narrow-band sensor that only crudely revises at lower speed throttle, to the programed lean emission burn target AFR (15-17.0+). When the input is deleted (open loop), the system relies on all of the other sensors in place for correction as Godfrey mentions above.
The real-time closed-loop system you speak of exists for every Guzzi EXCEPT the '13+ V7 as noted here; https://www.guzzitech.com/store/product/pc-vat200gt-rx-ecu-flash-tool/
Also see; https://www.guzzitech.com/forums/threads/guzzitech-power-commander-v-information.2686/

 

[Godfrey]

Thanks Todd!

As Todd implied, O2 sensors are generally not very good on response time and have a very narrow working range. Relying upon them for altitude mixture and timing adjustment is generally unwise.

BTW: I remember on high-performance slide-throttle carburetor bikes, like my old Ducati 750GT and LeMansV, I'd have to drop the needles a notch over 4000 ft or so, and drop the main jets down one size for every 3000 additional feet altitude or they'd start losing power from running too rich. Bikes with CV type carbs, since they essentially have a built-in air mass sensor in the form of the constant vacuum chamber that's controlling the main slide, are much less likely to need jetting changes until you get way high up.

Todays ECU driven bikes do most of this for you automatically, once you get the map correct. Fun fun fun ...