GTM Fueling Info

[MMV9]

Hi

This thread starts from 2009 and my post the other day that was deleted with a re-direction to here was based on the 2021 ECU update by MG for the V7 V9 that implied the fuel mix would adjust according to the lambda air mixture. Is this 15 year old post still gospel in most peoples' opinion?

Mat

 

[scottmastrocinque]

This is the very simplistic explanation.

There is nothing more misunderstood and riddled with false information, than common belief of what an O2 sensor does, and how.

Readers Digest version: O2 sensors do one thing and one thing only. They attempt to get the engine to run in the theoretically perfect AFR of 14.7 : 1 ratio. This is all they do. They ARE ONLY ABOUT EMISSIONS AND DO NOTHING WHATSOEVER FOR OPTIMIZING RUNNING. PERIOD.

In OPEN loop operation, the ECU utilizes the F.I. table only. It uses the hard value coded into the table and values from the air and temperature sensors.

In Closed loop operation, the O2 sensors completely disable the Fuel Injection Table in the ECU, and begin a constant hunt for this 14,7: 1 ratio.

This is the only goal and function of an O2 sensor.

In the case of a “narrow band sensor”, this has the ability to make “Closed Loop 02 correction” to fueling to try and reach this 14.7 : 1 ratio if the variance from this target value, is narrorily rich or lean from the target value.

If the “read” value of the O2 sensor is outside of this narrow range, the ECU just ignores any data until the time the read value comes back within the sensors diagnostic range of operation, whereupon it resumes making extremely small adjustments again.

Wide band sensors, have the same ability, but they can effect the “Closed Loop O2 correction” across a wider range from the 14.7 : 1 target ratio.

If the wide band sensor reads values outside its normal range, it does the exact same thing as the narrow band sensor I described above as well.

This is why the GTM fueling solutions work so well, they first start with a much better and optimized base map.

Additionally they utilize wide band sensors to try and effect correction across a wider range of read values.

Finally, the Autotune is integrated in concert with the PowerCommander to create the most advanced fuel modification solution with fully dynamic modification and on the fly programmable target values that can be used on a motorcycle.

The foundation of all of this is the customized base map that GTM crafts for you that gets downloaded by the GTM tool.

So yes, GTM’s statements on this product can be considered gospel.

 

[Hurk51]

Great explanation Scott!
I have noticed on my 2021 Euro 5 V85TT when i am reading "Live data" with my tool and i go into closed loop i do not get steady fuel numbers on both cylinders until i hit 3500 rpm with the stock fuelling map that Guzzi has installed. This seems to correspond with people doing reviews on the internet of the bike when it came out that " it likes to rev" comments and it also corresponds to what i have seen on spark plug conditions for fuelling. You can also see the results of this 3500 rpm in the live fuel usage/ fuel mileage readout on the bikes TFT display. Guzzi wants the bike to rev higher so that the cat converter is in its optimum range for burning unburnt fuel and the O2 sensors seem to like that rpm as well to control in the band they were designed for IMO. What is interesting in the live data on the stock map is when you look at the fuelling of each O2 sensor below 3500 rpm the fuelling is not balanced cyl to cyl. One cyl is running very rich compared the other.

 

[V700Steve]

Fueling engineers at MG are not the best, they should find some better ones.

 

[MMV9]

Fueling engineers at MG are not the best, they should find some better ones.

I think it's the curse of air cooled engines and Euro 5 compliance, Euro 5+ will probably be worse. BMW manage with their air cooled twins but they've way bigger development budgets.

 

[scottmastrocinque]

Fueling engineers at MG are not the best, they should find some better ones.

How long will these terrible myths persist?

Moto Guzzi has been part of the Piaggio Group since 2004.

Two Thousand and four. That’s 20 years.

Aprilia, is also one of Piaggio Group’s marques.

“In 2022, Aprilia experienced impressive growth in terms of results (their first MotoGP win, another eight podium finishes, and two pole positions) which placed the Italian team among the championship protagonists, in the battle all the way to the end of the season for the most prestigious objectives in every category.”

They have brilliant fueling engineers. Some of the very best in the world.

What causes the problems are the insane EU regulations which are borderline capricious in their rigidity and application against the manufacturers.