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Bobd

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I am slowly developing
a relationship with MyEcu.

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O2 Flags
08/28/12 at 00:50:09

OK, I need a bit of help understanding the 'flags'.

I understand the MyEcu running closed loop uses the lamda sensor to detect how much oxygen is left in the exhaust gasses and that too much oxygen indicates too weak a mixture as we have not had enough fuel to react with the remaining oxygen, we can get more power by adding fuel to utilise this available O2. The MyEcu adjusts the fuel automatically to keep near the ideal air/fuelmix (providing the map is reasonably accurate.

In the Map we state what voltages from the lamda sensor equate to which air/fuel ratio. We then have the 'flags' table telling the MyEcu which particular ratio we want for each cell.

What I don't understand is how we assign the flag numbers, how do we know what air/fuel ratio we want for each cell?

Obviously as we have differing flag values we are not just setting it at the stiometric ideal. It seems we very accurately get the fuel system to inject an amount of fuel based on rpm, throttle, air pressure etc but then introduce these flag settings.

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YaBB Administrator YaBB Administrator Offline I love YaBB! Posts: 679 The Land of YaBB	Re: O2 Flags Reply #1 - 08/28/12 at 07:17:32 Have a look at this page for an explanation of the map - http://www.cajinnovations.com/MyECU/maps.htm Basically you have an array of 8 voltage targets, the index into this array is [0-7]. The flags table contains the index for that cell. so if your flags to O3 you will be selecting the 4th entry in the targets table.
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Bobd Full Member Offline I am slowly developing a relationship with MyEcu. Posts: 150 Southampton Gender:	Re: O2 Flags Reply #2 - 08/28/12 at 07:22:09 Yes, I have read that. How do you know which value to select?
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YaBB Administrator YaBB Administrator Offline I love YaBB! Posts: 679 The Land of YaBB	Re: O2 Flags Reply #3 - 08/28/12 at 07:31:28 That's what you need to determine. I don't have the data for the sensor and you can basically use what ever sensor you want. The base map you have has reasonable values from my Breva as a start. Modify as you see fit.
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Bobd

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I am slowly developing
a relationship with MyEcu.

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Southampton
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Re: O2 Flags
Reply #4 - 08/28/12 at 07:43:24

At the moment I am using the SPORT.ECU map set +5% across the whole map with a running TPS of 101 (95 with the engine stopped). The bike runs well, a bit slow to start but great in the mid range.

Is it the case that one either alters the map in an experimental fashion to get good running or use the Optimiser with closed loop and Autotune again setting the O2 targets experimentaly.

On the last fairly long run the Optimiser did not make any changes to the map in Autotune. Am I wrong in thinking it will update automatically if it finds itself in a steady 'Mon' state or do I have to tell it to save the change - a bit risky while riding. At the end of the run I just turned off the bike ignition, should I have exited Autotune before stopping the bike?

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Luhbo

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I Like My15M!

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Re: O2 Flags
Reply #5 - 08/28/12 at 07:44:10

I think you're asking what value is good for driveability or for power and in what range/cell, aren't you?
In that case: wellcome to an endless playground

Theoretically you can choose from L=1.2 for best economics down to L=0.8 for best power. Log your driving to see how you drive, where in the map you are doing what, and then guess where you need best power and where you can try to reach better efficiency.
I started with L=0.93 for the entire map, tried one similar with 0.96, actually I have one with values from .89 to 1.0 - all in all with very similar results. Maybe that next week I'l try one real rich, maybe not. That's why I have this unit instead of the Weber 15M.

Start with one of the given example maps in the download section for instance and look how these contributors dealt with this question.

In this context it would be a real 'nice to have' if we could switch via Optimiser for instance between 2 maps at least. This would make 'playing' a bit easier and more straight Wink

. But how said a German BMW/Mini commercial once (in English): 'Pussies Go Straight!' It gave a little trouble then as most people translated 'Pussies' differently Grin

Hubert

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« Last Edit: 08/28/12 at 07:44:57 by Luhbo »

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YaBB Administrator YaBB Administrator Offline I love YaBB! Posts: 679 The Land of YaBB	Re: O2 Flags Reply #6 - 08/28/12 at 07:48:00 My Sport map is set for an LC1 and would be totally inappropriate for the standard Guzzi sensor. You should take the tables from me Breva map. If that's what you have you're lucky the optimiser did nothing. You have to make sure the bike is running correctly with closed loop first before trying autotune.
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Bobd Full Member Offline I am slowly developing a relationship with MyEcu. Posts: 150 Southampton Gender:	Re: O2 Flags Reply #7 - 08/28/12 at 07:54:16 I used the Breva voltage settings you kindly sent me a few weeks ago. I suppose what I don't understand is how you decide what target lamda you are looking for in each cell. I imagine this is a general EFI matter rather that MyEcu specific.
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sign216

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Re: O2 Flags
Reply #8 - 08/28/12 at 23:10:04

Bobd wrote on 08/28/12 at 07:54:16:

I suppose what I don't understand is how you decide what target lamda you are looking for in each cell.

It's a little like asking what beer is best. Everyone has a different idea what's best for their specific bike, regional fuel variations, and riding style.

Tuning on a dyno could give objective numbers and end the argument, but most of us merely fiddle away, tweaking the map to reach some kind of perfection.

Joe

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Bobd Full Member Offline I am slowly developing a relationship with MyEcu. Posts: 150 Southampton Gender:	Re: O2 Flags Reply #9 - 08/28/12 at 23:39:58 Yes, a dyno is the answer but I need to fully understand what is happening first. In the old days we just tinkered with the carb to get a nice spark plug colour - I suppose we are now *telling* the ECU what colour we want.
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sign216 Full Member Offline Posts: 176	Re: O2 Flags Reply #10 - 08/29/12 at 11:18:05 Bobd wrote on 08/28/12 at 23:39:58: I need to fully understand what is happening first. A lack of understanding never stopped me.
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YaBB Administrator YaBB Administrator Offline I love YaBB! Posts: 679 The Land of YaBB	Re: O2 Flags Reply #11 - 08/29/12 at 13:30:37 The biggest mistake people make is changing something to what they think it should be with no other reason. Always let the symptoms of the bike drive the changes.
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