Wow, this is sweet. My 94170015 has:

low > mid 56.25hz
mid > low 43.75hz

Why is there such a window between them? Shouldn't it be for example low>mid 56.25 and mid>low 55 or 50 or so?

 

There is an adjacent table at @3025 for 88590015 which controls RPM,
values are taken depending on the same variable.
Mattjin can you comment on that one too?

<table name="Closed Loop - RPM Control???" category="Fuel" address="3025" type="2D" level="2" scaling="RPM">
<table name="Conditions" type="Static Y Axis" elements="4">
<data>1</data>
<data>2</data>
<data>3</data>
<data>4</data>
</table>
</table>

 

That is the main RPM table I have been talking about, but I have been reluctant to display it yet until I know for certain what the rpm numbers reflect. It is simply the next four numbers after the Hz table. This uses RPMStatLimit as its scale, but it requires a new scaling in unit8 rather than unit16. You can add this scale line to your xml

<scaling name="RPMStatLimit8" units="RPM" toexpr="x*31.25" frexpr="x/31.25" format="%.0f" min="0" max="9000" inc="1" storagetype="uint8" endian="big"/>

You can then add Acamus' map from above but change the scale type to this.

To get the Airflow scaling forumula I simply divided 1600hz by 256, but considered that we need 0Hz so the max is actually 1593.75 and having roughly 6Hz per adjustment +/- I figured the fractions dont really have much of a real world effect. Maybe Acamus can dig into the code and see which one it truly is, but either way the biggest thing is that this function is now adjustable.

These were the other maps related to the LT trim in my rom.

80700010:

<table name="Closed Loop - LT Trim RPM Limit" category="Fuel" address="17e2" type="1D" level="2" scaling="RPMStatLimit"/>

<table name="Closed Loop - LT Trim Volts High" category="Fuel" address="17e6" type="1D" level="2" scaling="BatteryVoltage"/>

<table name="Closed Loop - LT Trim Volts Low" category="Fuel" address="17e8" type="1D" level="2" scaling="BatteryVoltage"/>

<table name="Closed Loop - LT Trim RPM" category="Fuel" address="3a1d" type="2D" level="2" scaling="RPMStatLimit8">
<table name="Conditions" type="Static Y Axis" elements="4">
<data>1</data>
<data>2</data>
<data>3</data>
<data>4</data>
</table>
</table>


There are two more 1D's related to the trim, but they are of unknown units. The only other subroutine I want to track down is to do with what triggers the LT trim to enable.

 

It is hysterisis and done to stop the wrong trim being effected. If they are too close together and you are sitting on the switch point you will start to get both trims moving around. For those with issues I would actually suggest increasing the hysterisis.

 

I looks like I just found something (I expected to find) that does not allow long term trim control whenever there is Purge duty. Useless for adjustment, but interesting to see.

 

Could it be possible that both RPM and Hz conditions must be met in order for the LTFT to start adjusting?

Got the address fot the RPM table for 94170015?

 

Just bare in mind that the function and scale for this map is not certain. It is RPM related and references MUT21 which is the RPM used for almost all 1D adjustments. The only difference being that all 1D's are in uint16 but the map is in uint8, which is the reason for the new scaling being needed from post#18.

For my rom I could make the trims work with Hz at idle regardless of the RPM settings. There might be an OR setup in there where if the rpm conditions are met it will switch trims whether the Hz conditions are met or not. I might check into that today, time allowing.

94170015:

<table name="Closed Loop - LT Trim RPM" category="Fuel" address="35e9" type="2D" level="2" scaling="RPSStatLimit8">
<table name="Conditions" type="Static Y Axis" elements="4">
<data>1</data>
<data>2</data>
<data>3</data>
<data>4</data>
</table>
</table>

 

Is there any reason not to make the scaling issue easier to distinguish and call it "Air Flow (trim) Hz" ... it would make sense to also call the other "Air Flow (MAF) Hz" but that one has been around a while and might be hard to get changed unless all the big boys agree and start doing it in everything they push out.

Just a thought [shrug].

 

scaling="RPSStatLimit8"

I need the full scaling to put in my XML to make this work.

Never mind....you made a slight typo

Should say scaling ="RPMStatLimit8"

 

The RPM values seem a little odd. They seems too high. Are they backwards?

I have

1 1406
2 1344
3 1094
4 1031

 

That is exactly why I didnt post it earlier, because it will only cause confusion. The numbers are correct, but what they represent is anyone's guess at the moment.


I will edit the first post and rename the maps and scale. That scale name was not in my rom because I dont inherit and base files.



*** EDIT : Renamed the scale to "LT Trim Hz" and it is advised that everyone do the same for continuity.

 

Are you certain the value should be an RPM and not a LOAD?

Or since they are a little odd....might they be timing instead of RPM?

 

Thanks for the Re-name idea.....makes life much easier.

 

Great job Matt

 

Since values in the RPM table are compared with MUT 21 it shall reflect RPM in some manner. There is no comparison with load.