LTFC Cell Values

[Chuff]

I've just run the LTFCDL macro in the Holden VR and VS Commodore 5.0L V8 definition and download the LTFC Cell Values from the ECU in my car. I have a 5.0L VP Calais with a 1227165 ECU running a 16183082 $12 binary.

I've noticed that the definitions within EFILive V4 for the downloaded cells 1 to 20 coincide with RPM vs MAP values of 1200 to 3200 RPM and 30 to 70 kpa.

Does this mean that the values extracted via the LTFCDL specifically represent LTF corrections applied to the RPM/MAP values as detailed above? This seems like a rather restrictive dataset, as I would have thought that RPM & MAP intersection outside the scope mentioned above would also be included in any LTF calculations.

If I'm off the mark, then does anyone know if the data in the 20 cells downloaded by the LTFCDL macro can be used to correct the VE tables? If so, how?

Thanks.

[Chuff]

I've done some further analysis on some data I have gathered and have found that my original post cannot hold true. I have attached a summary of the Min & Max RPM & kpa values from my dataset for each LTFC Cell, and the values exceed the RPM & MAP figures as I have discussed. I would appreciate it if someone could please explain the MAP & RPM boundaries for each LTFC Cell.

Maybe I should explain what I am doing, and what I think I need to do.

I have modified readily available VE calculation software off the internet to work with the ECU\BIN combination I am using. I use this software and the data which I have logged and saved as a CSV file to recalculate the VE figures. So far, so good.

The other day while doing some data logging it occurred to me that the data I was logging was for both Closed & Open Loop Fueling Mode, as well as True & False Fuel Learn Status values. This got me wondering whether I should have only included logged data where Fueling Modes was Closed Loop and/or Fuel Learn Status was true. If someone could clarify which conditions represent the correct data to use in my VE re-calculations I would greatly appreciate it.

Based on this discovery, I now don't know how to proceed, as I can't export the Fueling Mode & Fuel Learn Status values to the CSV file in order to eliminate that data from the VE calculations, and when I download the LTFC Cell values the descriptions of what they represent seems incorrect, so I don't know what VE data requires changing.

I hope all of this makes sense.

Thanks for any help.

[joecar]

Chuff,

I pm'd Paul so he would see your questions.

Joe

[Chuff]

Thanks Joe.

[Blacky]

I've done some further analysis on some data I have gathered and have found that my original post cannot hold true. I have attached a summary of the Min & Max RPM & kpa values from my dataset for each LTFC Cell, and the values exceed the RPM & MAP figures as I have discussed. I would appreciate it if someone could please explain the MAP & RPM boundaries for each LTFC Cell.

Maybe I should explain what I am doing, and what I think I need to do.

I have modified readily available VE calculation software off the internet to work with the ECU\BIN combination I am using. I use this software and the data which I have logged and saved as a CSV file to recalculate the VE figures. So far, so good.

The other day while doing some data logging it occurred to me that the data I was logging was for both Closed & Open Loop Fueling Mode, as well as True & False Fuel Learn Status values. This got me wondering whether I should have only included logged data where Fueling Modes was Closed Loop and/or Fuel Learn Status was true. If someone could clarify which conditions represent the correct data to use in my VE re-calculations I would greatly appreciate it.

Based on this discovery, I now don't know how to proceed, as I can't export the Fueling Mode & Fuel Learn Status values to the CSV file in order to eliminate that data from the VE calculations, and when I download the LTFC Cell values the descriptions of what they represent seems incorrect, so I don't know what VE data requires changing.

I hope all of this makes sense.

Thanks for any help.

The PCM does not learn fuel trims in open loop, so if you can:
1. Force open loop all the time, or
2. Discard closed loop data.
Then you should have a reasonably good data set.

I did not realise that the flags were not being exported. I will look at adding them to the export list - that way you can use Excel to extract only the open loop data.

There is also another command to force open loop which I will try to include in the VS/VR *.xml file. That way you can create a macro that (hopefully) keeps the PCM in open loop.

If you don't hear back in this thread in a few days - remind me with another post.

Regards
Paul

[Chuff]

The PCM does not learn fuel trims in open loop, so if you can:
1. Force open loop all the time, or
2. Discard closed loop data.
Then you should have a reasonably good data set.

I did not realise that the flags were not being exported. I will look at adding them to the export list - that way you can use Excel to extract only the open loop data.

There is also another command to force open loop which I will try to include in the VS/VR *.xml file. That way you can create a macro that (hopefully) keeps the PCM in open loop.

If you don't hear back in this thread in a few days - remind me with another post.

Regards
Paul

Thanks Paul, look forward to the new XML file.

Could you just clarify what you have said as your use of Open & Closed Loop seems to be contradictory. Not being picky, I just want to make sure I understand.

Thanks.

[Blacky]

Sorry my bad, I've spent too long calibrating VE tables with EFILive V7 and a wide band O2 sensor. When doing it that way, the goal is to eliminate the fuel trims because they skew the data. To do that, you need the PCM running in open loop.

If you're using the LTFT data to calibrate the VE table then you're going to want to be in closed loop to collect/learn the fuel trims.

Once we get ALDL data logging into EFILive V7 you will be able to use EFIlive's "AutoVE" automatic calibration of your VE table using a wide band O2 sensor and the Commanded AFR value from the PCM.

Hopefully early next year

Regards
Paul

[Blacky]

Not sure if you're using the Pro or Eval version so I updated both:
http://68.178.219.18/software/EFILiv..._4_6_5_306.zip (830Kb)
http://68.178.219.18/software/EFILiv..._4_6_5_306.zip (830Kb)

Just copy the included *.exe file over the top of the existing *.exe file in the \Program Files\EFILive\V4 folder.
Please save the original *.exe first so you can restore it later if you need to.
Save the updated *.xml file into the folder where all the other vehicle stream definitions are stored.

Regards
Paul

[Chuff]

WOW, that was quick.

Thankyou very much.

[Chuff]

Hey Paul,

Sorry to bug you again but could you please clarify something for me.

I've attached some data that I have collected today. I collected this data using the new Open Loop command which you have provided, but from what I could see while monitoring EFILive while driving, I don't believe it stayed in Open Loop all the time. If you could tell me what values identify the rows I need to use in order to recalculate my VE values, I would greatly appreciate it.

Thanks.