Short-term Long Term Fuel Trim (LTFT)?

[ViperGeek]

Vehicle: 2010 Dodge Challenger SRT8 w/stroked 426cu-in HEMI and 2.8L Kenne Bell S/C at 12PSI

I recently graduated from a DiabloSport Trinity to HP Tuners VCM Suite and I couldn't be happier. While I get a feel for the new capabilities, I've been performing data logging with VCM Scanner while driving around town. What I seem to have noticed is that the Long Term Fuel Trim (LTFT) table is quite incomplete, when compared to driving around with the Trinity displaying LTFT1/LTFT2. The Trinity is showing lean trims as deep as -20% while VCM Scanner shows trims in the range of -1 to -9% (see attached).

In a related puzzlement (that clearly shows I don't understand what I'm looking at), it seems my VCM Scanner log only shows maybe 30 cells as non-zero or non-blank, yet the Trinity has many, many more combinations of MAP and RPM showing non-zero trims while driving.

Is the VCM Scanner showing me the current complete table of LTFT values, or only those matched during the data logging? In other words, if during my logging, I never reach 50kPa at 3600RPM, will the resultant log file show a blank cell, even if the PCM has a value stored for that combination?

If my SWAGs are true, is there any way to dump the entire stored table of LTFT values?

Thanks!

- Dave

[dermotw]

Presumably you created your own LTFT table to look at that, and of course for a start there are a bunch of settings to play with, for example average vs. max values, usually by default HPT is looking at the average in a cell. Also thers the cell hit count, often low hit counts are ignored, of course you can change that...

But to get to the point, I don't <think> that HPT will show any "default" values that might exist in cells you don't hit. But I'm no expert...

-d

[dermotw]

Heres your file viewed with a table I use;

ltft1.JPG

ltft2.JPG

There are a lot more than 30 hits in that...?

-d

[ViperGeek]

Thanks very much for the replies.

Your table looks like exactly what I was hoping to see. As you suspected, I'm using the default view using (A)verage LTFT:

LTFT.jpg

May I ask the settings you used to obtain the much more informational table of trim values?

- Dave