Injector Data "changing" after saving and reopening file.

[powerfreak]

Guys,

I'm having some issues plugging in injector data into a tune file. Quick rundown....We have a 2003 Silverado 2500 with a LQ4/4L80E setup. The engine is now 408 cu. in., LS3 heads, L92 escalade intake, LS3 injectors and a 87mm "truck" throttle body running a X-Link throttle body harness adapter. I have converted and plugged in all the LS3 injector data into the LS1B ECM. (12579405 OS) After I save the file and reopen it several calibrations change on their own...B4003, B4004, B4005, B4006, and even B4001 mysteriously change. If you give this truck any sudden throttle it will go dead lean and start popping bad out of the exhaust due to it being so lean. But I know I've got to get this file straightened out first before I start doing any kind of tuning/adjustments. Has anyone ever seen their injector data change when saving their file? Mainly B4005 (Small Pulse adjust) shows crazy numbers after you re-open the tune file. I've attached the tune showing the "changed" data. The data that is supposed to be in there is LS3 injector data. If you look at the file you can see it's nowhere close. Can anyone shed any light on this one?

[powerfreak]

Here's some more info so you can get a better idea of whats going on...

B4006-Small Pulse Threshold is set at 4.000000ms, when you save and re-open it is changed to 4.005867ms

B4003-Minimum IPW is set at 0.796875, after save file and re-open it's 0.804267

B4004-Default IPW is set the same as B4003, does the same thing when saved and re-opened.

B4005-Small Pulse Adjust is set as follows:

0.000000
0.299337
0.317581
0.281093
0.245132
0.201477
0.157935
0.114457
0.071164
0.043472
0.028150
0.009429
-0.001889
-0.013283
-0.024738
-0.034333
-0.042093
-0.047915
-0.051825
-0.051896
-0.048112
-0.048165
-0.052069
-0.054046
-0.054128
-0.052234
-0.048400
-0.046494
-0.046521
-0.046547
-0.046571
-0.046617
-0.046637
-0.044710
-0.040835
-0.038902
-0.038915
-0.038928
-0.038940
-0.038967
-0.038977
-0.037038
-0.033148
-0.029256
-0.025362
-0.025367
-0.029274
-0.031242
-0.031247
-0.029300
-0.025399
-0.021496
-0.017592
-0.017595
-0.021512
-0.023469
-0.023472
-0.023475
-0.023478
-0.023480
-0.023483
-0.021529
-0.017623
-0.015667
-0.015668
-0.015670
-0.015671

In the file if you look at B4005 you'll see what it has changed to. COMPLETELY different numbers!



B4001-Injector Flow Rate is set at :

5.257813
5.289367
5.320735
5.352102
5.383470
5.414837
5.446204
5.477572
5.508939
5.540306
5.571674
5.603041
5.634409
5.665776
5.697143
5.728511
5.759878

again, looking at the tune file numbers change for B4001 when its saved. It has done this (changed data) over and over. It even changed when i plugged those numbers into a fresh file from the tune depot. Any help or insight is greatly appreciated.

[joecar]

Those numbers changed 1% or less.

You're seeing discretization error... the binary format/reprsentation of those tables allows specific discrete values, any values in between 2 discreet (successive) values will be rounded to the closest.

[powerfreak]

Those numbers changed 1% or less.

You're seeing discretization error... the binary format/reprsentation of those tables allows specific discrete values, any values in between 2 discreet (successive) values will be rounded to the closest.

Thanks for the response and clearing that up joecar.

[joecar]

More info if you're interested:

some-fields-just-will-not-save
Wtttttfffffffffff!!!!!!!!!!!!!!!!