B3701 not updating when i save... Please help....

[BlackGMC]

I just tried to update these values

LABELS Battery Volts {link: GM.VOLTS}
Manifold Vacuum kPa {link: GM.MANVAC} 14.0
0 0.077333
5 0.077333
10 0.077333
15 0.061867
20 0.061867
25 0.061867
30 0.061867
35 0.061867
40 0.061867
45 0.061867
50 0.061867
55 0.061867
60 0.061867
65 0.077333
70 0.077333
75 0.077333
80 0.077333

I tried 1%, 2%, 3%, 4%, 5%, 7%, 10%, 11%, nothing ever happened. Then on 13% it looked like this when i saved it

LABELS Battery Volts {link: GM.VOLTS}
Manifold Vacuum kPa {link: GM.MANVAC} 14.0
0 0.077333
5 0.077333
10 0.077333
15 0.069909
20 0.069909
25 0.069909
30 0.069909
35 0.069909
40 0.069909
45 0.069909
50 0.069909
55 0.069909
60 0.069909
65 0.077333
70 0.077333
75 0.077333
80 0.077333

Then after i closed it and reopened it it looked like this

LABELS Battery Volts {link: GM.VOLTS}
Manifold Vacuum kPa {link: GM.MANVAC} 14.0
0 0.077333
5 0.077333
10 0.077333
15 0.077333
20 0.077333
25 0.077333
30 0.077333
35 0.077333
40 0.077333
45 0.077333
50 0.077333
55 0.077333
60 0.077333
65 0.077333
70 0.077333
75 0.077333
80 0.077333



I am only trying to update the 0.061867 value....


seriously i am not crazy even thou it appears that way...

[joecar]

Post your before and after files here, please.

[BlackGMC]

I can post them tonight, i don't efi live on my work laptop :(

[joecar]

ok.

[Blacky]

The LS1 PCM (and most* vehicle controllers) are calibrated using integers (i.e. whole numbers) to reduce the cost and processing load on the CPU.
High precision floating-point values require dedicated hardware (more expensive) or software floating-point routines which slow down calculations.

* Note: Later model controllers use CPUs with built in floating point hardware and they do make limited use of high precision floating point data.

Storing calibration data as integers like the LS1 PCM does, allows only a discreet set of scaled floating point values.
For example if the PCM requires a table to contain data from 0.00-100.00 (for example throttle percentage) using only the set of integers from 0..255 (i.e. a single byte) then it would scale that set of integers by dividing each one by 2.55.
That would mean the following conversion would be in effect:
0 = 0.0
1 = 0.392157
2 = 0.784314
...
245 = 99.607843
255 = 100.0

As you can see, if the PCM can only store the values from 0..255, then when it has a 1 stored the PCM will interpret it as 0.392157, when it has a 2 stored the PCM will interpret it as 0.784314.
Since it is impossible to store an integer value between 1 and 2, which means it is also impossible to represent any value between the two discreet values: 0.392157 and 0.784314.

What you are seeing in the B3701 table is the effect of the limits of the integer to floating point scaling that I described above - just with different scaling.
The EFILive tuning software allows the user to enter full precision floating point values. It has to do that to preserve as much precision as possible while the user is editing/manipulating the data. Because of that you can enter any floating point value that you want into the tables. When the data is saved back to the tune file, the software must convert the final floating point values back to their nearest scaled integer values that the PCM requires.

There is no way to calibrate any values between the two values (0.061867 and 0.077333) that you are seeing. Its either one or the other.

Regards
Paul

[BlackGMC]

Thanks for the respone Paul, i appreciate it. Yesterday it was driving me crazy...