IHADAV8.com - Turbo Buick Tech, and Nonsense
Tech Area => General Buick Tech => Topic started by: daveismissing on April 03 2013, 08:11:36 PM
-
Somebody suggested that the BL's cannot go below about 105?.
Is that correct?
Since the register can contain a value from 0-255 I find that answer suspicious?
D
-
http://www.gnttype.org/techarea/faq/BLMINT.html (http://www.gnttype.org/techarea/faq/BLMINT.html)
-
So outside of that range the ECM gives up?
Or thats the maximum amount of correction its programmed to apply?
-
I swear that I have seen blms in the 90s but I am probably wrong...I have seen others quote Dave's write up as the bottom limit before
-
So outside of that range the ECM gives up?
Or thats the maximum amount of correction its programmed to apply?
They are the hard limits for the ECM to adjust to. They are a trim percentage.
-
Both the BL and INT values are limited by programmable values set by the chip maker. The stock INT limits are 100 and 150. If the INT value goes beyond one of the limits during C/L corrections, the INT value is clamped at the limit value and life goes on.
The stock BL limits are 105 and 150. After a C/L fuel correction is calculated, the BL min/max values are treated the same as with INT. Before writing (storing) a newly calculated BL value, it is clamped to the limit value. Now, if the ecm ever reads a BL value from memory that exceeds either the min or max value it will reset all the BL cells to 128. Since the BL value cannot exceed the min/max during a BLM write, reading a BL value beyond min/max indicates a corrupted number which is why the BL cells are reset.
[size=0pt]As for the percentage of correction, a value of 150 produces a 17% increase in fuel over the ideal 128 value. [/size]A value of 105 reduces the fuel by 18%.