Regarding the bpw calculations from Pablo...

First, what units is the bpw in, usec? If I used the value I calculated my motor would be extremely over-fueled unless I move the decimal place to the left one digit. In other words I have values that are working fairly well at nominal operating temps of 8-10 usec, not my calculated value of 98.66.

Second, does your ecm/pcm use the bpw as a global variable that scales the calculations made from the ve tables?

My questions depend from the fact that the $0D pcm has a temperature scaled table for bpw. Presumably (according to Tunercat) this value is used for startup. Do you know how the pw algorithm generates pw from the ve tables and how the block learn cell is incorporated to quantify load on the motor?

 

i posted to that other thread and one more thing to add, 8-10 bpw and your car would not run it would be so lean (stock bpw is 135)

 

I posted this in the other thread, can we pick one or the other. I didn't mean to start a dialogue schism.


Thanks for the primer , but the stuff I'm looking for is how the block learn cell is determined and how to modify
the afr target of the block learn. In other words, what is the mathematical algorithm the pcm is using to combine
input from the TPS, MAP, O2 sensor and VSS.

Further, most of the GM boxes max the BL at 105 on the leaning out side. It is possible to change the code so that
BL can have a greater range of fuel trim but more commonly a tuner will change the actual AFR that 128 in the BL
points towards. In other words, the BL at 128 is a state of stochiometry for the fuel and air (14.7:1). It is possible,
for instance, to generate a lean cruise state which changes the afr value at 128 when the block cell is in a low load
value, like 7. This is much like when the block cell reaches 15 and PE mode is enabled and the calculation of pw is
pointed towards attaining the values in the wot table.

Re: the bpw, Pablo, what box are you running. The table may be using different units. My bpw is indicated in usec
and my setting for std op temps (68-80*C) is around 10usec for startup. Could the 135 value possibly be 13.5usec?
Its not clear to me how my 16197427 box uses the bpw. I have the bpw at startup table as well as a table of
choke values that subtract from the stoich value, but it is not clear how the bpw is incorporated in the pw
calculation. I think this would be a mechanism to allow manipulation of the block learn target afr. Does your box
have an injector constant? That could take a similar role as your global? bpw value (135) that you mention.