lt170chevelle

iTrader: (2)

ok i know about the + or - BLM is what you reference by but how do you adjust them? in my tuner cat i only see two tables and they are rpm and map bounderies!?! what the heck do the bounderies do?how do i adjust for each bank? on my last scan i had one side right at 128 and the other at 127. i just dont see where to adjust these at.

y2khawk

iTrader: (5)

for LT1 BLM, 128 is middle of the road - ie 0% being added/removed.

I believe max + is 160 and min - is 96ish

the boundary tables are just the RPM and MAP thresholds that determine the BLM cell you are in.

What exactly are you trying to adjust? Since your BLM's are pretty close you really don't need to adjust it IMO.

Doc99SS

iTrader: (2)

You dont need to do anything with the boundaries, unless you have a huge cam. Concerning the BLM values (as said above) the perfectly tuned ECM having no fuel adjustments is at 128, thats baseline. If your engine is a MAP system and OBD1, then you have 16 fuel trim cells, 0 thru 15. FTC 0 should be your idle FTC. WOT is FTC 15. The boundaries split up the 16 FTCs into a 4 x 4 grid divided by MAP and RPM. In order to adjust the BLMs, you will have to know the BLM value for some or most of the FTCs. Each FTC has its unique BLM value. You edit the VE values in the VE table, in the appropriate FTC zone. For example, If the BLM happens to be 144, then the computer is adding fuel by % = 144-128 divided by 128, which is 12.5%. If this 144 BLM value is for FTC 10, then you go into the VE table and bump up the VE values by 12.5% for the MAP and RPM cells that comprise FTC 10. There is alot more info about this type of system on www.thirdgen.org, go to the DYI prom section.

Edit: If you have tuned the ECM so that all BLMs are between 122 and 134, you are done with that part of your tuning.