Adjusting parameters that determine BLM cell - GM ECM

Roger Heflin rah at horizon.hit.net
Sun Jan 31 22:07:48 GMT 1999


My car is quite modified (different cam, higher idle).

I am looking at readjusting the parameters that determine what BLM cell is used where.  I
have determined the code that controls it and understand it.

Right now:

First:
BLM = 0 		RPM 	< 700
BLM = 1		 700 <	RPM 	< 1200
BLM = 2		1200 <  RPM 	< 2000
BLM = 3		2000 <  RPM

Then:
BLM = BLM		$0154	< 0x20
BLM += 4	0x20 <	$0154	< 0x32
BLM += 8	0x32 < 	$0154	< 0x50
BLM += 12	0x50 <  $0154

I don't at this time know what $0154, I am figuring it is map related, and I going to
determine what it is later today.

Have others changed the parameters to move BLM Cells around?

Right now, I have rather bad BLM cell coverage.  With 4 or so hours
of data I dont get into BLM cells 0,1 4,5 8,9 12,13 at all.   Those
cells are the ones indexed by rpm (0-700,700-1200), my idle is raised 
to more like 900 (out of gear), 950 (in gear).

Also right now my BLM are way out of tune (ie BLM values close to the bottom rail (110 or
so average), so everything is going to have to be tuned.
		Any help is appreciated from others with
		knowledge about this subject.
		Roger



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