I found this table in my '8063s calibration.

And of coarse code that multiplies the WOT AFR times those correction factors and divides by 128. Why did they put this in? What would it do for the car? Maybe to help lean it out under moderate loads? Its not in the later 8746 calibration. All it does for me is make the motor run different at different loads. Like sort of flat in the middle and leaves a trail of black smoke with the pedal to the floor.

 

That is strange. Can't really see a need for that table. 128's across the board look good.

RBob.

 

Jsut got back from a quick spin with only 128s and its much more uniform. Wonder why they put it in? Maybe to give an extra measure of control over the AFRs in PE?

 

I don't know how to read code very good. But it looks like the "line" for wot a/f correctons. Ya know, if the blms are leaner than 128 then ecm adds fuel? Maybe that table is the amount of correcton based on tps??

 

just for yucks, heres what the code looks like

LDX #$D38B ;Corr. factor vs %TPS table
LDAA L0043 ;%TPS
;
;-Scale %TPS for lookup
;
LDAB #$00A0 ;160
MUL ;(%TPS x 160)/256
ADCA #$0000 ;round if needed
LDAB #$0060 ;96
JSR LFB77 ;2D lookup with SBA
PSHA ;corr. factor ----> stack
;
;Look up PE AFR
;
LDX #$D386 ;PE AFR vs RPMs
BSR LDAC4 ;Lookup subroutine using scaled rpms
;
;-Do %TPS corr. to PE AFR
;
PULA ;get %TPS corr. factor off the stack
MUL ;%TPS corr. factor x PE AFR
ASLD ;x2
BCC LDAF1 ;BRa if no overflow
;
LDAA #$00FF ;Clr overflow
;
LDAF1 TAB ;(TPS corr. factor x PE AFR)/128 ----> B

Ive been fighting this for awhile. I always got fluctuating 02s with varying throttle load and I could never figure out what it was. Im really glad I came across this because it sort of bugged me to have varying performance.

 

Thats probably something along the lines of what they over at GM intended. To give some correction for changing throttle or something. Who knows...