after datalogging with 6E code AUJN and ARAP it looks like there's an ECM commanded idle adder for the first few secs on warm startup of 200 rpm for AUJN and 150 rpm for ARAP.
does anyone know how to reduce these values ?? i think i found a reference to it in line D3CE on the ARAP hac... but not sure how it's calculated with the value of $56 there

;--------------------------------------------------
; IAC TARGET SPEED vs COOLANT TEMP
;
; TBL = .08 * RPM
;--------------------------------------------------
D3AE: LDAA L005D ; COOLANT
D3B0: LDX #$C52E ; INDEX IAC TARGET SPEED TABLE
D3B3: JSR LF3FF ; 2d Lk Up, (No Offset)

D3B6: LDX #$C526 ; INDEX IAC Tables & Params


D3B9: BCLR L00F9,#$20

D3BC: LDAB L00F9
D3BE: BPL LD3C2

;
; ADD IN AN OFFSETS
;
D3C0: ADDA 5,X ; 5 STP'S ADDED FOR COLD ENGINE

D3C2: LD3C2 LDAB L00F8
D3C4: BMI LD3C8
; .... else
D3C6: ADDA 7,X ; 0 RPM/12.5, IAC TARGET OFF SET ADDER
D3C8: LD3C8 LDAB L003B
D3CA: ANDB #$20
D3CC: BEQ LD3D0 ; .... else
D3CE: ADDA $56,X 150 RPM/12.5, ADD RPM OFFSET IF HOT
; SPARK RTD ACTIVE
D3D0: LD3D0 ADDA L01B4
D3D3: LDAB L0036
D3D5: BITB #$20
D3D7: BEQ LD3DB
; ....else
D3D9: LDAA #$50
D3DB: LD3DB STAA L0108

 

ok, it's been awhile since i've done assembly language but as i understand on line d3ce the command is ADDA $56,X
which i'm guessing takes the value at address $56 and adds it to X. sound right??
so where do i find address $56... is that on the chip or somewhere else like the memcal??

 

The value $56 is added to what is in the X register. That result then points to an address. With X being loaded with $C526, the end address being: $C57C

That is in the PROM, which is offset by the ECM to $C000. Subtracting out the offset the BIN/PROM address is $57C

RBob.

 

thanks! that's exactly what i needed... i missed it earlier when i went over the addresses section in the hac.