Re: 89 MAF Volt to freq conversion

["Thomas Matthews" <tmatthew@stny.lrun.com>]

Here's what I have from ECM Guy.. with the address of the flag and some
other tidbits.

LC014:  FCB     $B4     ; 1011 0100      Air Fuel Opt Word 1, ($B4)
                        ;
                        ; b7 = Use Filter for Air flow
                        ; b6 = Use TCC for Shft Lamp Cnt'l
                        ; b5 = Req Clsed Lp for Can Purge
                        ; b4 = VATS Enable
                        ;
                        ; b3 =
                        ; b2 = Analog MAF Meter in use (vs FM DIGITAL)
                        ; b1 = Single Fire Mode
                        ; b0 = Manual Xmission
                        ;
;   Calc Air flow Fm MAF Air meter
;
; ESTABLISH 1 of 2 TYPES OF MAF, ANALOG (0 5 VDC)
; OR DIFITAL ) 32 Hz to ___ Hz)
;
;******************************************************

        ;
        ; CK AFR MD WD1 FOR ANALOG MAF
        ;
LF76A:  LDAA    LC014           ; Fuel/Air Mode Wd 1
        BITA    #$04            ; b2, ANALOG MAF
        BNE     LF7AC           ; BR IF b2, (ANALOG MAF )
                                ; ... else
        ;
        ; DIGITAL (FM) MAF
        ; (OLD BOSCH TYPE)
        ;
        LDD     L00ED           ; 8 cntr Lps MAS

;**************************************************
; ANALOG MAF
;
; MULT ANALOG VAL x 7 TO LOOK
; LIKE FM MAF AND USE FM TABLES
;**************************************************
LF7AC:  LDAA    #$A0            ; A/D Ch A, Mass Air Sensor
        JSR     LF1BE           ; To A/D subroutine


----- Original Message -----
From: "Mark Romans" <romans@pacbell.net>
To: <gmecm@efi332.eng.ohio-state.edu>
Sent: Thursday, January 06, 2000 12:03 AM
Subject: Re: 89 MAF Volt to freq conversion


> I have  a copy of the 86 hac, what is the address of the switch?  I will
> look in the 89 code to see if I can find the same thing.  I think the
> problem is that the code will still only read up to 255 grams/sec even if
> the maf would read more.  To convert it to load the whole fuel and spark
> maps would have to be re-calibrated.
> Mark
> -----Original Message-----