165 to late MAF

[Thomas Matthews]

Ah-hah!
Now it's all clear as mud...
So, what do you think would happen if the flag at b2 were set off, to
indicate FM MAF?
Could you build in the frequency to GPS code from another app, and through
some testing come up with a freq map that would allow the use of a new MAF?
I've never seen commented code from a FM MAF application.
Wish I knew how to program- this stuff is facinating!
Tom
----- Original Message -----
From: Peter Gargano <peter at ntserver.techedge.com.au>
To: <gmecm at efi332.eng.ohio-state.edu>
Sent: Sunday, November 28, 1999 12:45 AM
Subject: Re: 165 to late MAF


> Not wishing to labour the point (Craig said it all), and as I have all the
> code right here, right now...
>
> Thomas Matthews wrote:
> >
> > Then either the hack is wrong, or it is a unused part of code, or the
ECM
> > has its own Voltage to frequency converter.
>
> Well you're sort of right - but The Hac IS CORRECT, and the ECM has a
converter,
> but it's all in software - no F->V hardware, just a read of the A/D
converter.
>
> Check the SOURCE!... (ECMguy's HAC)
>
> 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
>                         ;
>
> ==== and
>
> ;   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    #$04            ; b2, ANALOG MAF
>         BNE     LF7AC           ; BR IF b2, (ANALOG MAF )
>                                 ; ... else
>         ;
>         ; DIGITAL (FM) MAF
>         ; (OLD BOSCH TYPE)
>         ;
>         LDD     L00ED           ; 8 cntr Lps MAS
>
>
> ==== and
>
> ;**************************************************
> ; ANALOG MAF
> ;
> ; MULT ANALOG VAL x 7 TO LOOK
> ; LIKE FM MAF AND USE FM TABLES
> ;**************************************************
> LF7AC:  LDAA    #$A0            ; A/D Ch A, Mass Air Sensor
>         JSR     LF1BE           ; To A/D subroutine
>
> etc..
>
> Sorry to those who find code a bit of a bore.
> --
> Peter Gargano