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Thread: Calculated AirFlow

  1. #1
    Fuel Injected! brian617's Avatar
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    Calculated AirFlow

    Is it possible to get "Calculated AirFlow" into the data stream to data log with a 7427 PCM? Not concerned with it being actual, rather to see what the PCM is seeing.
    89 K1500 Scottsdale 5.7L 5spd 3:42

    Build specs: 97 4 bolt main block 350ci, Eagle rotating assembly with flat tops and 4 valve reliefs, Dart 165cc/67cc Iron Eagle heads, Manely SS valves and springs 110lbs seat @1.7, GM Ram Jet cam 196/206 @.50 .431/.451, stock intake and throttle body, heads and intake gasket matched, Delco EP377 fuel pump @ 22 psi, 427 PCM.

  2. #2
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    with a 7427 being a P6, yes. I'm not that familiar with that code, but if you have an idea of what RAM location it is stored at, you can swap a byte(or two) out of the normal datastream and replace it with the airflow value.
    1995 Chevrolet Monte Carlo LS 3100 + 4T60E


  3. #3
    Fuel Injected! brian617's Avatar
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    That went way over my head lol. What, where and how am I looking for the RAM location?
    89 K1500 Scottsdale 5.7L 5spd 3:42

    Build specs: 97 4 bolt main block 350ci, Eagle rotating assembly with flat tops and 4 valve reliefs, Dart 165cc/67cc Iron Eagle heads, Manely SS valves and springs 110lbs seat @1.7, GM Ram Jet cam 196/206 @.50 .431/.451, stock intake and throttle body, heads and intake gasket matched, Delco EP377 fuel pump @ 22 psi, 427 PCM.

  4. #4
    Fuel Injected! sturgillbd's Avatar
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    From the $0D disassembly the Airflow in gms/sec is at ram location L0255.
    If you are using $0E, it is at L0231. You can replace the prom ID in the datastream with this ram location and it will show the calculated airflow in the via the prom ID.
    See this thread for instructions: http://www.gearhead-efi.com/Fuel-Inj...the-DataStream
    Hope this helps,
    Brian

  5. #5
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    if you have a reasonably commented disassembly, you'll probably find it somewhere in the main RAM area(0000-001FF).

    EDIT: ^ that works.
    1995 Chevrolet Monte Carlo LS 3100 + 4T60E


  6. #6
    Fuel Injected! brian617's Avatar
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    So, change the prom ID in the XDF from 0x4000 to 0x0231? Then relabel "Prom ID" in the ADX to "Calculated AirFlow"?
    89 K1500 Scottsdale 5.7L 5spd 3:42

    Build specs: 97 4 bolt main block 350ci, Eagle rotating assembly with flat tops and 4 valve reliefs, Dart 165cc/67cc Iron Eagle heads, Manely SS valves and springs 110lbs seat @1.7, GM Ram Jet cam 196/206 @.50 .431/.451, stock intake and throttle body, heads and intake gasket matched, Delco EP377 fuel pump @ 22 psi, 427 PCM.

  7. #7
    Fuel Injected! sturgillbd's Avatar
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    In your bin which I assume you are using $0E, there is a section where the datastream for mode 1 is set up. Prom ID is two bytes. Change the address $4000 to 00 in your bin. Change $527F to 02 and $5280 to 31 in the bin. The Prom ID in the datastream should then show the calculated airflow in HEX . Do this on a copy of your bin just in case I misread the hack.
    Here are the addresses from the $0E dis-assembly (hack or hac).
    Code:
    ;--------------------------------------------- 
            ; DEVICE CODE $F4, 8192 RECEIVE MSG 
            ; MODE 1, SUB MODE 1,  ENGINE DIAGNOSTICS 
            ; TYPE $0E 
            ;--------------------------------------------- 
    L5274   FDB $0000   ; NEXT MESAGE ENTRY ADDRESS 
                        ; 
    L5276   FDB $F4     ; MESSAGE ID 
    L5277   FDB $80     ; USE ROM BUFFER 
    L5278   FDB 64      ; NUMBER OF OUTPUT DATA BYTES 
                        ; 
    L5279   FDB $036C   ; ADDRESS OF OUTPUT MSG BUFFER 
    L527B   FDB $036C   ; ADDRESS OF INPUT MSG BUFFER 
                        ; 
                        ;--------------------------------- 
    L527D   FDB $4000   ; 1, EPROM ID WORD MSB 
    L527F   FDB $4001   ; 2, EPROM ID WORD LSB 
                        ;---------------------------------
    The disassembly for $0E is in the $0E thread for the 6395 pcm
    Hope this helps
    Brian

  8. #8
    Fuel Injected! brian617's Avatar
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    Sorry so stupid, this stuff hurts my brain. In the BJDR $0E Hack I see this,

    At L4000 I have 7415

    At L527D I have $4000

    Dont see L5280?
    89 K1500 Scottsdale 5.7L 5spd 3:42

    Build specs: 97 4 bolt main block 350ci, Eagle rotating assembly with flat tops and 4 valve reliefs, Dart 165cc/67cc Iron Eagle heads, Manely SS valves and springs 110lbs seat @1.7, GM Ram Jet cam 196/206 @.50 .431/.451, stock intake and throttle body, heads and intake gasket matched, Delco EP377 fuel pump @ 22 psi, 427 PCM.

  9. #9
    Fuel Injected! sturgillbd's Avatar
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    Look in the bin you are using. There may be a few address differences between BCC codes. I used the last hack in the zip file (BJKZ_HAC.src) Basically the datastream code in the bin reads the values at address $4000 and $4001 to display the Prom ID. You change the code to display the value at 0x0231 which is the ram location for the calculated airflow. Post your bin and what the original BCC was. I will take a look at it later this eve.

    Brian

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