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Thread: lt1 ee Injector tables

  1. #1
    Fuel Injected!
    Join Date
    Mar 2013

    lt1 ee Injector tables

    One of my injector goes wide open and I decided to put stock ls1 since I have a set.
    While I was trying to figure voltage offsets and other stuff I found that lt1 pcm misses some important parameters.
    So I am going to add some new tables used in a ls1 calibration.

    table1 map vs voltage 3d table for voltage offset calibration.
    table2 map vs injector flow
    extending the low pulse offset adder table to 4ms, stock is around 2 ms.
    Goal is to reach super precision and accurate fueling in all fueling modes with rapid intake manifold pressure changes.
    The way I see it, PCM cant compensate enough for cammed cars due to different loads vs manifold pressure and stock pressure regulator not pulling enough.

    From the table below the injector flow change from 28 to 31 pounds by lowering MAP from 100 to 20 kp.{at high vacuum the injector flow more}

    Any thought and suggestions are welcome.
    When tables are ready the fuel pressure should be constant and the vacuum reference will be deleted.
    At later stage I willl try to increase the fuel pressure to stock ls1 to get a better spray pattern.

    First the new 3d table will be really huge 17x28.
    Is there any limits for table size for 68hc11 processor

    I need to convert the flow numbers

    from 58 psi to 43.5 psi

    And interpolate some stuff if I can`t get the voltage in 0.5 increments in the table.
    Last edited by kur4o; 11-10-2017 at 01:22 PM.

  2. #2
    Fuel Injected! spfautsch's Avatar
    Join Date
    Apr 2015
    Are you implying going to a returnless fuel system? Whatever the case, kudos - you're one ambitious hacker.

    I'm not sure I can be of much assistance but I will volunteer to test if I can get most of my winter projects done.
    '95 C4 LT-1 ZF-6, Polo Green
    Comp 467 / XFI 280, UltraProMag RRs, LE1 Heads, Lunati 73925 Springs

    Somebody stole the spark plugs out of my other car, yet it still runs???

  3. #3
    Fuel Injected! vilefly's Avatar
    Join Date
    Sep 2017
    Nice. I have someone with lt-1 big cam problems who might let me test this out.
    All I can offer is the formula this morning, as I am off to work. You may already know it, and there are lots of online calculators.
    Not sure how to calculate voltage offset, though. I am probably stating the obvious.

  4. #4
    Fuel Injected!
    Join Date
    Mar 2013
    Hack was done long time ago but I didn`t have the time to test.
    After I changed oil due to fuel contamination, I managed to idle the car with the patch at 3 bar with the vacuum disconnected. It runned real smooth and the afr was really stable. I put an aeromotive fuel pressure regulator and have plans to bump the pressure to 4 bar if the pump can handle it. It does make some unusual wine when the car is turned off.
    Initial version is only for auto bin. It may need some tweaking. I hope the PCM is fast enough to handle the dynamic fuel flow calculations. Otherwise I will have to move the patch at different locations and test untill sufficient results are obtained.
    I had really hard time interpolating injector data. At least I have the tables done for the ls1 injectors with part number #???#, I will dig it later.

    I did research ls1 fuel system. 97 ls1 corvettes have a fuel pressure regulator on rail at 4 bar, no vacuum applied. Later years they moved it to fuel filter. Ls1 f-bodies have fuel pressure regulator in tank and the return line is close to the tank with a t-union.
    So ls1 is indeed a return system. The return line is not on the rail though.
    It is missing the vacuum reference at the regulator and the PCM calculates the dynamic fuel flow based on manifold vacuum. If you have the correct calibration data it is much more accurate and predictable.

  5. #5
    Fuel Injected!
    Join Date
    Mar 2013
    After initial testing was done, I made a slightly modded version that works with all cars.

    Any input will be appreciated.

    Installation notes.

    Install all patches in the folder. Save bin. Than you can modify the tables if you need to.
    Stock calibration data that is loaded is for stock Gm injectors part number 12554271 at 4 bar with vacuum reference disconnected.
    Values are taken from 98 PCM calibration and interpolated to suit new tables size.

    I hope someone with great excel skills can make a spreadsheet to interpolate data between different formats.
    Manual interpolation is possible but it took me two days to accomplish.
    Attached Images Attached Images
    Attached Files Attached Files

  6. #6
    Fuel Injected!
    Join Date
    Mar 2013
    Does anybody knows el cheapo Factory GM flex fuel sensors or fuel pressure sensors, part numbers, usage, and what signal they produce?


  7. #7
    Fuel Injected! vilefly's Avatar
    Join Date
    Sep 2017
    I have a chart of pressure transducers from various brands that is rather complete, but I have the printout at work. Will have to check back monday, but in the meantime, I have this ebay link that allows you to select various ones with very detailed descriptions on thread, voltage output, and measurement range.

    and they are cheap as you can get.

  8. #8
    Fuel Injected!
    Join Date
    Mar 2013
    Thanks for the link.

    Meanwhile I found some good delco candidates.
    These are used on later model camaro, impala and others. After 2012 MY.

    It has female thread and I need somebody to confirm that the thread is the same as the schrader valve on the lt1 rail.
    If it is the same thread, it will be direct fit and easy hook on some of the free ad channels.

  9. #9
    Fuel Injected!
    Join Date
    Jan 2012
    I've made a little spreadsheet to interpolate between the injector data, it hurts me to read that you had to do it all manually ;)

    Fill the tables with data from LS calbration on LSx Data tab, and the $EE Data tab will update automatically.


    You have to install XonGridd Excel add-on first, for the interpolation functions to work!
    Attached Files Attached Files
    Last edited by dzidaV8; 17 Hours Ago at 05:04 PM.

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