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Thread: vortec with tbi injection

  1. #1
    Electronic Ignition!
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    vortec with tbi injection

    has anyone re-tuned a vortec engine running tbi with success to run good. my setup is a stock vortec 5.7 i have a open 4 barrel intake with tbi adapter plate, headers y pipe and no cat with a basic aftermarket muffler. what did you do for the spark tables? my ecm is 7427 bnkm code, 5.7-4l80e combo. i have the fuel basically figured out a bit rich right now but i figure the spark tables need adjusted before i go any leaner on the mix. all sensors ect.. are brand new right now with all the tbi free mods and adjustable fpr inline, high flow fuel pump blah blah blah all the regular goodies done. i have a moates apu1 to do tuning ect.

  2. #2
    Super Moderator dave w's Avatar
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    For the timing table I started with a factory 1998 Vortec L31 Timing Table. Other members might share a better timing table?

    To optimize the fuel tables, I used the Wide Band Oxygen Sensor (WBO2) spreadsheet available here:http://www.gearhead-efi.com/Fuel-Inj...g)-Spreadsheet

    Other members might share lower cost / shortcut methods that possibly work well without WBO2 or a factory Vortec Timing table?

    The information / tuning tips I posted above have worked well for me.

    dave w
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  3. #3
    Electronic Ignition!
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    welll i made changes to table and clicked commit changes and it didnt dsave the changes so now what did i do wrong?

  4. #4
    Electronic Ignition!
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    it looks like i cannot insert values greater than what is in the table currently

  5. #5
    Super Moderator dave w's Avatar
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    The spreadsheet is not copy / paste ready. The Vortec Timing Tables and TBI Timing Tables are different sizes. Interpolation is required to configure the Vortec Table into the TBI Table.

    The attached picture shows the Table Sizes, RPM's vs. Kpa's

    dave w
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  6. #6
    Electronic Ignition!
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    i meant if i go into the tbi map lets say that the very first box is 11.1 for value and i put 12 in that box and click commit changes what happens next is the table closes and i open it back up the value is 11.1 again, if i make the value less than 11.1 it closes after commit changes i open it the value stays what it was changed to.

  7. #7
    Super Moderator dave w's Avatar
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    Cell values that have been edited should be red. Before I close a table I've edited, I click save first. Sometimes double clicking the table cell is needed to initiate an edit.

    dave w
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  8. #8
    Carb and Points!
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    "open 4 barrel intake with tbi adapter"

    Morning, I am new to the ecm/pcm/ecu tuning side of the performance world, but a couple of questions.

    First, where does the performance lack that you are trying to tune? Low, mid or high rpm?
    With a open plenum intake you are going to suffer low to mid-range drivability and performance in most cases.
    We found even with carb. streetable engines that dual plane intakes provide much better street manors and performance gains.

    Next, has your intake been tapered where the tbi plate bolts to it? The TBI bore is wider then a standard square bore intake and will have sharp edge for the air/fuel mixture to flow around causing a disruption. My dual plane intake is off the engine now and I am tapering that narrow area and rounding out that flow for lack of a better term before transferring that engine into my '94 Suburban and installing the TBI. Have not had my coffee yet.
    I have found a 1" spacer that takes into account the narrow square bore pattern and puts the taper in the spacer, but it was pricey. Considering I have access to tools to mod the intake, I am going that route.

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