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Thread: How do I add fuel?

  1. #1
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    Default How do I add fuel?

    My ltft's are adding 5-7% fuel in part throttle operation. I know I need to get these 0 or slightly negative to get the ltft's 0 at WOT. Where can I go to add the fuel? I was looking to add it to the main ve table, but after doing some reading on ls1tuning.com and ls1tech.com it seems like that might not work out too well. Please help this tuning newbie.

    ps: Flashscan rocks! I cant get over how awesome it is.

  2. #2
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    Well, there are several ways and places to work out the LTFTs. I'm a begineer like you, so please keep that in mind...

    My 2002 F-body was running too lean. The LTFTs were running in the +5 to +6 ranges, pretty much across the whole range. Here are the three things I know you can change to get them down to toward zero, or slightly negative:

    VE table
    IFR table
    MAF table

    I've been reading and experimenting with all three. The best way I have found to get results across the board is with the MAF table. I managed to get everything above 10inHG-MAP to be in the -1 to -2 ranges with the MAF table. Unfortunately, everything below 10inHG-MAP is now running in the -6 to -8 ranges... I'm now trying to use the VE table to bring down those areas. I'm really not sure if this is the correct approach, but it seems to be working. Maybe someone else (who knows what they are doing) can chime in.

  3. #3
    Lifetime Member jfpilla's Avatar
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    Those are the main tables that are used to set trims. You will notice that almost anything you change in any airflow, fuel and even timing table will affect trims.
    Suggest you list your mods so that suggestions can be better targeted. ex.If you changed your air intake you might go to the MAF. Change injectors and go to IFR. Change everthing and the fun begins.
    You should use MAP kPa. Most tables use it and is the standard for understanding each other.
    2003 red vert
    Mods:
    LS7 crate engine, wet sump, 24xx reluctor
    LPE 100mm MAF
    Vararam, cold air intake and bridge
    RPM Level 6/4L60e trans
    3.42 gears
    Yank SS3600
    1-7/8" AR headers
    Z06 exhaust
    470rwhp 437rwtq
    1/8th mi-1.526-60'-6.862-1/8th-@100.74mph

  4. #4
    Lifetime Member 87gmc's Avatar
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    Same problem here what should I do?

    99 GMC 5.3L All stock except for k&N filter. Where do I start to get them down to 0%

    Gotta love the way efilive exports it into excel :-)


    Cell# MAP/RPM boundaries Bank-1 Bank-2
    0 MAP 0.00..33.0 kPa/RPM 0..900 0.00% 1.56%
    1 MAP 0.00..33.0 kPa/RPM 900..1400 0.00% 1.56%
    2 MAP 0.00..33.0 kPa/RPM 1400..2200 11.72% 12.30%
    3 MAP 0.00..33.0 kPa/RPM 2200+ 11.72% 12.30%
    4 MAP 33.0..55.0 kPa/RPM 0..900 1.95% 4.49%
    5 MAP 33.0..55.0 kPa/RPM 900..1400 4.88% 6.45%
    6 MAP 33.0..55.0 kPa/RPM 1400..2200 9.77% 9.37%
    7 MAP 33.0..55.0 kPa/RPM 2200+ 11.72% 12.30%
    8 MAP 55.0..77.0 kPa/RPM 0..900 11.72% 12.30%
    9 MAP 55.0..77.0 kPa/RPM 900..1400 7.81% 8.40%
    10 MAP 55.0..77.0 kPa/RPM 1400..2200 8.79% 9.37%
    11 MAP 55.0..77.0 kPa/RPM 2200+ 11.72% 12.30%
    12 MAP 77.0+ kPa/RPM 0..900 11.72% 12.30%
    13 MAP 77.0+ kPa/RPM 900..1400 11.72% 12.30%
    14 MAP 77.0+ kPa/RPM 1400..2200 11.72% 12.30%
    15 MAP 77.0+ kPa/RPM 2200+ 11.72% 12.30%
    16 P/N: A/C On 11.72% 12.30%
    17 P/N: A/C Off 11.72% 12.30%
    18 In gear: A/C On 11.72% 12.30%
    19 In gear: A/C Off 4.88% 5.47%
    20 Cold idle 5.86% 6.45%
    21 Deceleration 10.74% 11.72%
    22 WOT 10.74% 14.65%

  5. #5
    Lifetime Member jfpilla's Avatar
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    Quote Originally Posted by 87gmc
    Same problem here what should I do?

    99 GMC 5.3L All stock except for k&N filter. Where do I start to get them down to 0%

    Gotta love the way efilive exports it into excel :-)


    Cell# MAP/RPM boundaries Bank-1 Bank-2
    0 MAP 0.00..33.0 kPa/RPM 0..900 0.00% 1.56%
    1 MAP 0.00..33.0 kPa/RPM 900..1400 0.00% 1.56%
    2 MAP 0.00..33.0 kPa/RPM 1400..2200 11.72% 12.30%
    3 MAP 0.00..33.0 kPa/RPM 2200+ 11.72% 12.30%
    4 MAP 33.0..55.0 kPa/RPM 0..900 1.95% 4.49%
    5 MAP 33.0..55.0 kPa/RPM 900..1400 4.88% 6.45%
    6 MAP 33.0..55.0 kPa/RPM 1400..2200 9.77% 9.37%
    7 MAP 33.0..55.0 kPa/RPM 2200+ 11.72% 12.30%
    8 MAP 55.0..77.0 kPa/RPM 0..900 11.72% 12.30%
    9 MAP 55.0..77.0 kPa/RPM 900..1400 7.81% 8.40%
    10 MAP 55.0..77.0 kPa/RPM 1400..2200 8.79% 9.37%
    11 MAP 55.0..77.0 kPa/RPM 2200+ 11.72% 12.30%
    12 MAP 77.0+ kPa/RPM 0..900 11.72% 12.30%
    13 MAP 77.0+ kPa/RPM 900..1400 11.72% 12.30%
    14 MAP 77.0+ kPa/RPM 1400..2200 11.72% 12.30%
    15 MAP 77.0+ kPa/RPM 2200+ 11.72% 12.30%
    16 P/N: A/C On 11.72% 12.30%
    17 P/N: A/C Off 11.72% 12.30%
    18 In gear: A/C On 11.72% 12.30%
    19 In gear: A/C Off 4.88% 5.47%
    20 Cold idle 5.86% 6.45%
    21 Deceleration 10.74% 11.72%
    22 WOT 10.74% 14.65%
    I think the 99' MAF has an impact on the 4l60. If so, reduce the Injector Flow Rate by 10% and see the result.
    2003 red vert
    Mods:
    LS7 crate engine, wet sump, 24xx reluctor
    LPE 100mm MAF
    Vararam, cold air intake and bridge
    RPM Level 6/4L60e trans
    3.42 gears
    Yank SS3600
    1-7/8" AR headers
    Z06 exhaust
    470rwhp 437rwtq
    1/8th mi-1.526-60'-6.862-1/8th-@100.74mph

  6. #6
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    hmmm, so if I reduce my injector flow rate based on map then that will make the ltft's go negative? Interesting... Now if a 2002 ls1 has 28.6 # injectors then why are mine flowing from 28.7 to 31.4, as map pressure increases?

    As for mods, lid, headers, cats, catback, S2, SLP rocker arms.

    So I would want to reduce my IFR by 7% across the board, so multiply the whole thing by -7% ?

  7. #7
    Lifetime Member 87gmc's Avatar
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    Quote Originally Posted by jfpilla
    Quote Originally Posted by 87gmc
    Same problem here what should I do?

    99 GMC 5.3L All stock except for k&N filter. Where do I start to get them down to 0%

    Gotta love the way efilive exports it into excel :-)


    Cell# MAP/RPM boundaries Bank-1 Bank-2
    0 MAP 0.00..33.0 kPa/RPM 0..900 0.00% 1.56%
    1 MAP 0.00..33.0 kPa/RPM 900..1400 0.00% 1.56%
    2 MAP 0.00..33.0 kPa/RPM 1400..2200 11.72% 12.30%
    3 MAP 0.00..33.0 kPa/RPM 2200+ 11.72% 12.30%
    4 MAP 33.0..55.0 kPa/RPM 0..900 1.95% 4.49%
    5 MAP 33.0..55.0 kPa/RPM 900..1400 4.88% 6.45%
    6 MAP 33.0..55.0 kPa/RPM 1400..2200 9.77% 9.37%
    7 MAP 33.0..55.0 kPa/RPM 2200+ 11.72% 12.30%
    8 MAP 55.0..77.0 kPa/RPM 0..900 11.72% 12.30%
    9 MAP 55.0..77.0 kPa/RPM 900..1400 7.81% 8.40%
    10 MAP 55.0..77.0 kPa/RPM 1400..2200 8.79% 9.37%
    11 MAP 55.0..77.0 kPa/RPM 2200+ 11.72% 12.30%
    12 MAP 77.0+ kPa/RPM 0..900 11.72% 12.30%
    13 MAP 77.0+ kPa/RPM 900..1400 11.72% 12.30%
    14 MAP 77.0+ kPa/RPM 1400..2200 11.72% 12.30%
    15 MAP 77.0+ kPa/RPM 2200+ 11.72% 12.30%
    16 P/N: A/C On 11.72% 12.30%
    17 P/N: A/C Off 11.72% 12.30%
    18 In gear: A/C On 11.72% 12.30%
    19 In gear: A/C Off 4.88% 5.47%
    20 Cold idle 5.86% 6.45%
    21 Deceleration 10.74% 11.72%
    22 WOT 10.74% 14.65%
    I think the 99' MAF has an impact on the 4l60. If so, reduce the Injector Flow Rate by 10% and see the result.
    Can you explain how the maf impacts the trans. What does it effect or...........

  8. #8
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    the Maf is used to calculate the ammount of air entering the engine.
    The ammount of air that enters the engine is used to calculate the engine's torque output.
    Shift speed, line pressure, and torque reduction are all adjusted based on the engine's calculated torque output.

  9. #9
    Lifetime Member jfpilla's Avatar
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    Quote Originally Posted by Blk02Ls1A4
    hmmm, so if I reduce my injector flow rate based on map then that will make the ltft's go negative?

    >>>Yes, your telling the PCM that you have smaller injectors than what you have. The PW is increased to add fuel and the adjustment to add air causes less Pos. trims.

    Interesting... Now if a 2002 ls1 has 28.6 # injectors then why are mine flowing from 28.7 to 31.4, as map pressure increases?

    >>> Don't know. Why do you ask?

    As for mods, lid, headers, cats, catback, S2, SLP rocker arms.

    So I would want to reduce my IFR by 7% across the board, so multiply the whole thing by -7%

    >>> -7% or any # to determine what changes result in what levels for your car.
    2003 red vert
    Mods:
    LS7 crate engine, wet sump, 24xx reluctor
    LPE 100mm MAF
    Vararam, cold air intake and bridge
    RPM Level 6/4L60e trans
    3.42 gears
    Yank SS3600
    1-7/8" AR headers
    Z06 exhaust
    470rwhp 437rwtq
    1/8th mi-1.526-60'-6.862-1/8th-@100.74mph

  10. #10
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    Quote Originally Posted by Blk02Ls1A4
    hmmm, so if I reduce my injector flow rate based on map then that will make the ltft's go negative? Interesting... Now if a 2002 ls1 has 28.6 # injectors then why are mine flowing from 28.7 to 31.4, as map pressure increases?

    As for mods, lid, headers, cats, catback, S2, SLP rocker arms.

    So I would want to reduce my IFR by 7% across the board, so multiply the whole thing by -7% ?
    The pressure is increasing in the intake manifold but, the fuel pressure is not manifold referenced so the flow of the injector has to be increased to "fight" the extra pressure in the manifold as the MAP rises.

    On '99-'03 GM trucks the fuel pressure is manifold referenced meaning it rises as the MAP rises. The values for IFR vs. MAP are constant in a system like this.

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