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Thread: Tuning VE open loop - really high values?

  1. #1
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    Tuning VE open loop - really high values?

    Hey all, I've been working on getting my Typhoon LSx swap to idle and had a question. I'm not where I can post a tune yet (don't have my laptop here), but this is a question in general.

    First, my details:

    LQ4 motor, stock internals
    LS6 intake
    60# Siemens injectors
    2 Bar SD converted OS (done as per the instructional video)
    58psi fuel pressure
    No MAF installed, Syclone IAT sensor installed.

    Here is the process I went through to get where I'm at:
    Loaded stock LQ4 tune
    Turned off VATS, EGR, rear O2's
    Failed out the MAF (zero'ed the table, MAF set to 0Hz, high disable to 12800rpm, DTC's set to Mil on First)
    Put in new values for injectors based on the Excel spreadsheet.

    At this point I figured I'd try to get it running. From what I've read, since I don't have a cam, it shouldn't be too much to get it idling. Perhaps the intake swap will throw it off a bit, but I had some interesting results.

    When I started the truck, I had to give it throttle to get it started. If I went below 6% throttle, it died. If I forced closed loop, I could get down to 2%, but any lower, it would die.

    I hooked up the PLX WBO2, and found that in closed loop, I was hitting my targeted afr, but in open loop, I was up around 19

    I double checked my FP when running, it was at 58, no problem. I checked for vacuum leaks, no problem. So I decided to start messing with the VE tables in open loop to see if I could get it to change.

    What I ended up with was drastically higher values in my VE table around idle RPM's/kPa, like nearly double what they were.

    The general question is:

    Should my values change THAT much when I'm only running an intake and injectors? I'm only working on idle at this point.

    Thanks in advance.
    Last edited by PPI Typhoon; 06-19-2011 at 03:32 PM.

  2. #2
    Senior Tuner LSxpwrdZ's Avatar
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    post before and after tune....
    James Short - [email protected]
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  3. #3
    Senior Tuner Ben Charles's Avatar
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    Yea what values are you getting?

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  4. #4
    Advanced Tuner robbyredneck's Avatar
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    should'nt be double. the minute you post both tunes and a scan you will get instant help.
    04 6.0 silvy china turbo
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    03 stroker evo ww
    00 ss camaro

  5. #5
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    Ok I'll post a tune when I have access to the laptop.

    I remember specifically around 1200rpm, 25-30kPa:

    The original value was 55'ish, and I ended up at 90'ish, this was after I did a full 1.5 multiply on the table originally. The stock value was around the 40 in that range.

    I'm just wondering if that much of a change is normal.

    Thanks for the quick replies.

  6. #6
    Senior Tuner Ben Charles's Avatar
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    What mods do you have?

    Email Tunes, [email protected]
    96 TA Blown/Stroked, 4L80E/Fab 9
    15 C7 A8 H/C 2.3 Blower/PI
    14 Gen 5 Viper
    Custom Mid Engine chassis, AKA GalBen C

  7. #7
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    Quote Originally Posted by Ben Charles View Post
    What mods do you have?
    I've listed everything above, but basically it's an LQ4 with an LS6 intake, 60lb injectors. I am running a turbo, but it's not even hooked into the intake yet.

  8. #8
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    Without the tune file or the vehicle in front of us we can only guess ... my guess would be that the data for the injectors (that you put in) are suspect or a vacuum leak.

  9. #9
    Senior Tuner LSxpwrdZ's Avatar
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    Either injector data is wrong or you don't have the maf failed.
    James Short - [email protected]
    Located in Central Kentucky
    ShorTuning
    2020 Camaro 2SS | BTR 230 | GPI CNC Heads | MSD Intake | Rotofab | 2" LT's | Flex Fuel | 638rwhp / 540rwtq
    2002 Camaro | LSX 427 | CID LS7's | Twin GT5088's | Haltech Nexus R5 | RPM TH400

  10. #10
    Tuner in Training
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    Thanks for the help everyone. I realized that I had loaded an old tune, that had bad injector data in it. Now it's idling, minor changes to the VE table, and it even idles great in closed loop.

    Thanks everyone for the tips.