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Thread: Surging problems footbraking and light/no throttle cruise/coast

  1. #1
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    Surging problems footbraking and light/no throttle cruise/coast

    Most obvious is idling fine, just crack throttle and car goes into heavy surge. Tried making timing in the 1200-1800 rpm area all the same, and that help the size of the wave, but still surges

    Attached log file if you check the comments section I labled some of the surging instances with an S. I think the last one the timing was a dead steady 31 degees and pedal input staying steady but still surges (not nearly as pronounced but obviously the spark ramping up was a contributor to the swing size, but not the cause

    footbrakesurge log is an earlier one before I messed with the timing

    Base running airflow I had put a good bit in but too much and then timing is working to
    Attached Files Attached Files
    Factory Stock 97 SS M6 13.51 @ 104.3 mph
    Stock Longblock LS1 w/ 233/238 P.S.I. Cam
    10.81 @ 126.9 Full interior, six speed on 275 radials, a decade ago

    '99 TA trunk mounted 76mm 6 Liter
    9.0s in '09 @ 153 MPH

    Turbo 5.3 Volvo 740 Wagon
    32psi and still winding out 5th on the highway somewhere

  2. #2
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    Your O2 problem once fixed will help this a whole lot if not fix it all together. After that I highly recommend lowering your min airflow, especially if your running SD only. Haven't checked the tune to see if you are or not, but if your are your min air table needs to be very low - Too high and the engine will add fuel, then pull fuel to try and hit the airflow numbers resulting in a cruise surge especially with light throttle inputs.

    To address timing, pull around 10 degrees out of your whole idle advance table, then turn around and add back around 4 to 6 degrees in your idle areas in the main timing table.

    Wondering if your injector data is correct? What's air fuel doing while the surging is taking place? Is the surging still following your O2's? Just sounding like fueling is really unstable....
    2010 Vette Stock Bottom LS3 - LS2 APS Twin Turbo Kit, Trick Flow Heads and Custom Cam - 12psi - 714rwhp and 820rwtq / 100hp Nitrous Shot starting at 3000 rpms - 948rwhp and 1044rwtq still on 93
    2011 Vette Cam Only Internal Mod in stock LS3 -- YSI @ 18psi - 811rwhp on 93 / 926rwhp on E60 & 1008rwhp with a 50 shot of nitrous all through a 6L80

    ~Greg Huggins~
    Remote Tuning Available at gh[email protected]
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  3. #3
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    stock inj and data far as I know, I inherited this problem.

    I have 13 deg in idle timing table, and @30 and up in that are in main table. 13 is usually low enough to allow it to feed plenty of timing into it (some people put alot into it and it doesnt have any head room to add and "catch" the idle) What are you aiming for there?
    Last edited by GrannySShifting; 06-05-2015 at 09:34 AM.
    Factory Stock 97 SS M6 13.51 @ 104.3 mph
    Stock Longblock LS1 w/ 233/238 P.S.I. Cam
    10.81 @ 126.9 Full interior, six speed on 275 radials, a decade ago

    '99 TA trunk mounted 76mm 6 Liter
    9.0s in '09 @ 153 MPH

    Turbo 5.3 Volvo 740 Wagon
    32psi and still winding out 5th on the highway somewhere

  4. #4
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    Location
    Raleigh, NC
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    6,347
    What computer is in that thing? The logging rate is ridiculous compared to what I get. You got more data in 6 minutes than I get in 30, lol.
    Post a log and tune if you want help

    VCM Suite V3+ GETTING STARTED THREADS / HOW TO's

    Tuner by night
    CPX Tuning
    2005 Corvette, M6
    ECS 1500 Supercharger
    AlkyControl Meth, Monster LT1-S Twin, NT05R's
    ID1000's, 220/240, .598/.598, 118 from Cam Motion

    2007 Escalade, A6
    Stock

  5. #5
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    Shooting for around 6 to 7 degrees max timing in idle areas of your idle advance table then around 4 to 6 more degrees timing or at least almost identical timing to your 1200 and up areas in your main timing table. After that we can adjust your idle airflow tables to stabilize it if the o2's and timing don't fix it.

  6. #6
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    Quote Originally Posted by schpenxel View Post
    What computer is in that thing? The logging rate is ridiculous compared to what I get. You got more data in 6 minutes than I get in 30, lol.
    The newer stufff is like that, this is 07 Silverado ECU
    Factory Stock 97 SS M6 13.51 @ 104.3 mph
    Stock Longblock LS1 w/ 233/238 P.S.I. Cam
    10.81 @ 126.9 Full interior, six speed on 275 radials, a decade ago

    '99 TA trunk mounted 76mm 6 Liter
    9.0s in '09 @ 153 MPH

    Turbo 5.3 Volvo 740 Wagon
    32psi and still winding out 5th on the highway somewhere

  7. #7
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    Mar 2014
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    Raleigh, NC
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    Quote Originally Posted by GrannySShifting View Post
    The newer stufff is like that, this is 07 Silverado ECU
    Yeah I've got an '07 Escalade so probably same or similar computer. The logging rate is quite awesome. Wish my Corvette had something newer.. ah well.
    Post a log and tune if you want help

    VCM Suite V3+ GETTING STARTED THREADS / HOW TO's

    Tuner by night
    CPX Tuning
    2005 Corvette, M6
    ECS 1500 Supercharger
    AlkyControl Meth, Monster LT1-S Twin, NT05R's
    ID1000's, 220/240, .598/.598, 118 from Cam Motion

    2007 Escalade, A6
    Stock

  8. #8
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    Quote Originally Posted by GHuggins View Post
    Shooting for around 6 to 7 degrees max timing in idle areas of your idle advance table then around 4 to 6 more degrees timing or at least almost identical timing to your 1200 and up areas in your main timing table. After that we can adjust your idle airflow tables to stabilize it if the o2's and timing don't fix it.
    Tried that. Absolutely horrendous surging even sitting still in park with that
    Attached Files Attached Files
    Factory Stock 97 SS M6 13.51 @ 104.3 mph
    Stock Longblock LS1 w/ 233/238 P.S.I. Cam
    10.81 @ 126.9 Full interior, six speed on 275 radials, a decade ago

    '99 TA trunk mounted 76mm 6 Liter
    9.0s in '09 @ 153 MPH

    Turbo 5.3 Volvo 740 Wagon
    32psi and still winding out 5th on the highway somewhere