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Thread: Error in my tune-$100 to find it for someone

  1. #1
    Lifetime Member 67SS509's Avatar
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    Default Error in my tune-$100 to find it for someone

    Guess I have reached the point I am desperate enough to give someone $100 to show me whats wrong. I'm 99.9% sure it's in the software, probably with the injector tuning. Gets worse with increasing ECT temps. Breaks up and backfires under load when you try to go WOT in the 4000-6000 rpm range. AFR spikes up when it does but injector duty cycle stays up. Runs good around 125 degrees but goes to crap by 150 degrees ECT. Motor ran great in my truck but will not in the Camaro.

    Some specs:
    98 Camaro
    LS7 427-large cam-ETP heads-GMMP carb style intake-90mm TB
    Powerglide trans with 5600 stall
    99-04 style computer and new stand alone harness
    48lb Racetronic injectors
    Aeromotive 1000 pump and system (fuel starvation is not the problem)
    Truck coils
    Base tune is from 2001 Camaro
    Crank sensor and cam sensor have been checked and replaced and checked
    No VSS
    All grounds and + cables have been ohmned

    Will PayPal $100 to whoever pinpoints the problem.

    On the log start at frame 465 for the good WOT and frame 3142 for the one breaking up.
    Attached Files Attached Files
    2002 Chevy truck, SCSB 2WD, Stroked LS3 w/Big Mutha Thumper cam
    2002SS Camaro LS7/427 with stock suspension setup
    2012 Chevy truck, SCSB 2WD, Magnaflow exhaust + K&N

  2. #2
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    Looks like a rev limiter to me! This looks like the dragster on the 2-step. You dont have an aftermarket ignition box or 2-step do you? Most likely not because of the temp but you never know.

    There are just 2 things, 1) Fuel and 2) Ignition

    You should include the injector pulse widths too

    Are you positive the Fuel Pressure is stable at those trouble areas?

    Lee
    Last edited by LS1_Dragster; August 26th, 2009 at 02:17 PM.

    230" Dragster - 2000 LS1, 02020003 Speed Density, PRC 2.5 Heads,
    MS3 Cam 237/242 .603/.609, Vic Jr. intake, Holley 1000CFM TB,
    PowerGlide, 5000 stall converter. 8.70@154 MPH

    My Projects Homepage: http://www.horsepowerracing.com

  3. #3
    Lifetime Member SSpdDmon's Avatar
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    Why is B4004 zero'd out above 3600rpm?
    Why does your desired airflow table have zeros in it?
    Why did you adjust spark dwell times?
    Why is your idle overspeed spark correction adding timing?
    Why are the MAF DTC Processing Enablers disabled? -- this might be the key here. If the MAF tests aren't running, the MAF might not be failing...



    I can't open your log without v7.5. But, what does your WB say is happening when it cuts out?
    Last edited by SSpdDmon; August 26th, 2009 at 02:18 PM.

  4. #4
    Lifetime Member 5.7ute's Avatar
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    Quote Originally Posted by SSpdDmon View Post
    Why is B4004 zero'd out above 3600rpm?
    Why does your desired airflow table have zeros in it?
    Why did you adjust spark dwell times?
    Why is your idle overspeed spark correction adding timing?
    Why are the MAF DTC Processing Enablers disabled? -- this might be the key here. If the MAF tests aren't running, the MAF might not be failing...



    I can't open your log without v7.5. But, what does your WB say is happening when it cuts out?
    The log is showing a p0102 code so the maf is failing.
    I havent done anything with the LS7 but wouldnt 24deg adv be on the high side for this combo. Is there any chance you are getting detonation? This can cause the lean readings you are seeing & will become more prevelant as engine temps rise.
    The Tremor at AIR

  5. #5
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    No,

    Can you please log Maf Hz. Looks like the MAF is failing. If you see the first WOT run it appears to be ok... but you do not rev past 6krpm.
    "All that is needed for the triumph of evil is that good men do nothing..."

  6. #6
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    You are running in speed density never mind... Let me look through the tune.
    "All that is needed for the triumph of evil is that good men do nothing..."

  7. #7
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    Well....
    Check to see if you have a bad coil.

    Those lean spikes are misses.
    "All that is needed for the triumph of evil is that good men do nothing..."

  8. #8
    Lifetime Member 67SS509's Avatar
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    Thanks for the help here guys!
    Attached is a log from today. Injectors are logged on this one.

    To answer some of the questions............

    -It is mafless
    -B4004 table is stock from factory as trucks and f-bodies, Corvettes have this table filled all the way down. Filled my table and is included in the today's log. Didn't help.
    -O's in airflow table...glitches from so many flashes I guess..corrected
    -I have swapped out everypart on the car but the paint
    -The only table with ECT involvement is B3702....Injection Timing...don't know what to try with this one
    -Fuel is MS109 lead free VP Racing...ran 2 years on this with no problems
    -If it was a real misfire from a bad coil or injector it would throw a code
    Attached Files Attached Files
    Last edited by 67SS509; August 27th, 2009 at 06:30 AM.
    2002 Chevy truck, SCSB 2WD, Stroked LS3 w/Big Mutha Thumper cam
    2002SS Camaro LS7/427 with stock suspension setup
    2012 Chevy truck, SCSB 2WD, Magnaflow exhaust + K&N

  9. #9
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    Why not use a tune for a manual trans instead of an auto? This is what I did for the dragster. Maybe there are issues the computer's having without any feedback from the auto trans.

    I would find a tune for a manual and just copy over your fuel and spark tables.

    Lee

    230" Dragster - 2000 LS1, 02020003 Speed Density, PRC 2.5 Heads,
    MS3 Cam 237/242 .603/.609, Vic Jr. intake, Holley 1000CFM TB,
    PowerGlide, 5000 stall converter. 8.70@154 MPH

    My Projects Homepage: http://www.horsepowerracing.com

  10. #10
    Lifetime Member 67SS509's Avatar
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    When I had the 98 PCM in it I did try a 6-speed tune but it did the same thing.
    2002 Chevy truck, SCSB 2WD, Stroked LS3 w/Big Mutha Thumper cam
    2002SS Camaro LS7/427 with stock suspension setup
    2012 Chevy truck, SCSB 2WD, Magnaflow exhaust + K&N

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