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Thread: New car, bad tune

  1. #1
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    New car, bad tune

    Bought a 01 SS with cam, long tubes, 3600 stall, ls3 injectors. Car has a really hard time starting cold. Usually rough idles for a few seconds then dies. Do this several times and it will idle very low and rough. Really can't give any gas or it dies. After it painstakingly reaches 110-120 ECT, it's like something clicks (not physically) and it runs fine. I bought the tuning software wanting to play with it, but I had a professional shop look at it and there was a ton of stuff changed and I just don't know where to start. The shop around here is $150/hr so I figured I would try to get some help here first as to where to start.
    I did a little logging and I will post the tune. I have a wide band coming this week.
    Thank you

    -Mike
    Attached Files Attached Files

  2. #2
    Tuning Addict 5FDP's Avatar
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    For one, the injector data in the tune is not right at all.

    The flow rate is way up around 60lb/hr and LS3 injectors are only around 42lb/hr. So we are going to need to fix that first. I will post the LS1 to LS3 injector data spreadsheet. The spreadsheet is pre-populated with LS3 data and the LS1 style data you can copy over. This spreadsheet also lets you copy/paste in other LS3 type data and work on the older GEN 3 calibrations.

    So copy over the flow rate, min injector pulse, short pulse adder and offset data into your tune to fix one of your biggest issues.

    From here I would honestly go back to much of the stock tune to make your life easy. Because you don't know exactly what was done to the tune and because I can only imagine that so much was done with the wrong injector data, a ton of this tune is going to be way wrong.


    This is a speed density tuned vehicle because the MAF is disable per the tune and the VE table that controls fueling is way out of line right now. I would copy over a stock VE table, stock base running airflow data and start over using a wideband.


    Do those changes and see if the starts better.
    Attached Files Attached Files
    2016 Silverado CCSB 5.3/6L80e, not as slow but still heavy.

    If you don't post your tune and logs when you have questions you aren't helping yourself.

  3. #3
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    Thank you so much for taking the time to look at that and reply pointing me where to start. I will do what you suggested, log and re-post (tomorrow after work!). Thanks again.

    -Mike

  4. #4
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    Hey 5F, I changed according to the table you posted. Car started up first try and idled pretty decent. Thank you for posting that.

  5. #5
    Tuning Addict 5FDP's Avatar
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    Good to hear. Now it's just taking the steps to redo the VE table with a wideband to dial the rest of the fueling in now that the injector data is fixed.

    Don't go around flooring it until you are able to cover that.
    2016 Silverado CCSB 5.3/6L80e, not as slow but still heavy.

    If you don't post your tune and logs when you have questions you aren't helping yourself.

  6. #6
    Potential Tuner Greenesa's Avatar
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    I had the same issue

  7. #7
    Potential Tuner Greenesa's Avatar
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    So the topic is current yet