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Thread: LT1 24x guys, what's wrong with this tune? Car starts then dies, VATS is disabled

  1. #1
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    LT1 24x guys, what's wrong with this tune? Car starts then dies, VATS is disabled

    The car will start and then dies almost immediately. I know the car runs because I have another PCM from the previous build with a VE tune that it will at least start and idle (albeit rough) it does run. The computer with the VE tune is locked unfortunately so I cannot read it. The main points of my setup are in my signature. Bosch 80 lb injectors. Thanks in advance.
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    1997 LT1, 24x, D1SC, LE2 heads/intake, 565/579 lift 223/235 @ .050 114 LSA cam

  2. #2
    Tuning Addict 5FDP's Avatar
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    Did the injectors come with data? You can't just plug in 80lb/hr in the injector flow rate and call it good. The injectors need to have all the data and the flow rate needs to be setup for the fuel pressure you are running and the style of fuel system, be it a return/returnless etc.

    Are you running a stock LS1 1 bar map sensor??

    Are you going to run a MAF or is it speed density only??
    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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    Quote Originally Posted by 5FDP View Post
    Did the injectors come with data? You can't just plug in 80lb/hr in the injector flow rate and call it good. The injectors need to have all the data and the flow rate needs to be setup for the fuel pressure you are running and the style of fuel system, be it a return/returnless etc.

    Are you running a stock LS1 1 bar map sensor??

    Are you going to run a MAF or is it speed density only??
    I still have the stock 1 bar LT1 MAP sensor. The tune is for running the MAF. The injectors went on the car a long time ago so any data that came with them is probably long gone.
    1997 LT1, 24x, D1SC, LE2 heads/intake, 565/579 lift 223/235 @ .050 114 LSA cam

  4. #4
    Tuning Addict 5FDP's Avatar
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    Are the linear and offset settings the same for an LT1 sensor and a LS1 sensor??

    You'd need to make sure of that or swap to the LS1 style sensor to always know you have the right data. But if this vehicle is really procharged like your sig says you need a 2 or 3 bar MAP sensor so you can probably log boost and so that you can use the 2 or 3 bar speed density OS upgrade to have boost enrichment and a larger VE table for tuning boost.

    Not having injector data is going to make this very hard to tune.
    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.

  5. #5
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    I lied. It has a 2 bar MAP
    1997 LT1, 24x, D1SC, LE2 heads/intake, 565/579 lift 223/235 @ .050 114 LSA cam

  6. #6
    Tuning Addict 5FDP's Avatar
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    Then that is your first major problem. 1 bar settings with a 2 bar sensor won't want to start.

    The other stuff about the 2 bar OS should still be done.
    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.

  7. #7
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    Quote Originally Posted by 5FDP View Post
    Are the linear and offset settings the same for an LT1 sensor and a LS1 sensor??

    You'd need to make sure of that or swap to the LS1 style sensor to always know you have the right data. But if this vehicle is really procharged like your sig says you need a 2 or 3 bar MAP sensor so you can probably log boost and so that you can use the 2 or 3 bar speed density OS upgrade to have boost enrichment and a larger VE table for tuning boost.

    Not having injector data is going to make this very hard to tune.
    I have located my old invoice for my injectors. I have an email out to the vendor to send me the data for my exact injectors.
    1997 LT1, 24x, D1SC, LE2 heads/intake, 565/579 lift 223/235 @ .050 114 LSA cam

  8. #8
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    I have acquired the injector data
    1997 LT1, 24x, D1SC, LE2 heads/intake, 565/579 lift 223/235 @ .050 114 LSA cam

  9. #9
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    Quote Originally Posted by rockbottom6218 View Post
    I have acquired the injector data
    Once you enter the correct injector data report back and let us know if there is any improvement.

    Did you use a stock harness for the conversion? If so did you swap the injectors and coils wiring to the LS1 firing order? Changing it in the PCM alone does not work