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Thread: Turbo LQ9 3Bar Wont idle plz help

  1. #1
    Tuner in Training
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    Jun 2016
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    Angry Turbo LQ9 3Bar Wont idle plz help

    Looking for pointers/help

    I have tuned countless NA cars before but this is my 1st custom OS turbo tune and I'm stuck.

    This is a 2007 Silverado with a 6.0 LQ9 that was NA with bolt-ons and a TSP mild NA cam a while back. I tuned it while it was NA and it ran flawlessly. Owner installed a custom turbo kit (GT45 turbo) FIC "Fuel Injector Connection" 850CC injectors and a ZR1 3bar map sensor the other day. I installed the custom 2bar SD OS, Scaled the injectors, and input the data that was given to me by FIC. Copied the stock VE tables and scaled them back a bit to comp for the bigger injectors. Bumped the idle up just a bit more yet it will not idle!! I tried adding min base airflow but it doesn't help. I played with the Idle timing and base idle settings and still no idle. I tried adjusting the VE tables around idle but cant get it to hit the AFR target. It will catch idle for about 10sec sometimes then start to surge then die(if I hold the gas pedal lightly to stabilize its ok). MAF is failed and not even installed, new IAT sensor is working fine. I tried to get my AFR leaner at idle but every time it would overshoot my target or undershoot my target, and when it did get close to target it would break up. Its if it doesn't like running above a 13.5 AFR at idle

    I'm at a loss and know I'm missing something, just not sure what? Can anyone be so kind as to look over this tune file and datalog and let me know what they think?
    Attached Files Attached Files

  2. #2
    Tuning Addict 5FDP's Avatar
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    If the injectors are larger than the 63.5lb/hr like they are you need to use the double stoich, half the IFR and half the IVT terms to correctly scale the injectors.

    It's much less hassle to do it this way, then you can work the VE as normal with no scaling and jumping hoops to get it run good.
    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
    Tuner in Training
    Join Date
    Jun 2016
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    I used the tuning schools method for the scaling. But I will do this method instead. Thank you!

    1 more question. Do I have to rescale any lables on any tables so they match the 3bar? If so which ones? Ive been told spark tables are one of them. How do you go by doing that? Any how to's you know of?

    Thanks in advance!!!