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Thread: 6.0LS Engine Idle Issue - 2007 Chevy Silverado

  1. 08-21-2020 #1
    Rare87GT
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    6.0LS Engine Idle Issue - 2007 Chevy Silverado

    My buddy just got done installing a 6.0 LS engine with a large cam. Cam specs are: BTR Stage 4 Truck Cam - .553/.553 with 109 lob separation angle. We had a few dyno runs on the truck a few weeks back but also trying to get the idle set correctly or lower than 1000. Closer to 800 or so. And also it seems that the truck idle does not want to lower or go down like it should...seems to hang up when reving it up, doesn't drop correctly. Can someone look at this tune and see why or what needs to happen in what settings to lower the idle and also get it to drop like it should? He is running a 102mm throttle body, cam, headers and exhaust and basically stock heads. It isn't as easy as just changing the idle speed like my 3800sc car where I can just go command an idle rpm and be done. Please let me know. Thank you.
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  2. 08-21-2020 #2
    5FDP
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    That's because there are airflow and fueling tables you need to work with, like the base running airflow. As well as idle timing.

    Too much timing and too much spark correction will cause the idle to not be steady or want to settle down. The over/underspeed spark correction in this tune could swing it -18 to +22 degrees, cut that way down to +/- 8 degrees. Get the idle timing down around 18-20 degrees.
    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.
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  3. 08-23-2020 #3
    Rare87GT
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    What is the easiest way to lower the idle from where it is at right now? Right now it is steady at 950-1000rpm. Trying to get it closer to 800 or so. If anyone can take a peek at the tune I posted and see any initial ideas that would be great. We had a dyno run on the truck a few weeks ago, but we had to change throttle body's due to some issues with the idle and truck dying. The truck does not die now but it also won't calm down on the RPM.
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  4. 08-23-2020 #4
    Jon S.
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    5FDP gave you some basic advice in post #2.

    Getting the engine to idle well, and return to idle well, with a camshaft that has a 109 degree lobe separation angle may be a challenge. Getting it to idle below 900 RPM may be a challenge. Many of the 102 mm cable throttle bodies are junk - so that may also add to the challenge.

    Time to hire a knowledgeable tuner.
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