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Thread: 2010 Camaro LS3 - misfires and rough idle

  1. #1

    2010 Camaro LS3 - misfires and rough idle

    Those of you that are familar with this engine, I have a couple of questions. First off the car has the stock tune and minor bolt-ons.

    The engine has idled randomly rough since day one. Deaerlship said no codes were set so nothing is wrong. Idle is most rough, when the engine is first started in the a.m. and when I think it's swithcing from OL to CL. It also idles rough aftter getting off of the hiway and having to sit a a red light. RPMs will fluctuate quite a bit and then settle down.

    I did a bit of scanning yesterday and noticed a lot of random misfires across all cylinders. It does this at idle, a lot at decel, and some at cruise. Although at steady cruise there is almost no misfires. I'm not feeling the misfires though.

    I'm new to the LS3 and am wondering what is normal before commiting to tuning.
    2010 Camaro SS LS3
    SOLO highflow cats|VMax ported TB|Vararam

  2. #2
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    List of bolt-ons?
    07 Z06. Stock LS7 Bottom-end, Katech Torquer 110, ARH LTs w/Cats, Halltech KBII CAI w/Beehive, 160* t-stat.

  3. #3
    Quote Originally Posted by C6Z_sd View Post
    List of bolt-ons?
    Forgot to change my sig.
    2010 Camaro SS LS3
    SOLO highflow cats|VMax ported TB|Vararam

  4. #4
    Advanced Tuner eficalibrator's Avatar
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    It's more or less normal for stock LS3's. There are some interesting quirks about that combustion system (it originally came from LS7) and the factory calibration has some of its own funny business that doesn't always follow best practice at light load.

  5. #5
    Quote Originally Posted by eficalibrator View Post
    It's more or less normal for stock LS3's. There are some interesting quirks about that combustion system (it originally came from LS7) and the factory calibration has some of its own funny business that doesn't always follow best practice at light load.
    Thanks Greg! I suppose the best way to correct those issues is to throw the powertain warranty out the window and go for tuning?
    2010 Camaro SS LS3
    SOLO highflow cats|VMax ported TB|Vararam

  6. #6
    Senior Tuner DSteck's Avatar
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    Check your plugs. Dealers are notorious for starting cars, moving them fifty feet, and shutting the engine off. This is hell on spark plugs and was root cause for warranty issues concerning misfire and rough idle on multiple Chrysler platforms when I worked powertrain there.

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  7. #7
    Quote Originally Posted by DSteck View Post
    Check your plugs. Dealers are notorious for starting cars, moving them fifty feet, and shutting the engine off. This is hell on spark plugs and was root cause for warranty issues concerning misfire and rough idle on multiple Chrysler platforms when I worked powertrain there.
    I installed new plugs and MSD wires. I initially thought the plugs may be fouled because there was a lot of oil going through my PCV system due to a bad valley cover. The original plugs looks great though but I still installed the stock replacements. Thanks for the info though. Good place to start.
    2010 Camaro SS LS3
    SOLO highflow cats|VMax ported TB|Vararam

  8. #8
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    No need for the MSD wires.
    Jeramey
    Litzman Racing

  9. #9
    Quote Originally Posted by Blitzmann View Post
    No need for the MSD wires.
    I know the stock wires are fine, but long term the MSD tend to hold up to a lot more on/off proceedures. I also find them easier to put on and take off.
    2010 Camaro SS LS3
    SOLO highflow cats|VMax ported TB|Vararam

  10. #10
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    Quote Originally Posted by IndeedSS View Post
    Those of you that are familar with this engine, I have a couple of questions. First off the car has the stock tune and minor bolt-ons.

    The engine has idled randomly rough since day one. Deaerlship said no codes were set so nothing is wrong. Idle is most rough, when the engine is first started in the a.m. and when I think it's swithcing from OL to CL. It also idles rough aftter getting off of the hiway and having to sit a a red light. RPMs will fluctuate quite a bit and then settle down.

    I did a bit of scanning yesterday and noticed a lot of random misfires across all cylinders. It does this at idle, a lot at decel, and some at cruise. Although at steady cruise there is almost no misfires. I'm not feeling the misfires though.

    I'm new to the LS3 and am wondering what is normal before commiting to tuning.
    So it did this when 100% stock? Reason I ask is I had a customer that had removed the lower part of the air filter box along with the air filter on a 10 Camaro LS3. All he was running was the upper part of the air filter box. The car was idling rough and even surging. I find these new style MAF sensors are very sensitive to what is upstream of them. When he reinstalled all the air filter parts and the filter the idle went back to being dead smooth. Was just wondering if your CAI may be causing some of the problem.

    I just spent hours trying to get a LS3 480hp GMPP crate motor (LS3 with a GM Hot Cam) in a 79 T/A to idle. This car wouldn't even come close to running on the stock tune that came with the crate motor. Turns out most of the problems were in the tube and location of the MAF and air filter getting everything to fit in the 79 T/A. We changed some of it around and made it idle better, but still not perfect.

  11. #11
    Quote Originally Posted by 2xLS1 View Post
    So it did this when 100% stock? Reason I ask is I had a customer that had removed the lower part of the air filter box along with the air filter on a 10 Camaro LS3. All he was running was the upper part of the air filter box. The car was idling rough and even surging. I find these new style MAF sensors are very sensitive to what is upstream of them. When he reinstalled all the air filter parts and the filter the idle went back to being dead smooth. Was just wondering if your CAI may be causing some of the problem.

    I just spent hours trying to get a LS3 480hp GMPP crate motor (LS3 with a GM Hot Cam) in a 79 T/A to idle. This car wouldn't even come close to running on the stock tune that came with the crate motor. Turns out most of the problems were in the tube and location of the MAF and air filter getting everything to fit in the 79 T/A. We changed some of it around and made it idle better, but still not perfect.
    Yes, my car has idled rough even when completely stock. One of the intake manufacturers discovered there were some "weak" MAF sensors from the factory and why some people had bucking after installing their intake. These sensors would meet GM standards but didn't do well in less than stock enviroments. The weak sensors had a letter ie P, where as the stronger sensor had a letter and one or two digit number ie K1 or K23. Switching to a K9 sensor cleared up the bucking. They quoted the hz ranges where they were able to scan and see the difference. I was luckier than most and already had a K21.
    Last edited by IndeedSS; 05-23-2011 at 12:38 PM.
    2010 Camaro SS LS3
    SOLO highflow cats|VMax ported TB|Vararam

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    manual spark smoothing gives it that lope without the cam

  13. #13
    Senior Tuner DSteck's Avatar
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    Quote Originally Posted by 2xLS1 View Post
    I just spent hours trying to get a LS3 480hp GMPP crate motor (LS3 with a GM Hot Cam) in a 79 T/A to idle. This car wouldn't even come close to running on the stock tune that came with the crate motor. Turns out most of the problems were in the tube and location of the MAF and air filter getting everything to fit in the 79 T/A. We changed some of it around and made it idle better, but still not perfect.
    Yea, the tune that comes with that engine is complete junk. The MAF gets real sensitive with it for some reason too.

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  14. #14
    I guess to be completely happy a tune is going to be necessary.
    2010 Camaro SS LS3
    SOLO highflow cats|VMax ported TB|Vararam

  15. #15
    Senior Tuner DSteck's Avatar
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    Personally, I don't like idling an engine at 525/550. Even a stock cam will have some "vibration" to it. My TBSS idles at 600 in gear and feels pretty rough, and tons of people complain about it.

    DSX Tuning - St. Louis, MO
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    http://www.facebook.com/dsx.tuning
    Just say no to bull s***.
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  16. #16
    Quote Originally Posted by DSteck View Post
    Personally, I don't like idling an engine at 525/550. Even a stock cam will have some "vibration" to it. My TBSS idles at 600 in gear and feels pretty rough, and tons of people complain about it.
    I see what you are saying. I've heard quite a few complain about the low stock idle from others as well. You think raising it 50 or so might get rid of the occasional feel that it's going to die? The good news is that the car only shakes for a few seconds and then settles down for the most part.
    2010 Camaro SS LS3
    SOLO highflow cats|VMax ported TB|Vararam

  17. #17
    Senior Tuner DSteck's Avatar
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    Find somebody with a scanner and push the idle speed higher... see how it feels.

    DSX Tuning - St. Louis, MO
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  18. #18
    Senior Tuner IDRIVEAG8GT's Avatar
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    07 Silverado with a V-Max stock? Notorious to shake at a red light. The idle is too slow fer sure, and if your foot is sensitive enough you will feel it in your brake pedal due to vacuum fluctuation. I would tune it, and also you said that the TB is ported? I would think that that would make the issue more apparent since generally that tends to change the MAF coefficients somewhat. What altitude are you at?
    Gray Ghost- The abomination. 2007 Chevrolet Silverado CCSB. 98mm turbo, nitrous, 428LSX, Rossler 80E with a brake. Finally finished. 23 psi, no numbers, Slow as hell.

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  19. #19
    Di-electric grease used on the plug end of the wires? Fill the end of the boot up and click it back on. That has solved our issues on 95% of misfires we see on stock to mild engines.
    2001 Z06 - 417 LS3 - LPE CNC LS3 heads - LPE GT-11 cam - ARH 1 7/8" - LPE C6 intake - RPM 3.73 diff - tuned with HP Tuners
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    Are you using Iridum plugs? If so, throw them away.
    07 Z06. Stock LS7 Bottom-end, Katech Torquer 110, ARH LTs w/Cats, Halltech KBII CAI w/Beehive, 160* t-stat.