2012 Si rev problem

Discussion in '9th Generation Civic General Discussion' started by Dmpjr1, May 4, 2019.

  1. Dmpjr1

    Dmpjr1 New Member

    Messages:
    7
    Hey all, I have a 2012 SI with no mods and about 70,000 miles on it. The issue I am having is when the car is running at temp it starts to rev up and down on it's own after i let off the gas; while shifting gears when the clutch is pressed the rpms stay where they were when i pressed the clutch, takes about two seconds for them to drop off. And while driving in low gears, 1 or 2 through a parking lot and such the car jerks a lot when rpms drop down after letting off the gas. I checked the MAF sensor and that seems to be fine, I've heard it could possibly be idol air control valve but before I start ripping things apart I'd see if any of the people in the know may be able to shed some light on this. Thanks!
     
  2. mySIck

    mySIck Well-Known Member

    Messages:
    1,247
    Location:
    FT. Bragg, NC
    Vehicle Model:
    Civic SI
    Body Style:
    Sedan
    It only does it once you press in the clutch for a few seconds and goes back to normal?
     
  3. Dmpjr1

    Dmpjr1 New Member

    Messages:
    7
    it does that when i shift, but when i stop or have it in neutral it revs up and down from 2500 rpm down to 1000 several times before it levels out.
     
  4. webby
    • Staff
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    webby Administrator

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    49,993
    I’d check your idle air control valve and your throttle body. Clean them out and see if you have any change.
     
  5. Dmpjr1

    Dmpjr1 New Member

    Messages:
    7
    Yeah that is what i was seeing most from my research, I'll probably just have to do that regardless and go from there. Thanks for the post
     
  6. mySIck

    mySIck Well-Known Member

    Messages:
    1,247
    Location:
    FT. Bragg, NC
    Vehicle Model:
    Civic SI
    Body Style:
    Sedan
    Mine started doing something similar today I was going to do what webby mentioned and clean the TB and IACV.
     
  7. Dmpjr1

    Dmpjr1 New Member

    Messages:
    7
    Yeah that seems to be the best course of action, if you notice anything else let me know I probably won't be able to tackle it until next week
     
  8. dpetro1

    dpetro1 Well-Known Member

    Messages:
    410
    Location:
    Catonsville, MD
    What is this idle control valve everyone is talking about?
    This was a common problem on older Hondas but I'm pretty sure there is no such part on the 9th gen si.

    Sent from my SM-G920V using Tapatalk
     
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  9. webby
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    webby Administrator

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    I never even noticed or looked it up till now. It appears it’s electronically controlled on the throttle body on the si?
     
  10. mySIck

    mySIck Well-Known Member

    Messages:
    1,247
    Location:
    FT. Bragg, NC
    Vehicle Model:
    Civic SI
    Body Style:
    Sedan
    Yea I just noticed that to. Bad thing is I have taken my TB off a few times now.
     
  11. Dmpjr1

    Dmpjr1 New Member

    Messages:
    7
    Good call, looks like the valves stopped in 2011. Did cleaning the TB help your problem mySIck?
     
  12. dpetro1

    dpetro1 Well-Known Member

    Messages:
    410
    Location:
    Catonsville, MD
    Right, the entire throttle body is electronically controlled. The IACV was an electronic control for cable driven TB.
    As for the OPs problem, you can try to clean the the TB but I would also check some general maintenance items first.
    Is your air filter clean, coolant level full? Any potential vacuum leaks or cracked hoses?

    Sent from my SM-G920V using Tapatalk
     
  13. mySIck

    mySIck Well-Known Member

    Messages:
    1,247
    Location:
    FT. Bragg, NC
    Vehicle Model:
    Civic SI
    Body Style:
    Sedan
    I tried cleaning the TB it was not all that dirty on mine. I believe mine is a vacuum leak somewhere or possibly something with my tune. Mine only bounces up to 2,000 and right back to idle.
     
  14. Dmpjr1

    Dmpjr1 New Member

    Messages:
    7
    Air filter is clean and hoses look good, I’ll do a vacuum leak next, I saw a video showing a couple ways to do it so hopefully it goes alright. Thanks for the input!
     
  15. Dmpjr1

    Dmpjr1 New Member

    Messages:
    7
    Yeah that's understandable and not too far off from what mine does. I have no tunes so I’m thinking mine might be a vacuum leak then. Good luck to you
     

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