2010 with JDM 30k engine just installed ... Rough idle Help :)

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by Ticklefishdude, Jun 16, 2020.

  1. Ticklefishdude

    Ticklefishdude Junior Member

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    Just finishing installing a newer JDM engine into a 2010 Prius I picked up with a blown engine/rod. I started it up this weekend and it idles VERY rough. Did not let it run long. I changed the oil and it looks completely clean and engine looked like new when purchased. I used the intake, EGR etc from the new engine. Any recommendations on what to look for or try? I don't think it is a gasket issue, at least I hope not. Had a 2005 that has been indestructible and thought I would just upgrade to the 3 ... not sure now. Rest of car is perfect. Thanks!! John
     
    #1 Ticklefishdude, Jun 16, 2020
  2. bisco

    bisco cookie crumbler

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    no trouble codes?
     
    #2 bisco, Jun 16, 2020
    Raytheeagle likes this.
  3. Raytheeagle

    Raytheeagle Senior Member

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    All hoses and connections are tight?

    How did the plugs look in the new engine?
     
    #3 Raytheeagle, Jun 16, 2020
  4. Greenteapri

    Greenteapri Active Member

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    If you don't have any faults displaying, what if you let it run through?

    I've had a couple scenarios of rough idles. The last time it happened was a few months ago after I installed new struts. It scared the bajebus out of me! I turned the car off immediately and checked my work again. Once I reverified everything was buttoned up, I fired her up again. She ran terribly rough for eight agonizing seconds but eventually smoothed out. It's weird because I didn't touch the engine.

    The first time it happened was directly after a spark plug change. I did the same thing. Turned off, rechecked my work and fired her up. She smoothed right out after a few seconds.

    How's the oil?
     
    #4 Greenteapri, Jun 16, 2020
  5. Ticklefishdude

    Ticklefishdude Junior Member

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    Sometimes I amaze myself at the things I space out :( while trying to be meticulous... I noted that when I put the new engine in that I did not put a donut on the exhaust manifold flange so while it seated enough to not sound like a Harley, I am sure that has a lot to do with it. Will do that this week and update. Thanks guys.
     
    #5 Ticklefishdude, Jun 17, 2020
  6. Ticklefishdude

    Ticklefishdude Junior Member

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    Oil was clean and not milky. I just changed that as well. Will fix exhaust donut issue then go from there :)
     
    #6 Ticklefishdude, Jun 17, 2020
  7. Ticklefishdude

    Ticklefishdude Junior Member

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    Fast forward with all the Covid stuff going on and not needing a car as much :) I replaced the exhaust donut. Drove car a little. Got rough and shaky. OBD reader shows a P0403 code. Question, I opened up the EGR cover. Looks brand new but should I manually be able to open and close the valve by pushing and pulling on the stem? It is completely stuck. Thanks for your input! John
     
    #7 Ticklefishdude, Jul 20, 2020
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