Occasional piston slap upon Atkinson startup.

Discussion in 'Gen 4 Prius Care, Maintenance and Troubleshooting' started by DonJuan1943, Jan 20, 2021.

  1. DonJuan1943

    DonJuan1943 Member

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    I've been rolling around this site for a while, and have gotten some good advice and help from my fellow Prius hooligans. 2016 Prius 3, 27,000mi. grey. Indoor kept. Bought new. Religiously changed oil at dealer. Here's the Q: Occasionally. ...(not every time), when the Atkinson starts, I'll hear a piston slap that lasts a millisecond. Then the Atkinson purrs on silently without issue; both under power and at idle. I started noticing this phenomenon about a year ago. Mentioned it to service rep. at oil change time. No response or data that he could find. Anyway; I thought I'd bring it up here to see if any of you fraternity fellows and gals might have some useful input. Thanks.
     
    #1 DonJuan1943, Jan 20, 2021
    robsnyder20 likes this.
  2. bisco

    bisco cookie crumbler

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    did he hear it?
     
    #2 bisco, Jan 20, 2021
  3. DonJuan1943

    DonJuan1943 Member

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    No. But he typed-in the narrative of my description of the complaint in the record for future reference. Thanks for your response. An aircraft mechanic friend who knows the car suggested that it may be indicative of minor carbon buildup from excessive "granny short-trip use". He suggests putting half a tank of premium gas in it, and taking it for a highway trip and blow the cobs out. I haven't tried that yet.
     
    #3 DonJuan1943, Jan 20, 2021
  4. bisco

    bisco cookie crumbler

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    do you think it would record well?
     
    #4 bisco, Jan 20, 2021
  5. robsnyder20

    robsnyder20 Active Member

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    I have heard it on mine. Ran some premium fuel, some Techron cleaner and took off the air pipe and sprayed throttle body cleaner in it. Still get it very occasionally but it "seems" to happen very few startups. My coworker had a 2010 corolla with 150k miles and his would make the same exact noise almost every cold start up but he never worried about it. If someone else has a better fix, please let us know. I have 80k on mine but noticed it a quite a bit (like 1 of 5 every cold start ups) at 60k. I am guessing I should have a fuel system service done at the dealer that have been pushing me to do but I prefer to do my own servicing as much as possible.
     
    #5 robsnyder20, Jan 20, 2021
  6. roadwarrior28

    roadwarrior28 Member

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    I'm very curious if the Italian tuneup makes a difference :D keep us updated
     
    #6 roadwarrior28, Feb 13, 2021
  7. Mendel Leisk

    Mendel Leisk Senior Member

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    US schedule is 10k miles or yearly, whichever comes first. Are you following both criteria, or just the miles?

    Guesstimating you’re doing 5k~ miles a year; that would entail a fair amount of short trips, arguably qualify as “severe service”, and for that the schedule recommends to double up: 5k miles or 6 months.
     
    #7 Mendel Leisk, Feb 14, 2021
    Last edited: Feb 14, 2021
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