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Knocking, misfires at startup

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by Josh Bunzel, Mar 1, 2022.

  1. Josh Bunzel

    Josh Bunzel New Member

    Joined:
    Feb 20, 2022
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    Location:
    las Vegas
    Vehicle:
    2013 Prius
    Model:
    Three
    I know there are numerous threads open about such issues, and I've read a number of them. I figured it would be better to start a new thread, though, instead of piggybacking on another.

    My 2013 Prius Gen 3 with 266k miles on it started doing some intense rattling/shaking at startup about a week and a half ago. It was on startup but also when accelerating from some stops. It started rather suddenly too. It also threw a P0302 code (misfire on cylinder 2).

    I started with replacing all spark plugs and the coil on cylinder 2. Still knocking. But only on initial starts now. I put the original coil back in, no change.

    I found posts on the T-SB 0012-10 referring to a defective intake manifold under those exact conditions. So, I replaced the intake manifold, cleaned the engine intakes thoroughly, cleaned the PCV valve, and did a precursory EGR cooler cleaning (it could use more cleaning, I was eager to get it back on to test for head gasket failure). The EGR was pretty clogged up, again, got a good amount out.

    The old intake had a fair amount of milky liquid at the bottom. But I read this is normal.

    Still knocking. Much less severe. Only on some startups. No codes but monitoring it at startup shows there are still misfires on cylinder 2 on startup (just not enough for a code?).

    The coolant level was a little below low when the knocking first started. I don't know if it had been like this though. I've since topped it off and seen no noticeable drop.

    I also did a block test/combustion leak test. I put the tester on the ICE coolant reservoir, ran the car up to 190 coolant temp, and did the test. Pumped for two minutes. The liquid was still blue.

    I also peered down each cylinder (plug and coil removed), each looked dirty. I read that if you have "steam cleaned" cylinders it's a sign of head gasket failure since burning coolant cleans the cylinders.

    I'm on the verge of taking it to a shop for further diagnosis. Going to talk to a family friend mechanic later today but looking for other things to check. Someone mentioned a leak-down test. I'm not sure where to get that equipment. I rented the block tester from O'Reilly, I didn't see any leak down test equipment for rent.

    I've somewhat come to terms with the idea of it maybe being the head gasket. But I can't confirm it. If it is, probably going to sell the car. I would love to attempt a head gasket replacement but I don't have the time or space (I live in an apartment complex). I'm leaving the country in 4-5 months and my motorcycle will do just fine for me until then.
     
  2. Josh Bunzel

    Josh Bunzel New Member

    Joined:
    Feb 20, 2022
    6
    4
    0
    Location:
    las Vegas
    Vehicle:
    2013 Prius
    Model:
    Three
    Update to this while I've been waiting for it to be approved:

    I took a look at the fuel injectors. Looking at just the electrical plugs, the one for cylinder 2 was damp with what looked like oil. The other three were dry.

    I removed the injectors for cylinders 1 and 2 and swapped them. All of them had a fair amount of crud built up around the nozzle/shaft, but cylinder 2's was noticeable worse. Gave both a wipe off on the tip before putting them in.

    I will add that when I started the car again there were some misfires on 1, 2, and 4. I'm wondering if it may have had something to do with the fact that when I removed the first injector for swapping, the fuel rail was emptied.
     
  3. tankyuong

    tankyuong Senior Member

    Joined:
    Nov 9, 2012
    1,555
    661
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    Location:
    Central MO
    Vehicle:
    2012 Prius c
    Model:
    II
    I think your head gasket is toast