First start after engine rebuild

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by Wtfdustinwtf, Mar 28, 2026.

  1. Wtfdustinwtf

    Wtfdustinwtf Junior Member

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    Hello, did an engine rebuild its all back together gonna fire it up tomorrow. My AI said I should pop put the ignition coils and try to start it for several seconds, pause a minute, try for several more seconds. I understand with standard engine cars this works great. Does this work for the prius system though?

    Also while I'm making a post what's it like to try to start a pushbutton car with ignition coils out? I just keep holding it or something? I don't have experience with first startups after rebuild and am trying to get a feel for how it will go. I assume the fuel pump will get gas going through the fuel line pretty quickly even though I drained the lines right? Thanks
     
    #1 Wtfdustinwtf, Mar 28, 2026
  2. Tombukt2

    Tombukt2 Senior Member

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    With the spark plugs out you could just turn the crankshaft with your electric wrench it only has to go about maybe a hundred RPMs with plugs out should be easy it'll prime oil pump . Not as important as it was 30 yrs ago for sure
     
    #2 Tombukt2, Mar 28, 2026
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  3. ASRDogman

    ASRDogman Senior Member

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    You'll get a lot of error codes, and the engine likely will only turn over for a few second, then stop.
    As long as you have oil in the engine, and coolant in the system, and all is back together, start it
    like you normally would.
    It will take a few seconds before it starts, and if all is well, it will run normally.


     
    #3 ASRDogman, Mar 28, 2026
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  4. rjparker

    rjparker Tu Humilde Sirviente

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    It might rattle for a few seconds since the variable timing is not seeing oil pressure but should run unless the usual vacuum line, pcv valve or electrical connector is off.

    Even then it will "sound" like it ran because of the high speed cranking people have not heard before. "It ran for ten seconds and quit".
     
    #4 rjparker, Mar 28, 2026
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  5. Wtfdustinwtf

    Wtfdustinwtf Junior Member

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    FYI for anyone in the future reading this the first start up sounds scary as can be. All sorts of knocks tics thumps. It goes away pretty quickly. If advice turning yout prius on to ig-on to run codes first to make sure everything is fine before turning the car. Start it in maintenance mode to go ahead and burp the coolant. Except some funky sounds though. On my second start there was only one brief sounds and now it starts normal
     
    #5 Wtfdustinwtf, Apr 1, 2026
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  6. ASRDogman

    ASRDogman Senior Member

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    Is all working now?
     
    #6 ASRDogman, Apr 1, 2026
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  7. Wtfdustinwtf

    Wtfdustinwtf Junior Member

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    Yes! I haven't done a long drive yet but I did do a 40 minute maintenance mode followed by several short trips. Next step is drive around my area in circles for 25 miles. No leaks or issues detected. I caught some hell trying to hook the double wiring harness back into the passenger side of the inverter but I eventually figured how to get it to click in.
     
    #7 Wtfdustinwtf, Apr 1, 2026
  8. Mendel Leisk

    Mendel Leisk MMX GEN III

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    @Ragingfit, after doing his engine transplant, did something, disabled injectors or something, and put the car in start up mode for several seconds. Basically with the aim of getting oil pressure up. I believe he also had a multimeter on something, the oil pressure sensor maybe.

    Yeah, see last video here:

    Swapping in a Gen 4 Prius' 2ZR Engine into the Prius v | PriusChat

    About 6 minutes in.
     
    #8 Mendel Leisk, Apr 1, 2026
  9. ASRDogman

    ASRDogman Senior Member

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    Glad to hear it! I'm happy for you!



     
    #9 ASRDogman, Apr 1, 2026
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