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Gen4 to Gen3 engine swap using gen 4 intake and egr, DONE!

Discussion in 'Gen 3 Prius Technical Discussion' started by Dave Hanson, Aug 13, 2019.

  1. Alexander D

    Alexander D Junior Member

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    If I remember correctly, to swap to the gen 4 intake you need to do several things.
    1. Reroute and replace the plug for the map sensor (one has 3 wires the other has 4)
    2. extend wires to throttle body
    3. trim or modify a bunch of stuff to get 3rd gen air box to fit
    4. Move the vacuum switch out of the way of the air box/intake and extend the vacuum tube and the wires
    5. Add a bracket to help mount the air box
    6. probably way more stuff

    Or you can just use the 3rd gen intake... much much easier, I would recommend. Makes the air box and all the wires fit their original locations.
     
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  2. ASRDogman

    ASRDogman Senior Member

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    Dave: Update?
    How's the Gen4 working? Any problems?
     
  3. Dave Hanson

    Dave Hanson Member

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    Sorry for the delay, my wife and daughter had the car on a trip and I wanted to check the code it set after they left. Multiple cylinder misfire, been setting that one from time to time, usually when you floor it. Not sure why, because it normally runs fine. Gets about 45mpg, which is about the same as the old engine. Same catalytic converter probably not helping that. Has about 12k on the swap and is now my daughter's. I found a great deal on a 2017 prius two with 186k miles for $7100, so we both have 2017 engines but hers has 80k less miles.
     
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  4. Carlos De Castro

    Carlos De Castro New Member

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    @Dave Hanson I wish there was a youtube video on how the new 4th gen egr setup is done. Also, since now that I'm seeing it's been 3 years since the last post, how's the car running now? Thanks for the diagram, I'll try my best to use it; I'm just more of a visual person.
     
  5. drbtz

    drbtz Member

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    Well since we're gonna Necro this thread, how the gen4 going Dave? Cylinder codes ever stop coming back? Hope the daughter is enjoying her ride and that you '17 is still kicking strong
     
  6. Dave Hanson

    Dave Hanson Member

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    Still running strong, now it has 24k since swap and aside from the occasional multiple cylinder misfire code, it's been problem free. Last reset code about two months ago. She's going to Minneapolis today for a concert and shopping for her and my wife's vintage clothing shop.
     
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  7. Carlos De Castro

    Carlos De Castro New Member

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    dude thanks a bunch for the reply... also real quick question on the diagram... is the thermostat valve something visible that I'm supposed to move or is that just showing that line has the thermostat valve? Thanks
     
  8. Dave Hanson

    Dave Hanson Member

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    Only red things are new, so the valve it's self stays put, just connect to the lines on the firewall.
     
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  9. Carlos De Castro

    Carlos De Castro New Member

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    got it thanks!
     
  10. zinzet

    zinzet Junior Member

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    Hi. Did you fix P0401 issue? If yes don't you mind sharing. I also have P0401 after installation gen4 engine to gen3.
     
  11. Debo160

    Debo160 Junior Member

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    We didn't do this. This might be the problem to my issues. Did you just cut the wire and resolder them, Or did you use pull them out of the connector. The car run and drives but there are little issues going on. This could really be the solution. I also have a P2237 and a P0031. Hopefully these are the last 3 things.
     
  12. ChapmanF

    ChapmanF Senior Member

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    Nope nope nope nope nope nope NOPE. We've known for a couple years now that EGR wire swap business was bogus. See this post here for more.

    There is no electrical pinout difference between the Gen 3 and Gen 4 EGR valves, and doing that swap simply makes the EGR not work.

    This idea won't stop rising again and again from the dead. Help put a stake through it.
     
    Mendel Leisk likes this.
  13. Debo160

    Debo160 Junior Member

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    Ok thank you I was ready to jump on in. I guess
    Oh wow. OK. I was ready to jump right in and swap those wires. The car runs pretty good but still struggles

    to me on the highway. It seems like the rpms are still high. So most of my driving is in city. Im also getting

    terrible gas milage for a Prius. Avg my 36mpg. Im guessing the next step is to swap out the 2 sensors for

    P2237 and a P0031 and she what happens next. It's differently been a long run with this one.

    All this goes on and my ABS actuator and water pump go bad in my 07. But were still here lol.