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Corolla to Prius gas tank swap

Discussion in 'Gen 2 Prius Technical Discussion' started by Rivieraman71, Mar 3, 2019.

  1. NortTexSalv04Prius

    NortTexSalv04Prius Active Member

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    Please no OBD2 and dash codes
     
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  2. Rivieraman71

    Rivieraman71 Active Member

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    Good news, I’ll be swapping the tank next week. Hopefully no evap codes or problems.
     
  3. Rivieraman71

    Rivieraman71 Active Member

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    So I’m trying to figure something out with the Prius evap system. If the fuel tank pressure sensor detects pressure in the tank it throws a code for a leak in the bladder?
     
  4. NortTexSalv04Prius

    NortTexSalv04Prius Active Member

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    Okay my limited knowledge on this goes like this
    The evaporative system if has a leak is based just like the vacuum system in the average current vehicle and can be trace down using something like smoke to reveal leaking hose or connection. If the charcoal cannister has been saturated with gasoline you must replace them because the charcol canister is design for fume/vapors not full on liquid gasoline I do not know if this helps additionally I watched South main auto repair on YouTube trace down a evaporative issue on a Ford which turn out to be mainly a design flaw in the gas cap and some other gasket
     
  5. TMR-JWAP

    TMR-JWAP Senior Member

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    Intake manifold vacuum is metered to the tank and evap system to provide a partial vacuum, then closed off. Vacuum is monitored. A rapid change in vacuum level indicates a leak. If threshold is reached, DTC is set.
     
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  6. Rivieraman71

    Rivieraman71 Active Member

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    So if no pressure in the tank is read but pressure builds will that set a code?
     
  7. TMR-JWAP

    TMR-JWAP Senior Member

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    My understanding is that it's not looking for "pressure" above ambient, but for a change in vacuum after it applies vacuum and then isolates it.

    As for it setting a code if pressure builds up above ambient? I don't have a good answer for that.
     
  8. Rivieraman71

    Rivieraman71 Active Member

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    OK, reason I ask is because the tank and sending unit I have the swap has no place for a pressure sensor. The pressure sensor will be plugged into the stock Prius harness but will just be laying there . So pretty much it’s just going to be reading ambient air pressure
     
  9. Rivieraman71

    Rivieraman71 Active Member

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    I want to see if I can get away with the evap pressure sensor reading Ambient air pressure at all times And not throwing a code.That’s the only problem I see running into on the swap.
     
  10. TMR-JWAP

    TMR-JWAP Senior Member

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    I could see this possibly causing a code. It would never be able to detect the initial vacuum. That would be an indicator of a HUGE leak. I guess the only way to find out is to give it a try.
     
  11. NortTexSalv04Prius

    NortTexSalv04Prius Active Member

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    Okay this link is general knowledge after watching South Main Auto and link to this


    watch just general knowledge move to next one
     
    #151 NortTexSalv04Prius, Jul 15, 2019
    Last edited: Jul 15, 2019
  12. NortTexSalv04Prius

    NortTexSalv04Prius Active Member

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    Okay second YouTube first part about Avalon

    then the Prius evaporative diagram and bladder diagram
     
    #152 NortTexSalv04Prius, Jul 15, 2019
    Last edited: Jul 15, 2019
  13. Rivieraman71

    Rivieraman71 Active Member

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    Thank you soo much for the videos north Tex. The second one answered my question about the vapor pressure sensor. The Prius has 2 of them. I don’t see the car throwing any codes now. About to get the car on jack stands and start dropping the tank. Wish me luck!
     
  14. NortTexSalv04Prius

    NortTexSalv04Prius Active Member

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    No problem ….. the guy with NGK Technical Train YouTube (Mr. Becker) is available for questions and inquiry. …..

    My take on this the "pressure sensor" is looking and or checking for extreme movements tank pressure (to set code)..If the thresholds of high temperature are sustain and or met 95 hot side and 30 low side you will have issues ...oh these may be in C and F

    I am hoping that you can maybe post the images of the harness /connection /adapter from corolla pump to prius /corolla tank

    thank again Mr. River A Man
     
  15. Rivieraman71

    Rivieraman71 Active Member

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    Getting ready to swap the tank tonight. Don’t know if I’ll get it all done tonight but it will be done by tomorrow. I’ll try and take lots of pictures of the swap.
     
  16. Rivieraman71

    Rivieraman71 Active Member

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    18ABC531-1F31-42AC-95B9-3B445CF365A2.jpeg Let the fun begin!
     
    #156 Rivieraman71, Jul 16, 2019
    Last edited: Jul 16, 2019
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  17. Dxta

    Dxta Senior Member

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    Pls I'm very interested in this.
     
  18. Rivieraman71

    Rivieraman71 Active Member

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    Getting ready to unbolt the straps and drop the tank now. Should be out in the next 20 minutes
     
  19. Rivieraman71

    Rivieraman71 Active Member

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    So unfortunately I ran into a few problems last night.
    1. The exhaust is in the way of the tank. I’ll have to get a muffler and pipe from the resonator back off of a corolla.

    2. The Corolla tank straps won’t work. I’ll be better off using the stock Prius straps and cutting them to length. They are much more flexible and easier to work with.

    3. The check valve on top of the sending unit hits the floor and won’t allow the tank to be flush with the mounting points. It’s only half an inch too tall and right on the edge of the access hole. A slight notch will have to be cut out.

    4. The Corolla filler tube neck will have to be cut and extended with some fuel line and clamps. It’s about 2 inches too short from reaching the fuel door location on the Prius.

    5. There is a bolt that sticks out from the floor that is a mounting point for the brake line. It hits the top of the tank. It’s factory welded to the floor and had to be cut off and the brake line bent slightly to be flush with the floor. This was an easy fix.

    So nothing crazy that shuts this swap down completely but a few hiccups. I had a feeling there would be some. The car is going to have to be put back together today and I’ll source the exhaust at my local yard and this will have to be attempted again but not till October after I move and have more time.
     
  20. Rivieraman71

    Rivieraman71 Active Member

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    04432D9B-B111-4F18-8FFF-194D56BD9785.jpeg The sending unit is off a few inches from the access hole and a notch will have to be cut on the edge so the check valve doesn’t hit the floor. 0F45FF8E-D6CD-42F4-AA42-46DE36B95BBE.jpeg Here you can see the exhaust won’t clear the tank once bolted back up. CAC8D273-55B5-4D7C-8D98-F0AD743C2A1B.jpeg 5F8BBBED-F04A-4612-A1FB-0A109DC835A6.jpeg 13F15791-2D97-4962-B100-B9434F0FEE81.jpeg 8D30342B-4FA3-476F-A643-6D4394EEBA49.jpeg Figured everyone would want to see what the Corolla tank looked like. Fits the shape of the Prius floor perfect. Will have to redo this in the future and figure out the exhaust, tank straps and filler neck.
     
    #160 Rivieraman71, Jul 18, 2019
    Last edited: Jul 18, 2019