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Chasing a vacuum leak

Discussion in '60-Series Wagons' started by mwebfj60, Sep 14, 2017.

  1. mwebfj60

    mwebfj60 SILVER Star

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    On a side note, after adjusting valves and tweaking carb, I'm now pulling a steady 21" at idle.
     
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  2. OSS

    OSS SILVER Star

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    21" is what mine pulls at idle too (sea level, overhauled head with new everything, flat manifold & new gaskets).

    That's something, an open vacuum pipe like the AC idle up fitting only drops the vac 1". And that's a big vac leak. My engine doesn't sound quite right when I pull that hose (playing around). Only 1" drop & somethings not right.

    Something to remember...
     
  3. 4Cruisers

    4Cruisers SILVER Star

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    For those at altitude like me (7,240 feet) the sea level vacuum adjusted for altitude is only about 15.2", so I'm doing good when I hit that point.
     
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  4. NeverGiveUpYota

    NeverGiveUpYota Dare me. SILVER Star

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    @Cruiser Jimmy can we make this thread a sticky for searching all possible sources for vac leaks? I just looked through and unless I missed one, there isn't one at all.
     
  5. Cruiser Jimmy

    Cruiser Jimmy Moderator

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  6. FJStan

    FJStan

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    Thanks CJ!

    I’m in the process of searching and correcting vacuum leaks and I came across this valve with a strange set-up which I have not been able to verify in the FSM.

    Can anyone guide me on how the set-up should actually be, if this is incorrectly connected - appears to be connected to itself.

    0BCFA336-1B7B-4DDA-9338-5CF240A2F0E5.jpeg
     
  7. 4Cruisers

    4Cruisers SILVER Star

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    That's the set-up for venting your distributor cap. I'll try to dig up the diagram from the FSM. IIRC the large hose coming out of the side should attach to the top of the distributor cap, the large hose coming out of the top (via the tee) should attach to the underside of the air filter housing, and the bottom vacuum hose should connect to the gas filter fitting on the top of the intake manifold.

    Check out my Post #14973 on this page (from my '76 FJ60 distributor upgrade):

    page-749

    Here's the diagram:

    VCV Diagram.png
     
    Last edited: Oct 19, 2017
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  8. FJStan

    FJStan

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    Thank you for this. If I’m looking at this diagram correctly, the T fitting is on the wrong hose. Looks like it should be on the hose going to the air cleaner.

    Thanks for including a link to your post confirming my understanding above.

    Ticking away one more problem.

    Thanks!
     
    Last edited: Oct 19, 2017
  9. NeverGiveUpYota

    NeverGiveUpYota Dare me. SILVER Star

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    Unless I'm off... this is how my passenger vcv is hooked up.

    IMG_8329.JPG
     
  10. FJStan

    FJStan

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    Right...so your setup and mine are identical and apparently not correct - per the diagram above.

    4Cruisers seems to have the correct set up. See image below - from his post

    3D0B0DC7-BE83-4A35-9819-02907F90F27D.png
     
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  11. NeverGiveUpYota

    NeverGiveUpYota Dare me. SILVER Star

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    Hilarious. I was gonna say if I was off someone would pipe in. I've had everything off and on way too many times you'd think it would all stick. Duh.
     
  12. mwebfj60

    mwebfj60 SILVER Star

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    4cruiser's drawing is correct as per the FSM drawing pg 3-3 of the Emission Manual.

    I have had mine hooked up with a T on X and Z with Y going to the air cleaner this whole time. Taking a closer look at this led me down another rabbit hole. After sleuthing, I'm keeping my setup as is.

    The VCV
     
    Last edited: Oct 20, 2017
  13. FJStan

    FJStan

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    Okay, so....I redid my set-up and moved on to replacing some old vacuum lines and to test the several valves that operate the system. I then came across the mother of all vacuum leaks - between the intake manifold and the block !!! At this point I’m done diagnosing anything further until I can replace the gaskets.

    I may move on to a different thread relating to this particular service, since I’d like to tackle it myself.
     
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  14. mattressking

    mattressking

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    However if you look at the vacuum diagram via the parts diagram, it is not the same. Mine has been setup according to the diagram below.

    [​IMG]
     
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  15. mattressking

    mattressking

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    Figured my question/curiosity might fit best here. Just put on a new gas filter on the manifold last night and when fitting, I was curious if the tapered threads were sufficient to seal the threads when tightened.

    Does anyone use teflon when installing the gas filter? My assumption is that if Toyota wanted additional sealant, it would be pre-applied or noted somewhere in the fsm.
     
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  16. mwebfj60

    mwebfj60 SILVER Star

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    That's a great diagram.

    As long as you have either Y or Z going to the air cleaner and the S hooked to manifold vac, it operates the exact same while running.

    The only reason I used Y to the air cleaner in the first place is that Y is closed with no vacuum to S while X and Z flow air between each other. To keep any fuel vapors from making its way into the distributor when the engine isn't running this seemed the best way.
     
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  17. FJStan

    FJStan

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    Awesome diagram. Can you share the link to that parts manual — PLEASE? I’d love to have that in higher res to print it out.

    Thanks so much.
     
  18. OSS

    OSS SILVER Star

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    Major Edit>

    The plumbing schematic in the emissions FSM is incorrect for the distributor vent VCV ... but Toyota didn't follow that plumbing diagram when the distributor venting VCV hoses were installed. Pipe Z should Tee off with pipe X.


    And as had been posted above, this picture is plumbed incorrectly.

    image.png


    The most important function of the VCV is to completely seal off the distributor from the air cleaner housing. The only way to do that is to have only pipe Y connect to the air cleaner housing like this picture below.

    This picture has the hoses routed correctly
    image.jpeg
     
    Last edited: Oct 25, 2017
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  19. chichiflys

    chichiflys

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    Holy cow - you just saved me $80. I ordered (hopefully it's in stock and on the way) a new VCV for my dizzy side and was going to hook it up the way I thought it was supposed to be - which, apparently is not right ...thanks man!
     
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  20. mwebfj60

    mwebfj60 SILVER Star

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    Gotta respect the knowledge of @OSS. Good stuff.

    So with the edit above, the below is irrelevant.

    Now let me throw a wrench in the debate...

    The only problem with that is, X and Z flow air when there is no vacuum on S. Y is the only port that is isolated and closed with no vacuum on S....so, if you really wanted to keep the ozone from reaching the VCV, you would have to plumb Y directly to the distributor vent and run a T with X and Z going to the air cleaner.
     
    Last edited: Oct 25, 2017
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