Intake Problem (I6 Engine)

Discussion in 'Technical' started by mrmclargehuge7, Apr 9, 2010.

  1. mrmclargehuge7

    mrmclargehuge7 Member

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    There are three hoses coming out right under the carb they are fairly small. Problem is where the third hose should be it is gone. It was missing when I got the car so i have an open spot where I should have a hose and you can hear it really loud sucking in air but im not sure where it should connect to. If someone could tell me where the three hoses go or a picture of their straight six it would be greatly appreciated. Thanks
     
  2. rthomas771

    rthomas771 Member

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  3. mrmclargehuge7

    mrmclargehuge7 Member

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    The port you have the tube coming out is the one i dont have a tube for. I tried plugging but car has trouble even idling and dies. Where does the port on yours connect to? Thanks
     
  4. indyman13

    indyman13 Member

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    Two of the three tubes coming off the manifold vacuum shown in rthomas771's photos should go to a pair of hose connectors in the middle of the firewall. I'm pretty sure they're used for controlling air direction with your heater and a/c. The third hose should connect to a vacuum reserve canister that looks like a coffee can on the passenger side of the firewall (down low below the charcoal canister). It provides vacuum as well for heat/ac controls.

    Since we're talking about vacuum lines and with the rough idle, I wonder if you've got the necessary vacuum to your distributor to advance timing?
     
  5. mrmclargehuge7

    mrmclargehuge7 Member

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    downsize_original.jpg


    This is a picture of what it looks like. The middle port goes back to the firewall like his connected port does. Left one goes up to a T that connects into the firewall. Left port makes the car run a lot smoother, especially in idle but when I capped it, the car would die when i started it in idle if I didnt give it gas. Please help, if you have any other ideas!
     
  6. rthomas771

    rthomas771 Member

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    Anytime you fix a vacuum leak you need to adjust the idle. In other words a vacuum leak will cause the engine idle to rise
     
  7. Jeff S

    Jeff S Member

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    I have a '77 250 I6 and that connector I have only has 2 openings, one is open, and another is ran to the transmission

    http://mmb.maverick.to/showthread.php?t=62751

    Great info in this thread, helped me a lot when I was rerouting my vacuum lines
     
    Last edited: Apr 12, 2010
  8. mrmclargehuge7

    mrmclargehuge7 Member

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    I have had it capped for a couple weeks now and adjusted the idle but since ive capped the port my car has a very strong gas smell. Everytime I drive it is strong even with the windows down it remains. Any other suggestions as to where this port needs connected, I dont have the money to let a mechanic work on it. Advice helps a ton and pictures helps even more. Thanks
     
  9. Jeff S

    Jeff S Member

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    Check everything that has to do with the charcoal canister, also, you may want to check all the fuel lines under the hood, you may have one thats cracked and leaking gas but it evaporates before you can detect where its coming from.

    You may also have a bad tube-hose connection and gas is leaking down the tube under the car, which would explain the strong gas smell even with the windows down.
     
    Last edited: Apr 29, 2010
  10. indyman13

    indyman13 Member

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    Do you still have the charcoal canister installed on the car? An open vent line into the engine compartment without a canister will produce strong gas smell and they'll work there way into the passenger compartment.

    The charcoal canister is pictured as well as a simplified vacuum arrangement for the port on the intake manifold.
     
    Last edited: May 5, 2010
  11. Jeff S

    Jeff S Member

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    That second pic is a LOT of help for me, THANK YOU!

    on mine the splitter on the firewall had 3 openings, one was plugged...could a problem arise out of me bypassing the splitter?

    Im not in any way intending to hijack the thread, just wanted to ask this since its here, and could be relevant to the issues at hand in this topic.
     
  12. indyman13

    indyman13 Member

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    The splitter supplies a vacuum source to run different stuff. The one on the right side of the I6 supplies the same level of vacuum to all three holes. You could run a Y-adapter off the splitter on the right side and still have the same level of vacuum you need.

    Take a look at what the original thing looked like and you'll see that there's enough suction there to run a sump pump!


    There are of course other vacuum "sources" under there (a couple of the carburetor I think). On my car, one of the car vacuum lines supplies my distributer's vacuum advance. I don't know if the level of vacuum supplied by those two sources are the same or not.
     
    Last edited: May 5, 2010

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