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Thread: Vacuum lines wrong and runs funky

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    Default Vacuum lines wrong and runs funky

    I need help with a 1977 280z. All the vacuum lines on the car where messed up and disconnected when I got it and I can't find a diagram anywhere. I guessed on a few. The car runs great for a minute then like garbage then great then garbage. It's really hard to start when she's cold and the rpm's are at 2000 until it warms up. It's not a CA car and has a 5 speed. Anyone know what the heck is going on

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    Here's a link to the Factory Service Manual (FSM) on the 1977.

    http://www.xenons30.com/files/FSM/77_datsun_280z.zip

    There should be a vacuum line diagram in there in the emissions section.

    Truly the fastest method would be to chase down another 280Z and take pictures, draw diagrams. The FSM is ...obtuse.

    I rather doubt your cold starting problems are related to vacuum lines. More likely your Auxiliary Air Valve isn't functioning properly, and/or your cold start injector isn't squirting. Suggest you SEARCH on AAV here and read up on theory of operation, cleaning/testing replacing.
    Last edited by Wade Nelson; 07-20-2013 at 05:46 PM.

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    Wade, the FSM is among the best I've seen for any car -- well organized, comprehensive, good diagrams. I don't know why you think it's obtuse.

    If half of the vacuum lines are hanging open, that could result in a rather lean condition, but I agree with Wade that your problems are probably greater than just vacuum lines. The 280's engine isn't particularly complicated. I'd recommend just going over it from end to end. Check and verify each part and move to the next. Pay special attention to the electrical connectors. Get them clean, and goop them with a bit of dielectric grease. The most problematic connectors are on the front of the engine on the thermo housing -- thermotime switch and coolant temp sensor.
    My last three sports cars while I still owned all three:

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    Fast -- I agree, it's a GREAT manual --- better than most. But the FSM vacuum line diagrams are virtually IMPOSSIBLE to translate into real world "this hose goes from here to here..."

    As often is the case with manuals, it makes PERFECT sense AFTER you get it all hooked up correctly...

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    Click image for larger version. 

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    Sadly I agree. The FSM as a whole is great, but the diagram for vacuum hose and fuel piping is not the easiest to read.

    Here is a better copy of it that I found on the internet. I'm in the same boat, preparing to rework all the lines - so I just happened to be looking for it last night.
    Kelly R. Johnson
    1978 280Z...yes it's automatic...but I'm fat.

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    That's the same diagram in my FSM for 75. If you're talking about the vacuum lines for the HVAC controls that's a different story, they are usually brittle and somewhat difficult to get placed on the proper ports, and you must constantly refer to the FSM diagram and trace all the lines.
    Last edited by mjr45; 07-23-2013 at 10:36 AM.
    75 280Z almost done
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    Many of the hoses came from the factory labeled with a letter on a small piece of tape. If you're lucky the piece of tape is still there. If you change a hose, move the label or put a new one on. The letters correspond to the diagram.
    1976 280Z, with some minor modifications

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    I need help with my 280zx 81 (2+2) model it was a turbo but the turbo got taken out by previas owner.
    The vaccume lines are all messed up any help
    SHUTS OFF UNTILL WORMED UP VACCUME ISSUE!!!

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    Quote Originally Posted by Alexyu View Post
    I need help with my 280zx 81 (2+2) model it was a turbo but the turbo got taken out by previas owner.
    The vaccume lines are all messed up any help
    SHUTS OFF UNTILL WORMED UP VACCUME ISSUE!!!
    You should start your own thread and put a little more work in to describing the problem. Can't tell what the question is. The caps and exclamation points don't really add anything.
    1976 280Z, with some minor modifications

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    1978 280Z (stock) TomoHawk's Avatar
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    Ditto on putting the labels on the ventilation hoses. You might also make notes on the size and how long each is for the next time.
    Drive Responsibly.
    enjoy classic Rock music.

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