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Trailblazer Vacuum llines

Discussion in 'General Chevy & GM Tech Questions' started by musicman21061, Apr 7, 2009.

  1. musicman21061

    musicman21061 New Member

    I'm customizing my trailblazer. One thing i'm doing is putting in aftermartket guages one of which is vacuum guage but i have no idea where any of my vacuum lines are. Can anyone help me?
  2. bry2500

    bry2500 Epic Member 5+ Years 1000 Posts

    Welcome to the site!!!!

    On the fan shroud or front frame near the hood latch should be a label with the vacuum line diagram. I have only one accessible vacuum line on my 8.1L and it is 1/8in diameter. I hope you don't have the same problem.
  3. Z71_guy

    Z71_guy Epic Member 5+ Years 1000 Posts

    welcome to the site
  4. bob13

    bob13 Epic Member 5+ Years 1000 Posts

    Welcome to the site! You could use a Chilton Manual or another repair book to give you that information. Maybe even online.
  5. adampaul1964

    adampaul1964 Epic Member 5+ Years ROTM Winner 1000 Posts

    Welcome to the site!
  6. dwill3015

    dwill3015 Epic Member 5+ Years ROTM Winner 1000 Posts

    Welcome to the site!
  7. MrShorty

    MrShorty Epic Member Staff Member 5+ Years 1000 Posts

    Moved to general tech

    You might post your year/engine, in case it makes a difference in vacuum supply.
  8. KirkW

    KirkW Rockstar

    You can install a "T" fitting in an existing vacuum line easily enough. The harder part will be determining which lines are 'constant' vs 'ported' vacuum. Constant vacuum sources always see a vacuum. 'Ported' vacuum is only present at certain throttle settings (typically no vacuum at idle, but normal vacuum above idle throttle opening).

    Typically, any vacuum line that terminates directly into the intake manifold is a constant vacuum source. Examples would be the fat hoses that lead to the power-brake booster, PCV valve, or a choke-pull-off on older carbureted trucks.

    Any lines that terminate in the throttle-body can be either ported or constant. Absent the factory manuals, the only way to know for sure is to connect a temporary vacuum gauge and see if it registers full vacuum at idle - generally that indicates a constant-vacuum source.
  9. leadpan101

    leadpan101 Rockstar

    i am actually a friend of the guy who posted this, and we figured it out thanks for the help?

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