Results 1 to 12 of 12

finding a vacuum leak

This is a discussion on finding a vacuum leak within the External Engine forums, part of the LSx Technical Help Section category; OK so Ive got a gremlin Ive been chasing since february, I've posted about this before, but the hunt continues. ...

  1. #1
    James Bond Spikito's Avatar
    Join Date
    Aug 2007
    Location
    Texas
    Age
    30
    Posts
    4,546

    2001 3.8 Black - sold
    2000 SS Black M6

    finding a vacuum leak

    OK so Ive got a gremlin Ive been chasing since february, I've posted about this before, but the hunt continues.

    Well I've had a breakthrough, and hopefully a good one.

    Backstory: Vacuum leak after header install, its a high pitch whistling inside the cab, that increases and decreases in volume in direct relation with RPMs....i hit the gas, whistle goes up, i let off, whistle gets quieter. Ive tried hunting around by ear, doesn't help, ive gone over everything with carb cleaner, no result. The first suspect was the AIR solenoid, but all that checked out.

    The whistling also starts and stops at random, sometimes its there on start up, some times not, but very often, it starts and stops when I hit a bump, even very small ones.

    So the other day I was at a red light....whistling like hell, I adjusted my A/C fan speed, and the whistling cut off, instantly. So now the last few days, when it starts, i just play with the knobs and it works pretty often, seems like its the two outside knobs that affect it, fan speed, and turning A/C on and off, heat/cold adjustments have no affect.

    I forgot those controls run off of vacuum lines.....any suggestions?

  2. #2
    Super Moderator
    pajeff02's Avatar
    Join Date
    Feb 2009
    Location
    Mansfield, PA
    Posts
    21,567

    Black & Blue
    '02 WS.6 / '07 Suburban

    Do all the controls function correctly? Any chance it is an electrical whine rather than a vacuum whistle?

  3. #3
    James Bond Spikito's Avatar
    Join Date
    Aug 2007
    Location
    Texas
    Age
    30
    Posts
    4,546

    2001 3.8 Black - sold
    2000 SS Black M6

    i dont guess i know what an electrical whine is, unless you mean the sound of an electric motor, but no, its not that.

    im pretty sure its a vacuum whistle, but yeah the controls seem to work properly. I do remember a distinct "Pshh" sound when i changed functions, like i mini blow of valve, lol...but it doesnt do that anymore
    Last edited by Spikito; 08-10-2011 at 08:15 AM.

  4. #4
    James Bond Spikito's Avatar
    Join Date
    Aug 2007
    Location
    Texas
    Age
    30
    Posts
    4,546

    2001 3.8 Black - sold
    2000 SS Black M6

    but like i said, its volume also volumes RPMs exactly

  5. #5
    Spaz is My Mentor SMWS6TA's Avatar
    Join Date
    Feb 2009
    Location
    Ugy Lower Corner of AL
    Posts
    10,509

    Navy Blue Metallic
    98 T/A w/a little mods...

    check the HVAC line. It could have come off the back of your intake or have a crack in the line. This will effect your A/C and cause a vacuum leak and could make a whistling sound as the pressure increases or decreases.

  6. #6
    James Bond Spikito's Avatar
    Join Date
    Aug 2007
    Location
    Texas
    Age
    30
    Posts
    4,546

    2001 3.8 Black - sold
    2000 SS Black M6

    back of the intake....ofcourse....

  7. #7
    Spaz is My Mentor SMWS6TA's Avatar
    Join Date
    Feb 2009
    Location
    Ugy Lower Corner of AL
    Posts
    10,509

    Navy Blue Metallic
    98 T/A w/a little mods...

    did you find it? It attaches to the MAP sensor.

  8. #8
    James Bond Spikito's Avatar
    Join Date
    Aug 2007
    Location
    Texas
    Age
    30
    Posts
    4,546

    2001 3.8 Black - sold
    2000 SS Black M6

    its 107 outside....my ass is on the couch, lol

  9. #9
    Spaz is My Mentor SMWS6TA's Avatar
    Join Date
    Feb 2009
    Location
    Ugy Lower Corner of AL
    Posts
    10,509

    Navy Blue Metallic
    98 T/A w/a little mods...

    baby.....



  10. #10
    James Bond Spikito's Avatar
    Join Date
    Aug 2007
    Location
    Texas
    Age
    30
    Posts
    4,546

    2001 3.8 Black - sold
    2000 SS Black M6

    shut it, lol...i sprayed some carb cleaner back there the other day, no rev...but the leak is also intermittent.

    can i pull the knob cluster out and check for a leak back there?

  11. #11
    Super Moderator
    pajeff02's Avatar
    Join Date
    Feb 2009
    Location
    Mansfield, PA
    Posts
    21,567

    Black & Blue
    '02 WS.6 / '07 Suburban

    On our T/A, there is a vacuum pot for the HVAC that is accessible after removing the panel below the steering column (4 screws) and the panel over the pedals (2 pins). Look above the gas pedal and you will see vacuum lines and such in that area.

  12. #12
    James Bond Spikito's Avatar
    Join Date
    Aug 2007
    Location
    Texas
    Age
    30
    Posts
    4,546

    2001 3.8 Black - sold
    2000 SS Black M6

    most of the time it sounds like its coming from behind my guage cluster...ill check that out sometime

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Similar Threads

  1. Vacuum leak
    By 00hawk109 in forum General Help
    Replies: 6
    Last Post: 07-17-2011, 10:39 AM
  2. Vacuum Leak from EGR
    By jpn8801 in forum General Help
    Replies: 0
    Last Post: 04-21-2011, 06:59 PM
  3. Vacuum leak or not?
    By soop in forum General Help
    Replies: 8
    Last Post: 02-08-2011, 12:56 AM
  4. Possible vacuum leak?
    By shaggsm3ls1 in forum General Help
    Replies: 11
    Last Post: 10-06-2009, 12:14 PM
  5. Help: Vacuum leak (I think)
    By clow76 in forum General Help
    Replies: 7
    Last Post: 08-12-2009, 04:21 PM

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •