THIS TROOPER 2 MONTHS AGO STARTED A PITCHED ...

  • Tiny
  • htc
  • 2001 Isuzu Trooper
  • 160,000 miles

This Trooper 2 months ago started a hi pitched squeal in the eng compt. Sounds like vacuum/intake leak. Have checked every vacuumline all intake gaskets finally found if I manually change the pos of the butterfly the squeal stops. Always squeals at idle. If I move the butterfly and it goes into limp mode, Higher idle and reduced power on dash and no squeal. I have cleaned the t-body and replaced base gasket with no change. Butterfly has no rough edges or worn edges that I can see or feel. When driving only squeals at idle. Any thoughts?

Wednesday, December 26th, 2012 AT 1:17 PM

3 Answers

  • Tiny
  • KHLow2008
  • Expert
  • 41,938 posts

Are you using cold air intake?
If not, check the air hose for leaking. Any vacuum noise from throttle body should be dampened by the intake system.

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Wednesday, December 26th, 2012 AT 2:09 PM
  • Tiny
  • htc
  • Member

No cold air, just stock intake and air box. I wondered about the tube and a possible pinhole. I'll check it real close. I've moved the hose around while running and it made no difference. I even unhooked the air box and it made no difference. This squeal is ear piercing. I don't understand the butterfly position affecting it.

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Wednesday, December 26th, 2012 AT 5:02 PM
  • Tiny
  • KHLow2008
  • Expert
  • 41,938 posts

When vacuum is present and causing a wheezing noise, increasing or decreasing the throttle would change the amount of vacuum and this can reduce or eliminate the noise.

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Thursday, December 27th, 2012 AT 2:29 PM

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