by Chinky420 » Fri Sep 26, 2008 8:37 am
yeah, if it's like...more of an electric whistle/buzz then it's interference with your electrical and your headunit....i used to have that when i had my factory HU, but upgraded with subs....the elec components they had to install for the sub output was giving off some interference with the head unit....meaning i would hear that slight whistle/buzzing all the way up the powerband, and only when the sub's/speakers were low enough to not hear the music. check out what aotoyota said...
now if you're talking about it coming from under the hood, then it probably is a vaccuum leak. but typically, if it is associated with the intake system, then it will usually only show symptoms (make the whistle) at certain RPM's, or at certain positions of th throttle plate (i.e. like the whistle i get with my throttle body spacer......when i'm at WOT i don't get it, and when i'm at <60% throttle i don't hear it..but if i'm accellerating at 60-85% throttle, i get a neat whistle sound).
and it doesn't sound like anything from your exhaust.....an exhaust leak sounds way different than what you're describing.
given all the information you and everyone posted above, i'd troubleshoot as follows:
pull out the head unit, inspect the wiring, inspect where power wires are in relation to speaker wires (if they have to be near each other, then you want them crossing at a 90 degree angle, rather than running alongside each other), inspect the HU ground wiring, and make sure everything is tucked away nicely.
if you still have the exact same sound (i.e. fiddling with the HU didn't change the tone of the whistle at all), then you may want to go on to consider the intake system....however, if you're running a stock intake, the only thing(s) you're really going ot have to check is the vaccuum lines. also, follow lovemylara's advice on the starter spray to indicate whether it IS a vacuum leak.
oh yeah, you can also try turning off the headunit completely (either by detaching the faceplate, or if there's an off button then hit that)...and that should make the buzzing/whistle go away (i.e. only if you can hear that there is no longer a signal going to the speakers....so basically, you can no longer hear the white noise behind a silent speaker). this should tell you whether it is electrical or vacuum.
GL and i hope this helps.
