High Pitched Whine at Half Throttle

[Tommy VanNess]

Hey All,



I have a high pitched whine that I hear while between 1/4 and 1/2 throttle. It sucks because it is right at the level to maintain a cruising spped on the freeway. I don't know how else to explain it, but it it very high pitched, almost like engine noise from a stereo system. It isn't engine noise because it happens with the radio off. I also tried the cruise control thinking it might be something with the pedal, but the same result occurred. Has anybody had this or know what it is. 01 ST with about 137,000 miles on it. Could it be a vacuum line or something? Thanks for any info.



Tommy

 

[Jacob Dryer]

Almost sounds like a throttle body whistle the way you are discribing it. Did you change anything? Do you have a cold air intake?

 

[Chris Taylor]

Possibly Alternator. There was a TSB on it for a "hoot" noise. Sounds like a high pitched, almost pure tone, maybe like a bearing with not enough grease on it. It went away as the engine warmed up. Started about 1500rpm and lasted to about 2500...



Are the temperatures where you are really cold, or are you in a cold snap? The alternator problem usually occurs below 20 degrees F, but mine did do it at times up to about 30 degrees. Had it replaced under warrenty with a higher output one and no problems since. I think CoastieJoe had the same problem about the same time too...

 

[Scott Tanner]

Tell her to stay home next time... :lol:



(sorry, couldnt resist....)

 

[Frank Marano]

check to see if your air filter is sitting correctly along with the air filter cover......could be an easy fix...wouldnt hurt to check

 

[Tommy VanNess]

:lol: @ STanner



Thanks JDBoxes and fmarano. I do have the MAC intake. I will check when I get home. How would this cause a whine with the throttle body? The temps here are not too cold. Seattle's low temps are around 32. Gets up to 50s during the day. But even when it is warm out, it still whines. Even when parked and I give it a little gas.

 

[Chris Taylor]

Ok, doesn't sound like the alternator problem then if you're not that cold... I'd look to the intake now too...

 

[Tommy VanNess]

Thanks guys for the info. It is a major help just to know where to start looking. Next chance I get, I will take a look at the intake. Gosh I love this site.

 

[Paul H]

If you can't figure out the problem and want to correct the "Throttlebody Whistle" take off the TB and look at it straight on and you will see at the top of the TB is a small opening that goes to the IAC. There is a sharp ridge there, LIGHTLY sand that ridge smooth. Be careful not to take to much off, just enough to round it.



***Make sure after doing this to clean the TB and remove any of the plastic dust that you create.***



Paul H

 

[ReggieMRegalOne05 Legaspi]

Is the front passenger seat occupied?, that's a usual source of whines. j/k

 

[2]

Is the front passenger seat occupied?, that's a usual source of whines. j/k

That symptom appears at full throttle, not half throttle.

 

[Scott Heckler]

I thought it happened as soon as the passenger seat was occupied.

 

[Tommy VanNess]

Thanks Paul H. Great info. I will check it out ASAP. (work and school today, in class now) Is this common? A Throttle body whistle can be heard clearly in the cab?



LOL Regal One '05, Olaf W ScoTt. Sometimes I have heard the whine from the back seat too.