What is this noise!!!! Help

J

Justin89SC

Registered User
last weekend the car started this noise. Its only when the car is pulling 18 to 20 psi. I thought it was the bypass vavle, i replaced it with another one, and still makes the noise.

The car did make a 800 mile round trip this weekend and managed the do 14.8 @ 93 mph making this noise.

Any help would be great!!

 
sounds kinda like a jet lol, i bet other people as you go buy are tripping. dose it get louder as you apply the pedal, or dose it just stay at that sound level?
 
noise

when you get engine noise and can't figure out where it's coming from: find 1-2 ft. steel rod, 1/2- 1" thick, with engine running put one end to your ear, other end to different areas of engine, loudest area will be place to look. You got a loud one there though, earplugs might help.
 
THANKS,

Sorry, yeah, i meant 20 to 18 inches of vacuum. The sound goes away at about 10 inches of vacuum.

I did take the IAC off and spray it down with carb cleaner, but no luck, ill try to get another good one somehow and see. Ill try to unplug the IAC tomorrow

Thanks again!!
 
idle air control. Or a leak somewhere else. You can just spray some fluid on the IAC while the car is running to see if the tone changes.
 
Put a piece of wood or something on the idler pulleys applying pressure while its spinning to see if the tone changes. I had a bearing going bad and it squealed like that also.
 
I unplugged the IAC and the TPS, both sensors at the TB and nothing happened.

Ill check about the belt tensinor this weekend.

Thanks for the help
 
That sounds more like a bad bearing somewhere....the IAC is more of a honk...u have a whine....I would say check your idler pulleys or the SC snout....let us know what happens
 
Ok, what i have done so far...

I know its not the supercharger, i removed the belt and the noise is still there

I unplugged the IAC and TPS sensor, no difference. I plan on still replaceing both with good working ones next weekend.

As for the noise, like i said, the noise is only when the car pulls 20 to 10 inches of vacuum. As soon, as you get at 10 inches of vacuum and all the way into boost, the noise is 100% gone, I still think its the IAC, but dont know.

If it was a tensior, wouldnt the sound get louder or stay the same?
 
Justin89SC said:
Ok, what i have done so far...

I know its not the supercharger, i removed the belt and the noise is still there

I unplugged the IAC and TPS sensor, no difference. I plan on still replaceing both with good working ones next weekend.

As for the noise, like i said, the noise is only when the car pulls 20 to 10 inches of vacuum. As soon, as you get at 10 inches of vacuum and all the way into boost, the noise is 100% gone, I still think its the IAC, but dont know.

If it was a tensior, wouldnt the sound get louder or stay the same?
Click to expand...

you never know things can just happen:rolleyes: pulling the belts are free i would do that first! :eek:
 
Justin89SC said:
As for the noise, like i said, the noise is only when the car pulls 20 to 10 inches of vacuum. As soon, as you get at 10 inches of vacuum and all the way into boost, the noise is 100% gone, I still think its the IAC, but dont know.

If it was a tensior, wouldnt the sound get louder or stay the same?
Click to expand...

Pull the jackshaft belt as well. If the noise is still there it's in the P/s Pump, the Alternator, the Water pump, the a/c compressor, or the tensioner pulley.

You could then pull the main belt (tie it up out of the way, since it's around the lower radiator hose) and start the car and see if the noise is gone completely. The car will run without the belt for a few seconds without overheating.
 
Justin89SC said:
Well, i just removed all the belts, car runs and still makes the noise.
Click to expand...

I still think it's the IAC valve. Remove the air pipe between the MAF and TB and start the motor and see if it sounds like the noise is coming from inside the throttle body. If it does sound like the source of the noise, while the motor is running, hold your finger over the air inlet hole for the IAC valve. It's inside the throttle body on the same side as the IAC valve. Motor will likely try to stall, but you should be able to tell if that's what is making the noise.

David
 
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