What could this be?

[Blackened300a]

I just recently installed the Spaz intake back on my car. It has a very slight tin sound at idle, but its quiet while driving so thats a plus. Since I installed it, I been tuned to hearing for noises and I noticed something today that may be normal or its a issue.
When the engine is running, there is a high pitched whistle at idle. Its not incredibly loud but I can hear it only with the hood open. When I shut the car completely off, the sound continues for a few seconds and then it shuts off and makes a whoosh sound through the intake. Like it released a burst of air in the intake. Any idea what this could be?
It does it each and everytime I start and shut off the engine. I was thinking IAC or some sort of vacume release, but I have no idea at the moment.

Thanks for any info.

[ImpalaSlayer]

mine does the same, im pretty sure its the vacuum accumulator on the drivers side bleeding off

[justbob]

Sure sounds Vacuum related. Idling any higher, even slightly?

[Egon Spengler]

I will be watching this. I have that same hissing

[Blackened300a]

mine does the same, im pretty sure its the vacuum accumulator on the drivers side bleeding off

That sounds logical. Its coming from the driver side.


Sure sounds Vacuum related. Idling any higher, even slightly?

Idle is fine. I been keeping a watchful eye on the idle cause I know that means a leak. When I give it a rev, it drops back down and stays at idle RPM. I been driving the car to work the past 3 days to make sure I don't have any issues.

[SpartaPerformance]

Why didn't you bring it by the shop so I could have a listen? I got a new spray bottle full of soapy water, we can test out for vacuum leaks. :D

[RacerX]

So howz the tank running with the spaz back in otherwise?

[babbage]

So howz the tank running with the spaz back in otherwise?


+2 - I also get the exhale through the intake at key off - that's normal. The whistle could be from the change in shape of the intake, or did you not hear this before.

You are probably being paranoid after listening to a crack through a bad weld.

So, hows the oompf? Any new timeslips in your future?

[FordNut]

Time for some N/A 12's!

[Krytin]

Whistle at idle could be a leak. Test with some starting fluid while running - short burst around area where you hear the whistle - if the rpm increases it is being drawn in by the leak.

[Blackened300a]

Why didn't you bring it by the shop so I could have a listen? I got a new spray bottle full of soapy water, we can test out for vacuum leaks. :D

Yeah except if it has a leak it will suck the soapy water in and do nothing but shoot bubbles out my exhaust.


So howz the tank running with the spaz back in otherwise?
No doubt more power in the mid-high range.


+2 - I also get the exhale through the intake at key off - that's normal. The whistle could be from the change in shape of the intake, or did you not hear this before.

You are probably being paranoid after listening to a crack through a bad weld.

So, hows the oompf? Any new timeslips in your future?

Timeslips will be coming when I get a full exhaust done (sometime soon) and a tune.


Time for some N/A 12's!

Still in the hunt!


Whistle at idle could be a leak. Test with some starting fluid while running - short burst around area where you hear the whistle - if the rpm increases it is being drawn in by the leak.

I tried that already and nothing. Ill give it another shot tonight for good measures.

[SpartaPerformance]

After listening it tonight I think its the short runners on the intake. the car idles smooth as glass and even with playing with vacuum lines, playing with throttle no change.

[NYGarageQueen]

Interesting - I will go out and listen for the same thing to see if it is normal while I have everything apart. I think I might of heard the same thing, but have open manifolds blasting, its hard to hear anything :D

[MENINBLK]

Could be the air suspension releasing pressure.
Whenever I get out of my car and close the door I hear a slight hiss.
When you hear the hiss, put your hand on your rear tire
and lean against the wheel opening.
If you feel the car drop slightly, this is what it is.... :coolman: