hissing noise at engine shut off!
Thread Starter
Staging Lane
Joined: Aug 2007
Posts: 50
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hissing noise at engine shut off! I have a 2000 Trans Am with Headers and X Rumbler exhaust. I disconnected the EGR valve from the headers and plugged the hole in the intake manifold. The other day I started to notice that when I shut the engine off I hear a hissing noise, fairly loud, and Im not sure what it is. I dont remember it happening before but maybe it has always been there. Anyone have any ideas?
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X2, My car done the same thing after my header install. The hoses you took off going to the manifold run down to the A.I.R pump in the front driver side fender. I recirculates air back into your exhaust system, so unless you pull the fuse or take the pump out it will continue to blow air out of the hoses.
Yea so how does it make a hissing sound from the lid with the engine off?
I said it's coming from the AC because it can take over a minute for the pressures to equalize in the system, it will do it over a minute with the engine off. And thats normal.
I said it's coming from the AC because it can take over a minute for the pressures to equalize in the system, it will do it over a minute with the engine off. And thats normal.
It's probably the lid, unless it lasts longer than a couple seconds. At idle, your intake manifold and lid are under a vacuum, when you shut it off, the air rushes in. Mine does it too, at a cold/high idle, you can hear the hissing just from the air going into the lid.
My previous car had one of those cone type K&N filters and it was crazy loud, I guess because the pipe to the intake manifold from the cone was like 3 feet long, lol. Damn fwd cars.
My previous car had one of those cone type K&N filters and it was crazy loud, I guess because the pipe to the intake manifold from the cone was like 3 feet long, lol. Damn fwd cars.
It is not the AIR pump. the airpump only runs for like 15 seconds at initial startup. It will not come on anymore while driving. if hes hearing this when turning the car off, either he has a vaccum leak somewhere, or its A/C related.
