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When i start my 90z sometimes it makes a gurglin sound on my drivers side, so i took my wheel liner off and noticed the filter box and a valve connected to it, so i took it apart and noticed that the filter was wet, i went ahead and blew the water out and let it dry, put it back in and all fine. wonderin if thats normal or is there somethin wrong? thanks
 

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That's called the AIV system - it's part of the pollution control system and gurgling from water inside is a common issue. You did the right thing -- might want to check out the other side of the car too. There's another one over there...


FYI - These valves introduce some air into the exhaust stream to help reduce emissions (believe I have this explanation right?)...
 

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Yes, jzack, when the AIV solenoid is engaged the exhaust can draw fresh air thru a check valve, which cycles with the pulsing of the exhaust pressure, blocking reverse flow and letting air thru when the pulse goes negative or a negative reflection wave occurs.
 

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Don't know why the AIV's collect water, but chances are they will fill with water again. The solution is to drill little holes in the bottom. Here is a write up http://twinturbo.net/nissan/300zx/tech/aiv/aiv.html
When the reed valves get clogged they do not close. Exhaust then flows back up and into the wheel wells. At stop lights the exhuast gets sucked into the cabin. That is the reason why I rebuilt mine.

Many people delete their AIV's. But if you have a stock ECU the programing dumps a little bit of extra fuel so that at the cat, the fuel and extra air will mix and burn. This keeps the cats nice and hot ready to burn up any bad stuff at take off. No AIV and stock ECU equals rich at idle. Most aftermarket tunes delete this function.
 

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I think they collect water from atmospheric humidity - over time it just builds up...
 
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