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WHOOSH after shutoff?

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Old 10-21-2007, 11:06 PM
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Default WHOOSH after shutoff?

Just remembered this..I always questioned it. On the 89...whenever I shut it off there was an audible koosh/woosh back through the intake. Air..reversing. What the heck was that all about? The L27 doesn't seem to do it, but the LN3 did it EVERY time.
Old 10-21-2007, 11:08 PM
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i had the same on mine as well, and it was EXTREMELY audible when i had the cai on there
Old 10-22-2007, 06:45 AM
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It'* not normal from the ones I've seen.

Maybe a vacuum leak somewhere?
Old 10-22-2007, 07:42 AM
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Our L36 did it from the day we bought it (with 28,000 miles) to the day we sold it (with 174,000 miles).

Never put any effort into figuring out what caused it.
Old 10-22-2007, 10:03 AM
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Ours did that too on occasion. Would only happen if it failed to start. I always thought the motor was on a compression stroke, but didnt quite fire, so it kicked it back while another cylinder was on an intake stroke, and pushed air back through the intake. maybe i am wrong? :?
Old 10-22-2007, 10:53 AM
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My '89 did the same thing all the time, and sometimes my '93 does it also if I release the key to quickly and it fails to start.
Old 10-22-2007, 01:18 PM
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My 93 did it when I shut it off when it had high idle problems, or it would do that if I didnt start the car long enough and the ignition didnt catch.

I suspected that it was just the momentum giving the crankshaft one last extra stroke after ignition cut off, and the whooshing noise could be the air rushing through a narrowly-opened valve.
Old 10-22-2007, 01:26 PM
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Yeah, I never thought anything was wrong, just always found it interesting. IIRC, it didn't really start getting noticeable until about a year after i got it...and then it just became downright loud If all the series can do it...yet some don't...what the heck is the difference thats making them do it? Because like a said..mine became noticeable, wasn't always there.
Old 10-22-2007, 01:44 PM
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my guess would maybe be differences in airboxes? john, did it get louder once you put a k&n in?


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