Hissing Under Moderate Acceleration
Joined: Nov 2006
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RE: Hissing Under Moderate Acceleration
ORIGINAL: dsertdog56
Hissing under acceleration...probably a misalignment between your air filter box and T/B, or your air box to T/B gasket is missing.
If you have a K&N, try lifting up on the tube down by the filter. If you see a gap between the T/B and the tube, thats your hiss. It doesn't take much motor flex under acceleration to do this.
Hissing under acceleration...probably a misalignment between your air filter box and T/B, or your air box to T/B gasket is missing.
If you have a K&N, try lifting up on the tube down by the filter. If you see a gap between the T/B and the tube, thats your hiss. It doesn't take much motor flex under acceleration to do this.
Record Breaker
Joined: Jul 2006
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From: Warren, NJ
RE: Hissing Under Moderate Acceleration
ORIGINAL: nitrospaz19
My truck is usually like a quart low when I go to change the oil
My truck is usually like a quart low when I go to change the oil
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RE: Hissing Under Moderate Acceleration
AAA4948 - I notice the same thing with my truck. Basically the same description you gave in the first post.It usually happens when going up a slight hill. I'm pretty sure it's just the noise of the air moving through the throttle body. Check for air leaks between the air filter housing and the throttle body as described.
With my truck, it is more pronounced since I have a 14" round air filter. It was very noticable when I had the 2" high filter on, but got quiter when I moved up to the 3" high filter. I wonder if it isn't the Idle Air Control (IAC) opening up slightly under the load. When you step harder on the throttle, the IAC closes again since your butterflies are open more in the TB. That's just a guess, but I'm basing it on the noise being similar to the soundthe truck makes when it is idling after I first start it up. Bascially, its just the sound created when air is moving quickly through a small opening, just like having a window open a crack when the wind is blowing hard.
With my truck, it is more pronounced since I have a 14" round air filter. It was very noticable when I had the 2" high filter on, but got quiter when I moved up to the 3" high filter. I wonder if it isn't the Idle Air Control (IAC) opening up slightly under the load. When you step harder on the throttle, the IAC closes again since your butterflies are open more in the TB. That's just a guess, but I'm basing it on the noise being similar to the soundthe truck makes when it is idling after I first start it up. Bascially, its just the sound created when air is moving quickly through a small opening, just like having a window open a crack when the wind is blowing hard.
Thread Starter
Joined: Apr 2007
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RE: Hissing Under Moderate Acceleration
Thanks everyone. I think this is just TB air noise. My friend and I drove around the block in his truck with the air filter off once just to see if there was a difference. Same noise now that I know what I am listening for. Guess I got lucky with no problems again.
