I saw this somewhere on the board, but the search wasn't working so I just thought to post and ask. I just installed the FIPK and it is working great, but for the first couple minutes it makes a hissing noise, which then goes away. Is this normal, or will it just stop eventually once the computer learns it.

The install was super easy, around 45 minutes and that is coming from someone is not very knowledgable. I am learning every time I make a mod, but I love doing it. If only I had unlimited money to make the mod.

I did however, drop a clamp down and it got stuck, adn the only way to get to it was taking the fan belt off, and that is where I had my trouble, it was the last thing I had to do too, and I would of been finish but my stupid self knocked it down and it fell right into the perfect crack.

 

There are some threads on this topic. That sound is normal and you can expect to hear it with your FIPK. Just open it up to WOT and it will go away!

 

Is yours the 4.6 or 5.4? The K&M instructions have a tip for the 4.6 if you hear a whirring noise... involves cutting a part off of one of the tips or something.

 

its the air bypass valve (black box above the pcv connection). if you took that out and used the bypass hose provided in the kit you may want to consider putting it back in.

i heard that same noise, put the bypass back and its been perfect since. its sort of an odd fit, but it worked out fine.

i believe that this is specific to the 4.6 only.


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mr k
_ ____________________ _
1999 f150 xlt ex-cab 4x4
4.6 triton v8
5 speed manual
3:55 rear
towing package
k&n f.i.p.k.
gibson ss swept side

 

I have the 5.4L. I called K&N and they said it was normal and it would stop in a couple days. It may of had to do with the unusual cold out here. Once the engine warms up it stops. I kept the black box on after the install so I don't think that would be the reason. Hopefully time will fix this, if not I will be calling K&N again.