so im testing out my new Injen CAI and i hear a very pronounced knocking sound between 1 and 3 thousand rpm upon acceleration and upon releasing the gas as well which i never heared before the install. i have ruled out the CAI vibrating as it was installed perfectly and i have rulled out exhaust leaks (cause it does it when i let off the gas) and have ruled out low oil levels etc as i take very good care of the engine and service it. so whats this pinging knocking noise coming from the engine? it does it very pronounced when im in 2nd gear and get it to about 2 thousand rpm and then when i let of the gas in that range as well for 2 seconds untill it dips below the 1500 rpm range. i cant imagine the air induction causing any type of engine noise but then again it could be something else. this is very troubling. does anyone have this problem? thanks RX

 

sounds like vibration to me, at first i thought detonation, if the maf got knocked around too much during the install and therefore you were running lean, causing detonation. But you said you also hear it when you let off the gas, when would not be detonation at that point. so maybe it bumping into something, can you have someone rev the car for you while you listen in the engine bay.

 

well i thought it was vibration too but i cant tell becuase it only does it at that rpm when rolling and not in neutral when car is stopped. so it still could be vibration and that pitch is not created in neutral. i dont know really know what to think. but when its reved in neutral none of that noise exists. i also shook the CAI a bit and its solid without it touching anything and rubber bushings are in place. so im lost here. any other suggestions? could it be from the engine if it does it upon relesing the gas? thanks RX

 

Something loose around the CAI inlet maybe?
If all else fails, put the OEM intake back on and check for noises.

 

^ word. try having someone rev the motor while you look to see if anything is even noticeable. ??? that sucks. hope you get to the end of this.

 

Sorry to hear about your troubles and I hope you get it all figured out. Off topic: I have the same intake (except mine is the CA setup vs your short ram) do you notice the turbo-like whistling at part throttle? I imagine you would... just curious.

 

Very possible you are rubbing that aluminum AC line. Don't wear a hole in it now.

 

Good point. Be sure to get that AC line covered in the area where it meets the intake tube.

 

yea i checked for loose stuff. i dont get it. the knocking is loud too. and its under the hood. wish i could stick a guy under there and drive man i dont wnat to put the stock back on

 

yes it sounds great. but the knocking sucks!

 

put it back and on check to count out the CAI you put in. i don't understand why you wouldn't attempt this?

 

i will take a look. but i shook the tube around and it touched nothing. i will try it again. thanks RX

 

dont understand why what? why i dont want to put on the OEM back on? becuase it takes time and i know it didnt do it before. i will try and remove it all and reinstall though. thanks RX

 

Yea too bad nobody realized that until my AC line was done LOL... The injen CAI does have a turbo like forced induction sound and whistle and the knocking i have never had, hmm

 

yea its not the ac line. im going to have to take it all off and reinstall. the wierd thing is is that it doesnt do it in nuetral nomatter what the rpms are. its at a certain driving range so it must be a rattle but it really sounds like the motor. damn! ???????