I have an EP3 2002 my question it's about a strange sound in the intake I have a v2 AEM the thing happens speciality whe the car is cold and shift from 1 to 2 gear or 2 to 3 gear very quickly sound like a explosion not to lound but enough to hear inside the car .
Somebody knows if the sound it normal for uses cai intake or some problem could have the engine?

 

never heard of it.. any chance of a sound clip?

 

ill try

 

does it actually sound like an explosion? like a backfire? is it engine noise or exhaust noise? because a cai will make both louder.

 

Sound comes from the air filter

 

It's called an intake pop. I happens to my ep3 about once a month or less. It's happened to me on the track several times when I'm downshifting from 3rd to 2nd after being on full throttle (people thought I'd blown something). On my car it does it most often with my "winter" SRI, but sometimes with the CAI also. I recall being concerned about it a few years ago when I got my first intake. I seem to recall doing some searching and finding out that it doesn't hurt anything and happens to a lot of people. Anyway, it's not fire, its just air - even though it sounds like a bomb. Do some more searching, I only found a few this time:
https://honda-tech.com/forums/acura-rsx-dc5-honda-civic-ep3-32/02-civic-si-backfire-506142/
And (post 21 - 22) http://www.preludezone.com/4th-gen-h...take-pops.html
http://www.civicforums.com/forums/26...ir-intake.html