Shut hood when car is running and the car's idle drops...
 

It's probably just one of those weird EVO traits but I have never had a car do this to me. So today I was just looking over the motor and when I went to shut my hood as soon as the hood shut the car's idle dropped like it was going to stall and it came right back up within a second. I was like WTF, so I opened the hood and then shut it again. And again the idle dropped and came right back up.

I call my buddy with an 05 Evo 8 and he said that sometimes his does the same thing.

Is this normal? And why would the air flow change when I shut the hood and almost cause the car to stall?

It's not air flow - it's the knock sensor. The vibration created by the hood closing sets off the knock sensor, which thinks it just detected detonation and is now going to pull something to protect the engine from self destructing. It's like Evo kryptonite. I've been lined up behind some big American V8 at an autocross and when the V8 roars my idle goes to hell in a hand basket. I've read other guys posting on here saying the same thing can happen when drag racing.

Cool thanks. So there is nothing to worry about then. At first I was like 250 miles and I might have to take my car back to the dealership for warranty work. Thanks for the fast response.

Its as if the knock sensor makes our cars scared of little vibrations, so I guess our car shakes when next to a loud v8!!

No problem - just don't try to race a Kia with a killer subwoofer who knows how to use it. ;)

that sucks dont let anyone rev too hard next to u like an srt-4 with dump exhaust

Thanks again everyone.

dont slam your hood either, place it on the latch, then just lightly press it shut with your hand.

people get out of my girls car....her included and slam the **** out of the doors :updown:

Weird I wouldn't have imagined the knock sensor being that responsive. I'm not sure if thats really a good thing or bad. Does this mean when adding say a TBE with a test pipe there is an increase in the cars vibrations, then that would affect the amount of knock your knock sensor sees?

With the number of people running that setup on here, I doubt it's a problem. Otherwise, you would hear more about it. You can probably do some searches for 'knock sensor' and find some earlier discussions of this issue (but I'm the first one to agree that searches are about useless anymore on here). From what I remember, it was mostly people noticing their idle degrading when near low rumbling exhausts, and various hood slams.

It is just one of those things that we have to deal with, it should be a problem though, at least you know your knock sensor works!!