Help just bought an evo, and the car when decellerating makes a bird chirping noise.
 

Hey. So i bought the EVO IX up in NC, and just got back last night. The drive was pretty smooth, as I was cruising pretty much the whole way home on the highway. I babied the car all the way home, and when I turn onto the loop into my city I noticed when I was slowing down the car, I hear this weird high pitched noise that really sounds exactly like a bird chirping, and its not consistent - its like a bird song, high squeek, pause, squeek, squeek. I honestly stopped the car and thought a bird was chirping every time I slowed down to try to pin point the sucker. It really only seems to happen when I slow down and from what I can tell it doesn't matter whether I am in gear or not. I thought maybe the noise was due to the long drive so I parked it last night. Upon starting the car up this morning and driving I started to hear the noise as I slowed down at my 3rd stop.

Mods:
HKS Type RS Blow off valve (i think)
DC Cat Back exhaust
Glowshift gauges

I am really worried because all I hear about is the infamous death whine. Does the death whine sound like a bird chirping? The car seems to be driving incredibly well under acceleration, and the noise from what I can tell so far is not there under accel. I have listened to the youtube videos online and it doesn't sound similar. Also the car was not making the sound on the trip back, I did not hear it when stopping for gas/food. It really sounds like a damn bird chirping, like someone is playing a big joke on me with some sound device under my car.

I have read about this on a few threads but I don't think anyone of them ever concluded with a solution. I have read alot of stuff pointing to blow off valve leak, but how would I go about checking that. Wouldn't it seem if that I accelerate (not boosting) and then decelerate and no sound is produced, then accelerate (boosting) and then decelerate and sound is produced- that it may be blow off valve leak.

I'm super happy about joining the community, but want to make sure that my car is "healthy."

This is the death whine. It's constant, even on accel and decel.
http://www.youtube.com/watch?v=TXbisxnAW-s

Could just be a warped rotor and/or brake pads breaking in.

Yeah I saw that video, and it doesn't sounds like that. The transmission is operating very smoothly and seems to be transmitting power fine - maybe I'm having death whine paranoia. It chirps and currently am only hearing it when decelerating. After my day today I will put up a video to help better diagnose this.

Check the brake pads..could be the squealer touching

My bov used to make similar noises on deceleration. I notice you have the HKS, mine was a Greddy but still something you could look at. Maybe adjust the spring and see if the noise continues.

Mine made a noise like a bird chirping on decel when I had a boost leak... I forgot to tighten up one of the clamps on the UICP after some maintence and when I hit boost it popped loose and would make a sound similar to what you're describing.

Belts? Small rock in brake?

im going to lean toward check your breaks mine did the same, also check all the intercooler clamps, and check your blow off valve vac lines.

Im also going to say its the brakes. Evo's are notorious for having noisy brakes. I have that same t-case noise in my IX MR been like that for 3 years.. lol

Eeeek sorry. Its a Greddy not an HKS, I was thinking Greddy while typing HKS. I'm not really positive on the model, but it is a Greddy sorry, I tried looking at some images online to identify it but later tonight I will look more specifically.

So your saying I might need to adjust the BOV. Any instruction would be greatly appreciated.

Do I need to disassemble the brakes to check for a brake related issue? I am literally a two day old Evo IX noob but have experience working on cars.

Those valves are some of the most annoying sounding valves on the market, next to the HKS SSQV and my best guess as to why the previous owner even installed it was for that stupid sound alone. IMO, get your hands on a new or used factory IX BPV and install it.

Suddenly....no more birds under your hood!

lol agreed on the hks ssq...I had them on the Z and changed the insert--they always sounded like Star Wars guns to me. Anywho, I went back to recircs and traded the ssqs for eibach springs and a lightened driveshaft.

I like the sound, but the bird noise drives me up the wall. I am assuming that a tune would be recommended if I decide to change the BOV? I plan on taking the car to a shop and having the car re-tuned, as the dealership/shop I purchased it from tuned it in North Carolina. Is the change in weather (humidity/temperature) different enough for a tune to make a difference in terms of reliability (idle, accel, decel, boost)?

Update: Didn't get any video of the noise - late getting home. I did test the noise, apparently the noise occurs as I let off throttle at boost below 0 psi (the vacuum side of the boost gauge). I am kind of starting to lean towards a vacuum line. Tomorrow I have a pretty free day so I think I'll pop the hood and check out all the vacuum lines. Assuming it doesn't rain like today.

Thanks for all the input.

BOV dude, most likely when reseating.

LOL, definitely the Greddy, my mechanic, with his delicate sensibilities, prefers to describe it as a small fart, instead of the "bird Chirping".