A hissing sound when giving it gas...

[upshiftN]

Ok so about a week ago i started noticing that when i give my 97 GST some power by pushing down the gas, it makes a really really phaint hissing sound. Sounds like something that a lose washer would make on a bolt when spinning freely. But i dunno what it could be... A friend of mine assumed it was some vacuum problem, or leak somewhere, because it's starting to do it more often, and you have to listen closely to hear it. Anyone know what this could be, or starting to be?

 

[GinNBoost]

Sounds like it could be a boost leak. I noticed that you have a Greddy Type S BOV. I have one too and when I go WOT it makes a "hissing" sound, almost like air is escaping from somewhere. Suggestion: tighten the screw a bit or do a boostleak test.

 

[upshiftN]

ok that could be true, and i intend on checking that out... but i don't think that is the problem however. This sound is like the phaintest sound you can hear when driving. You can't be listening to the radio or anything, focusing on the sound really carefully. It sounds like a lose washer on a bolt that's spinning freely, and it's been picking up a lot more recently. Anyone ever experienced this problem before please help me out. Thanks

 

[upshiftN]

oh yeah, i forgot to mention this happens whenever i just give it gas, not necesarily WOT. In fact i don't think i even hear it at WOT. Mainly just when i first get into the next gear and giving it some gas.

 

[x camaro owner]

i hear that noise to on my car. its not a boost leak noise its definitely something else it will be a while before i figure it out. probably some time this summer i will give it a shot

 

[upshiftN]

aight yeah thanks alot man. I definately hear ya on waiting cause it's hard to tell now. Hope to catch up with you later with this.

 

[upshiftN]

ok, i know it's only been a couple days since i last posted about this problem, but today i noticed that it was getting worse. The sound that i'm trying to describe sounds like a washer spinning freely on a bolt that may be lose. I'm not saying that i have a bolt lose or anything like that. I'm just saying the sound i hear when i give it gas sounds like the washer around a bolt sound.. when spinning freely... a very faint sound, that you need to listen closely too, but when you finally hear it, like i did, i hear it everytime now, and it pisses the hell outta me. Anyone think they know what this is? Cause i dont really wanna have someone go through my entire engine to find out what it is.

 

[upshiftN]

anyone out there that might know what this is leading to... please please help me out!!.. c'mon... don't be shy! speak up!

 

[babell2]

If you can hear it from inside the car. Pop the hood, grab the throtle and start looking. With the info in this thread it could be anything. Does the sound come from the floor, engine, tailpipe, trunk?? Give a clue.....

 

[slowAWDTSi]

A list of possible causes:
Trans oil low
Breaks rubbing somethign they shouldnt be
a heat sheild coming loose like on the exhaust system
an exaust hanger coming loose
a wheel falling off
a harmonic dampner coming loose (not likely)
failing throw out bearing (not likely either)
wheel bearing going out
loose heatsheild on the manifold
turbo getting worn out and making noise
turbo getting worn out and getting out of balance(both highly unlikely)
you bought a mitsubishi and mitsubishis fall apart(highly likely)
Its a screw in your head loose
Its the loose nut behind the wheel.
ok the last few might have been pointless but....
With all the info you have given its very hard to say
but check all those then report back
Dru

 

[WoohDSM]

Lol. Or you can freak out just like my dad did when I first gave him a ride. He thought that something was wrong with the car when he heard the turbo spooling up. It is also a hissing sound.

 

[upshiftN]

ok haha.. yeah i did sorta forget to say where i thought the sound was coming from. But yeah, so i hear it even more now, it's still very faint, but most people hear it, happens around 1800-2000 rpms only.. and it's coming from either the gearbox area... or in the engine bay, it's pretty hard to tell actually. But it only happens when i'm giving it gas...I don't know if it has anything to do with the turbo, but i'm gonna tighten the screw a little on my BOV, jsut to be sure it's not leaking at all. It literally sounds like somethings lose... but since it's sooo faint, it's even hard to say even something like that. But definately from either the transmission, the gear box, or somewhere close to the front seats in the engine.

 

[eclipse90gsxt]

So its only when your moving, since you are giving it gas.

Is it like a hissing sound like air through a hose? I had my car do this, and it was the brake dust shield rubbing my rotor, but it should happen all the time when moving.

Does the car drive normal?..meaning can you boost?, if its a huge vaccum leak the car would run like crap or not even idle, or run at all.

If it is a rattling type sound, it might be a rod bearing moving around in the engine, but again that would be constent all the time not just at the rpms given.


So narrow it down, is it like a hissing(as air through a hose leak) or a hissing as metal rubing against eachother?

It might be just something loose. IDK what would happen only in those rpm's you gave though.

 

[upshiftN]

aaahhhhh.. this is sooo annoying. Yeah i mean, it only happens around those rpm's seriously! The sound doesn't sound like a hissing sound like air leaks or something, but i mean it's soooo high pitched that you can't tell what it is... and sooo quiet, most people who come in the car don't notice it at all unless you tell them to listen for it. I mean the best i can describe this is, a washer on a bolt that's lose around it and spinning freely, but it's sooooo quiet. I just tightened my BOV screw so we'll see in a little if that helped it, and it's not a rattling sound at all. And might i add that it doesn't make the sound when in neutral, only in gear mainly in gears 1/2/3. And yes the car does drive normally. I can boost. Nothing has changed at all. I mean my best guess is maybe something loose. How would i go about doing some tests to figure this one out???!?!?

 

[eclipse90gsxt]

It might be something with the trans if it only happens when in gear. Meaning something inside, I believe there is only bolt in there and its for the reverse, arm.

Other than that It only happen when moving because the car doesn't shake or move in neutral. I would start going around the area you think its from and see whats tight ot not.

Like what was mentioned, I would check the Trans oil.

 

[upshiftN]

How do i check for low transmission oil? Where's that located? Or transmission fluid... is that the same?

 

[eclipse90gsxt]

Tranny fuild and oil is the same.

On the front of the transmission there is a 14mm or 17mm plug(I forgot which size), and when you undo that the fuild inside should be level with that point in the tranny. You can put a finger in there and check.

If all fails, just empty the trans by a another plug that is on the front right side, 24mm I think, and let all the fuild drain out, then use the other plug and put in new oil to that fill plug line.

www.vfaq.com might have a faq about tranny oil.

*The mm and locations may be different for a 2G idk, I only own 1G's*

 

[realhp=turbo]

Tranny fuild and oil is the same.

Oh contrare mon frere! Tranny fluid and oil are NOT the same thing. What no one has asked him is what type of trans he has? If it is an auto then buy auto tranny fluid. If it is a manual then you would want to use a full synthetic 85/90 GL4 or higher (premium would be Syncromesh 85/90 full synthetic). When was the last time the car had that service? If youve never had it done personally then do it. And fluid level is equally important. If its too full then the car wont want to shift properly and will eat syncro's. Too low and, you get the idea. Chances are that is your tranny. And the sound you are hearing is normal. It would be the sound of gear teeth meshing. Try taking it to a dyno and stand there while it gos through the gears till you find it. I hope some of this helps. But Im 100% serious about the fluids

 

[eclipse90gsxt]

Tranny fuild and oil is the same.

Oh contrare mon frere! Tranny fluid and oil are NOT the same thing. What no one has asked him is what type of trans he has? If it is an auto then buy auto tranny fluid. If it is a manual then you would want to use a full synthetic 85/90 GL4 or higher (premium would be Syncromesh 85/90 full synthetic). When was the last time the car had that service? If youve never had it done personally then do it. And fluid level is equally important. If its too full then the car wont want to shift properly and will eat syncro's. Too low and, you get the idea. Chances are that is your tranny. And the sound you are hearing is normal. It would be the sound of gear teeth meshing. Try taking it to a dyno and stand there while it gos through the gears till you find it. I hope some of this helps. But Im 100% serious about the fluids

He mentioned, "only in gear mainly in gears 1/2/3." so I figured it a standard. Probably it was what your saying, like I and he said, change the tranny fuild.

 

[upshiftN]

thanks for that little tranny info stuff.. but as i was driving around for a while tonight i noticed now more things with this. Without giving it gas, like going down hills in 3rd, i still hear it, it's not only at around 2000 rpms.. it's all the way up to 3000 rpms. It has gotten ever so sligthly louder too. Just easier to hear now, now with it actually being loud. And i could also hear the same sound when i hit bumps and the car rattled.. i hear the faint sound that i've been hearing coming from the same area. I plan on changing my tranny fluid, but i dunno if it's still the sound i am hearing. Ever heard what the sound is like when you have a metal wire... and have a staple or a paper clip around it... just spinning there, that's what it sounds like... SO i dunno.

 

[upshiftN]

NOT* with it actually being loud. (spelling error from last post)

 

[eclipse90gsxt]

When you change the tranny fuild, make sure you watch it coming out to see if any metal pieces come out, when its draining.