Anyone got any tips on quieting the cold air intake vacuum sound? (Page 1/1)
jaydaug2008 AUG 03, 09:43 PM
First off..I am running the stock setup cold air intake. It is just really loud and was wondering if there is any tricks people do to quiet this down.. Definitely sounds like a vacuum leak. I had the air filter out a few days ago and I am sure there is no gasket. didn't even know there was supposed to be one until I read a few articles on here...Will a new gasket and good filter help? Thank you all!!
Patrick AUG 03, 10:10 PM

quote
Originally posted by jaydaug2008:

I am running the stock setup cold air intake. It is just really loud and was wondering if there is any tricks people do to quiet this down...



And you still have the factory water separator (#6 below) in place? I don't notice any air intake noise on my Fieros.
greenturnedblue AUG 03, 10:44 PM

quote
Originally posted by jaydaug2008:
Definitely sounds like a vacuum leak



If it sounds like a vacuum leak, maybe its a vacuum leak 🤔
jaydaug2008 AUG 04, 06:50 AM
I have the V6. sorry I didn't specify.
theogre AUG 04, 09:12 AM

quote
Originally posted by Patrick:
And you still have the factory water separator (#6 below) in place? I don't notice any air intake noise on my Fieros.

Even then many fools break the wall inside saying get more air thru...

https://www.fiero.nl/forum/.../HTML/144683.html#p3

Or the muffler breaks often where it attach to a mounting bracket. You have to pull the inner fender and maybe the part itself to look.

Or if had "Holley" scoops etc the muffler can get big crap stuck in it and make noise too. OE grill block big crap but small sticky stuff could sit in the muffler and rest of plumbing below the filter.


quote
Originally posted by greenturnedblue:
If it sounds like a vacuum leak, maybe its a vacuum leak 🤔

Maybe but unlikely.
Vac leaks you can easy hear often make the engine not running well w/ high idle and other problems.

------------------
Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should.
(Jurassic Park)

The Ogre's Fiero Cave

[This message has been edited by theogre (edited 08-04-2022).]

Blacktree AUG 04, 02:10 PM
Like mentioned above, it's not uncommon for people to modify or delete the water separator. They think it's a choke point in the intake system (but it's actually not). If that's the case, drop me an email. I still have one of these, in the storage shed.

[This message has been edited by Blacktree (edited 08-04-2022).]

Rhodesia1977 AUG 04, 03:50 PM
I can hear mine on my GT too. Sounds like a tiny tiny jet sucking air. My son thinks it sounds cool so I have left mine alone. I think maybe it's normal.
Patrick AUG 04, 04:08 PM

quote
Originally posted by Rhodesia1977:

I can hear mine on my GT too. Sounds like a tiny tiny jet sucking air.



Nobody is suggesting that the factory setup eliminates all sound from the intake. I can hear mine making a sound too if my head is by the intake opening on the side of the car.

However, the OP states that his is "really loud". It might help to understand the OP's issue if we were informed just how close he needs to be to the intake for it to appear "really loud". Is it "really loud" for example while he's in the car driving it? And the OP still hasn't informed us if the water separator/muffler in his Fiero has been removed and/or tampered with.
armos AUG 24, 05:10 PM
I can hear a loud hiss while sitting in the driver's seat when I first start my car and let it idle. The noise (at least on my car) is from the IAC inlet, not the plumbing.
Tuning seems to be a factor - I notice that when my ECM enters closed loop operation (ie 60secs or so), the idle gets better and the hissing diminishes. If it was constant then it would bother me more.
So I guess maybe it's sucking more air with a poor fuel mixture, then closed loop mode fixes the mixture and the IAC partly closes, making it quieter.

If you take the intake hose off the throttle body you'll probably hear the hiss coming from your IAC inlet. If you put your finger over that inlet then the engine should stall immediately. If not then you have a vacuum leak.


A long time ago I set my throttle stop screw just open enough so it didn't catch in the bore, and at that position, the TPS reading seemed right in line with where it was expected to be with the throttle closed, so I left it like that.
Maybe if it was more open then the IAC wouldn't have to suck as hard and would be quieter. I haven't tried.
Messing with that screw is a controversial topic here. Many believe you can screw things up by messing with it. I think it's not that critical, but that's just my opinion.
If the screw is still entombed under a seal then don't mess with it.