I have a 94 z28 that is pretty much stock besides the exhaust and K&N intake. While i am driving straight down the road, i hear this constant hissing noise that almost sounds like the noise that comes from your speakers when ther're turned up loud but nothings playing. It sounds like its coming from the rear of my car. The strange part is, is that when i make a turn or turn the wheel sharp, the noise completly cuts out, but then when i continue going straight ahead again, it comes back. Does anyone have any idea what this could be?

 

My first guess was fuel pump since they are pretty loud on these cars and easily heard, especially from outside, but the fuel pump wouldn't care if you are turning.

 

ive got the same thing.....i always thought it was my subwoofer

 

probably the air sucking into that k@n intake..... just a guess but it very well could be that......

 

From your description, it sounds like your rear brakes. The pads may be contacting the rotors, producing the brushing sound. Nothing major, pretty normal operation. Other than that or the previous suggestion, you may have a plastic bag stuck to your axle... good luck john

 

how bout a small exhuast leak, you said you had an aftermarket exhaust and if you are only using clamps it is a good possibility that there could be a leak

 

I have the same thing with my car, i always thought it was insignificant since the noise was barely audible. In fact i didnt even notice it until a friend rode with me in the car! And my car is 100% stock.

Could it be a serious problem?

 

i got the same problem. got a 95 t/a s speed
what do you guys own?? maybe its a tranny thing??

 

Gotta throw my .02 in...

My vote is the fuel pump noise.

 

if it is constant, coming from back of hatch, then fuel pump.. every 4th gen i know you can hear it... nothing wrong if that's all it is.

 

Sounds like it could also be something with the rear end. I had a similar noise when by pinion bearing went (twice). Mine did it around corners though but yours could just be a different bearing. If it's the rear you could be damaging parts by driving it.

 

Ok the past few days it's been getting colder and the noise has been getting louder, I really don't think it's normal...

I don't know how to describe it besides how the original poster did. It sounds just like as if the radio is on and the volume is up full blast, but there's no music playing, except the radio is NOT on.

Anyone have any ideas?

Thanks.

 

I'm problably way off base here,but you mentioned the noise stops when you turn left or right.There is a slight hissing noise(normal)when you turn the wheels all the way left and right,it's a valve in the rack system.Is your rack and pinion leaking?Or does the rack lock up on you when the car is cold?Might be rack time.(rebuilt).Hope this helps.

 

That's what I'm thinking. The fuel pump would not change sound when making a turn, full tank or empty. When turning one wheel is rotating slower than the other. I'd say rear end.

 

Change your rear fluid and see if that does something. If not I would say brakes which is normal... I believe Brent Franker has a guide to changing the rear diff. fluid (which is a pretty mindless job anyway). Originally I would have said fuel pump but it doesn't match with your symptoms.