does anyone else get a light hissing from the front of the engine near throttle? i had changed the belts the other day and forgot to tighten the boot that connects the maf to the throttle, once i tightend it, it became quieter but still i can hear a light hiss...ideas?

 

Any vac leaks? Could it be the sound of the new belts? Does it change with engine speed?

 

depends what you call "hissing"

you can hear mine inhaling through the cai

 

^+1, that was the first thing I thought of.

 

Im gonna have to go with the majority here and say that it is just the normal sound your intake makes. Even with the muffler thingy on mine I still get a hissing sound and I know that the rest of my connections are tight and leak free.

Massey

 

i guess majority wins!, i put my hand all around where i was hearing it, and didnt feel anything, it doesnt increase with throttle, im a bit slow on the terms but CAI is??

 

Cold Air Induction

 

if its 95 or later make sure your vacuum for the opti is pluged in, also the suction for the air pump. they can hide from ya.

 

oho.. CAI learned a new one, i have a 2000 z28, opti is for lt1 no? airpump possibly, but im only hearing it when i put my ear near the maf/throttlebody, but if i stand on the passenger side, i dont hear it, nor when i close the hood and go back to driver side, i dont hear it, i think im just gunna drive it and see, would it throw a code for leaky vaccum?

 

the iac valve makes the noise on the lt1 and it carries to the filter. you should hear some hissing from the tb, theres air going through it.