This is the '90 Si, 100% stock, 175k miles.
For about the past year everytime I shut the car off after it's been running awhile there is strange hissing sound coming from the engine bay. It lasts about 20-30 seconds then it's gone. I've checked everywhere and everything. I can't trace it to anywhere specifically. I thought it was the brake booster but that doesn't seem to be it. Replaced the PVC valve and some worn vacuum lines but it still does it. Any ideas?

 

what area in the engine bay, or is it coming from under the car or what?

have a friend turn off the car for you and listen... they make a stethascope (sp?) to listen to internal noise and clicking... may want to look into that

 

Somewhere behind the engine in the vicinity of the intake mani.
Can't really pinpoint it yet, it's not loud enough.

 

That sounds sorta like a booster. Mine hissed too, but only for about 5 seconds. 30 is a while. It could also possibly be a fuel pressure issue. Do you have a raw fuel odor?

 

Try putting your fingers near/on where the cyl. meets the booster after you turn the car off. If you feel air escaping, then I think you know wassup yO.

 

I noticed the same noise and mine was coming from my actual intake just letting out excess air I guess? Like someone said above have someone turn it off with your head under there and put your head right by your intake I bet thats what is making the noise. Do you have a short ram intake?

 

I was thinking that too, but according to him it is 100% stock, so that couldn't be it.

Plus an intake wouldn't do it for 30 seconds.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Ef ***** &raquo;</TD></TR><TR><TD CLASS="quote">That sounds sorta like a booster. Do you have a raw fuel odor?</TD></TR></TABLE>
Nope, no fuel oder to speak of, and did a pedal/booster check, pedal comes up strong and hard. I have NO clue to what it could be.
I checked to see if fuel tank pressurizes, seems fine. I give up.lol
Tha's why I posted. Couldn't think of anything else to check.

 

If the car was in my face I'd probably find the answer in a second.

 

Thanks, if I have nothing to do tomorrow, I'll take a ride down to Freehold. It's only about 35-45 min ride. LOL

 

Go ahead...I'm only two towns over.....j/k
Honestly if you need work done or a problem analxzed/fixed, the #'s in my sig.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Ef ***** &raquo;</TD></TR><TR><TD CLASS="quote">Go ahead...I'm only two towns over.....j/k
Honestly if you need work done or a problem analxzed/fixed, the #'s in my sig.</TD></TR></TABLE>
"Hi, Can I talk to Ef ***** please." ROFLMAO
Or "Excuse me Ma'am, is Ef ***** at home?" LOL
So THAT's where "muffdivingville" is?
My G/f asked if I knew where it was and I told her I never even HEARD of it. J/k Right next Eatingtown? LOL