Hissing noise near driver side firewall under hood

[Yipeekayea]

Trying to figure out if this is normal or not. When the car is at idle under the hood their is a very noticeable hissing noise above the driver side area near the firewall. Is this normal? It had a bunch of tape on it when I bought it which makes me wonder if somebody did a crappy repair job .. Can somebody identify this part for me?

 

[Majestic]

The hissing isn't normal. That tape looks like it was used to secure the hose back onto the broken plastic clip. I have a couple of places under the hood where I used zip ties for the same purpose.

 

[Yipeekayea]

Any idea what part that is?

 

[tothiel]

I've noticed this same noise on mine over the weekend. Haven't had much time to troubleshoot but if I put my hand over the bottom hose the noise is muffled.

 

[Yipeekayea]

Yeah it's the rubber hose beneath that long plastic tube. Right at the sharp bend near the brake booster. I had to it up with 3 layers of electrical tape wrapped around it and the noise is gone. I have no idea what this hose is called so I'm not even sure how to order it

 

[Yipeekayea]

I should say the noise is mostly gone....interesting is if I plug that plastic hose and start the engine it's whisper quiet...but when it's connected to that spider web of brake booster vacuum lines...the hiss is their but quiet. Now correct me if I'm wrong but could this be the reason the car feels a bit slower than normal? Slight boost leak? I'm seeing 13-14 pounds of boost WOT and 18-19 inches at idle. LMS 3 BAR tune

 

[Majestic]

I should say the noise is mostly gone....interesting is if I plug that plastic hose and start the engine it's whisper quiet...but when it's connected to that spider web of brake booster vacuum lines...the hiss is their but quiet. Now correct me if I'm wrong but could this be the reason the car feels a bit slower than normal? Slight boost leak? I'm seeing 13-14 pounds of boost WOT and 18-19 inches at idle. LMS 3 BAR tune

Wouldn't be any boost present in park. Maybe a vacuum leak, though.

 

[Yipeekayea]

No you misunderstood me....18 to 19 inches of vacuum pressure at idle....trust me I'm not that dumb...i home made a twin turbo foxbody 15 years ago using junkyard Volvo turbo.. tuned on a wideband o2..im well aware of boost versus vacuum

 

[Lammsho14]

Do you ever find the issue. I am having the same problem? Mine sounds like that little grey check valve is hissing like crazy. no sustainable boost after 2nd, just blows off repetitively. but I can't figure out what any of those parts are called to try and order.

 

[SHOdded]

Maybe one or both of the BOVs has a weak or broken spring/seal? Worth a check.

 

[StealBlueSho]

That grey piece is very thin... it’s normal to hear the air going through it...

Not normal to be dropping boost though...


Sent from my iPhone using Tapatalk

 

[Lammsho14]

yeah b/c you can hear air hissing all along that piping. but the hissing i believe is louder than it should be, idk. Just did a test, put it back to stock tune and the blow off was constant, with the 93p tune the blow off is short and repetitive.
Could be one of the BOV? ill have to check those