I know there's plenty of threads on this but this is fairly specific...
If I have a manifold leak of any kind my idle should be rough right?

I just finished a turbo inlet install and we mistakenly though we needed to loosen the manifold. Now I'm hearing a consistent hiss that' coming from what sounds like the side of the manifold closest to the intake box.
the hiss doesn't change at all when I rev it.

Thanks for any thoughts,
-Brian

 

Bump for any advice : )

 

Did you have the bolt order and torques specs for putting the manifold back on, if not I would get them (I can get them to you) and try to re-torque everything in the right order. You may have bent it if you didn't follow the proper procedure. It is alum IIRC.

 

most likely a vacuum leak if the idle is rough, especially since you were just installing the turbo inlet hose. you can have an exhaust leak on the manifold and the car will still idle well.

 

I was thinking intake manifold, thinking maybe he didn't know to cut his old turbo inlet out and shove the crap out of the new one in to fit. I was guessing he removed it for access to the turbo and inlet. I guess it could be his exhaust manifold but I would have thought he would have said headers, but the way I understand it if the intake manifold has a leak this will cause havok on the Mass air sensor and TB sensor and make it idle rough, but I am not an expert by far.

 

Thanks for responses guys,
What's up Davon? Long time no see : )

To re-iterate the sound sounds like it is coming from DIRECTLY below the coolant reservoir. The idle is NOt rough. I actually drove the car around and it drove just fine. The sound doesn't change at all when I rev the motor and if anything gets a tad quieter. It sounds like a constant "ssssssssssss" I had loosened the INtake manifold and havent touched the exhaust manifold.

bump for more thoughts : )
-Brian

 

Well if it's right below your coolant overflow tank than I would venture to say header leak. Join the crew Now if it's below the turbo coolant res than I say it could def be your intake manifold.

 

When you took it off did you torque it in order to spec? If not it's totally your intake manifold and might be bent now.

 

to narrow down your search for a vac leak the absolute best way is to borrow or spend a few bux on a small propane torch,obviously do not lite it. turn the propane on near were you think the leak is and have the car at idle, the idle will change rpm when you get the propane near the leak.

 

Somehow that doesn't sound smart at all... but maybe im wrong. I guess it makes some sense but propane in a hot engine bay...

 

yeah thats probably the worst idea ive ever hearrd.

DO NOT DO THAT TO FIND A LEAK

i responded to your forum on Nabisco, i still think you are hearing either your turbo, or possibly a new intake noise caused by the new inlet.

 

It's not the worst idea ev-- BOOM! *cough*hack* Maybe it is...

 

actually guys thats absolutly the best way,and industry standard vacum leak solution its called propane enrichment and most mfg's make kits that screw on to std small propane bottles

we just use the small torches because they are cheaper


http://www.highperformancepontiac.co..._analyzer.html

http://www.amazon.com/OTC-7148-Fuel-.../dp/B0002SR5N0

http://www.autobarn.net/xxxw-otc7148.html

http://books.google.com/books?id=Yn9...WFY#PPA1163,M1


http://books.google.com/books?id=qB2...qbrZXAUT1imE0M


research...then post..in that order

 

Ok guys I figured it out! and without using propane : ) my apologies to hank hill

If you are facing the engine bay from the front of the car:
Right in front of the coolant reservoir but down a little bit there is a tiny hose that runs from top front left of the intake manifold to whatever it is that the two pink bolts hold down on top of the fuel rail. The hiss I was hearing was the air coming out of the intake manifold through that tiny little hose and not going into whatever the gold colored device is that is in between the pink bolts.
I don't have a camera on me otherwise I would take a pic. Anyone know what the purpose of this hose is?
Either way I got it fixed!
-Brian

P.S. The reason I couldn't originally find it is because a ground connector that attaches to the top of the intake manifold was undone and tucked back hiding this hose behind it DOPE!

 

wow it's a good thing you found out the problem. did you floor the car at all or just go up in revs slowly? that hose leads to your fuel pressure regulator and as boost increases it helps fuel pressure go up. hopefully you didn't get on it too hard or you would have been running super lean.