boost leak test (blt)help

[97ebaygst]

there is probably a post on this some where but i couldn't find it.
I ran a blt on my 97 gst and found a small leak in my throttle body elbow gasket but I hear a loud one coming from somewhere in the intake region.
My problem is that i can't seem to find it. I spayed it down till it was soaking wet but still no luck.
I only hold about 2.5 pounds when I do the test and that leaks out right away. what could leak that much and still not be seen. Is there any suggestion that anybody could give me on how to spot a leak other then listening or watching for bubbles?
This might be a crazy question but is there a way to use smoke to to test it, being that smoke would be easier to see

 

[skatershawn]

well most shops that have an ACTUAL boost leak tester use smoke.. theres a shop here in austin that has one im thinking about taking mine to cause im having the same issue!

Did you spray you biss screw, the air nozzles on the throttle body, check the injector seals, the intake mani, and throttle body oring for the shutter!

 

[97ebaygst]

I just replaced the biss screw and o-ring. would I have to take off the throttle body to check the o-rings or is there a way to do it on the car.
I was thinking fuel injector seals but I can't see down there

 

[skatershawn]

To replace the o ring on the throttle body i am 98% sure you have to take it off!
Never done it, i just know its a common boost leak problem!
And you can always just replace the seals on the injectors to insure it!
It wouldn't hurt...!!
And you also just need to FILL your intake system with about as much psi you are running!

Say im running 16psi, when i do a boost leak test i will pressurize my intake to about 20psi to make sure there is nothing!

Good Luck,
Boost leaks are a B**CH!!

 

[2qik4u]

check the bottom side of your intake manifold gasket!!! 3 friends in the last 2 yrs have had a boost leak there. use soapy water to check it. other than that the throttle body is another culprit of phantom boost leaks. good luck!

 

[97ebaygst]

i'll check both of those out and I'll get back to you guys when its done.

let me also ask because i see different answer everywhere. other then the mbc what other hoses am I supposed to cap off?

 

[2qik4u]

anything that leads to open air. and i would shorten all the vac hoses that have any excess length. just by getting in there and doing somehing like getting rid of extra vac line could cause you to run across a leak in a line or even on something else. i always find something wrong when i start to tinker with it!

 

[BLINKY619]

may be the shaft seals on the throttle body.... mine had the same problem and replaced them and now runs perfect