So what is the correct way to go about doing a vacuum leak test? I figured you could just pressurize the IM and cap off the TB? How much psi of air would i use though? Also is that the best way?

 

first off, what are you checking or trying to figure out?

 

They sell smoke machines for 'pressurizing' the intake with smoke. Where there is a leak you can see smoke coming out. Those machines are for professionals and are somewhere around $1000. Pressurizing with air is not going to help you. You can put a piece of vacuum line on a stethoscope and listen for leaks. That works pretty well but you have to have a trained ear.

 

Using compressed air is probably the cheapest and easiest way to do it if you already have the compressor. Do just as you said cap off the TB, use a vacuum port or brake booster for the air feed make sure to put a hose clamp on. Depending how big/small your compressor is, apply 20psi or how ever much to fill the manifold. Have a spray bottle of soapy water around and spray where you think you might be having leak. Bubbles should form where the leaks are.

 

20psi isnt too much? I know about the smoke machines but im having a hard time finding a shop locally that has one. I put on a new TB and had the top half of my IM off and now i have a high idle so im thinking vacuum leak somewhere

 

ask yourself whats the difference between pushing 20-30psi from a turbo and a air compressor......

 

it depends on what his car and setup his....Our smoke machine only uses 1-3 psi depend on what you set it at...however we dont usually use it for vacuum leaks. we use it for evap system leaks, which will be damaged if they see mor than a few psi....

to the op, if you just have a bad idle get a can of ether and spray each vacuum line and gasket one by one until the idle changes. dont move to quickly or you can misdiagnose it. if you dont find anything bleed the coolant lines that are attached to the IM.