Pinhole leaks can sometimes be repaired with epoxy (e.g. JB Weld), if they really are pinhole sized leaks. Since pressure is a function of force and surface area (e.g. pounds per square inch), tiny leaks usually won't apply enough force to dislodge epoxy (not in my experience anyway).

 

id say to give jb weld a try as well. super glue will more than likely melt. i used jb weld on my IC pipe where I have my meth nozzle screwed in to stop it from leaking boost/meth....it works just fine

 

Nice article

 

great info everyone! i should have done this prior to my tune. i only did 338 whp/367 tq, 91 pump on a mustang dyno and my power drops dead at 5500. everyone tells me i have a bad boost leak. i wish i would have read this article prior, it would have saved me alot of headache and money.

 

what about all the vac lines off the intake manifold do u cap these or leave them as is and pressurize

 

Leave as-is and pressurize. Recommend putting zip-ties on all vacuum lines, esp the FPR vacuum line.

 

ok thanks

 

Hello, I am kinda confused here so I hope you guys can help me out

1. Is it ok to use a small electric tire inflator to do the boost-leak-test? My electric tire inflator has a gauge on it and it will not go more than about 7 psi!

2. I hooked it up straight to the turbo outlet house and still only 7 psi... is it because of the compressor?

 

No, you need one that can pressurize to the boost your making or a bit higher.

Athanasios

 

Ok so basically the tire inflator can't "flow" enough correct? Also, I am kinda confused as to how pressure can be built up in the intake mani and head since some of the valves will be "open" ??? Doesn't this mean that some air will "leak" back out of the exhaust side of the head?? Thanks!

 

Indeed the tire inflator is too small for the job.

The closed throttle plate leaves the only path for air to the manifold through the IAC, which is why you see any pressure at all. If the TB is opened, some air will leak through the intake valves into the cylinder, and a portion of that will make it past the rings and exhaust valves.

 

Ok so I went and got an air compressor that holds up to 110 psi and pressurerized the system right at the throttlebody with the regulator set to 20 psi on the compressor. My boost gauge was still reading ZERO psi! Buuuuuuuut this time, I hear a very hollow hiss and sure enough there is a nice sized leak at my intake manifold gasket that I could even feel. I ordered a replacement oem gasket today so hopefully this would fix it.

Is this the reason why my turbo was only building 5 psi of boost? The car idled pretty good with a random VERY slight misfire. Is this why it had this slight misfire as well? Gasket was just old I guess...

 

So long as the TB is closed, the small IAC passage allows only a trickle of air into the manifold (didn't I say this already?). Your boost gauge is probably connected to the intake manifold. If you want to pressurize the manifold fully, hold the TB open as pressure is applied.

 

thanks for the vac hose diagram.

 

Could someone please tell me which lines I need to cap off? Is it on the FPR or the boost controller? Im running the AEM tru boost gauge/controller.