Pressure testing intercooler piping

[xyster]

Might be a noob question...

I was pressure testing my intercooler piping today, with the idle hose disconnected and plugged, and the BOV/boost gauge hose to the nipple on the intake manifold disconnected and plugged...so the only connection between the pressurized piping and the manifold is the throttle body. Now, I had a significant amount of pressure in the intake manifold...is this normal, or do I have a bad throttle plate gasket or something?

[biosehnsucht]

The TB will never completely close, so it will 'lose' pressure there. Try blocking stuff on the manifold or disconnect from TB and block off that end of the piping.

[cadet]

I dunno about that, mine seals pretty well... if I put pressure to mine it will hold 5 psi+ for around 5-10 minutes easily.

[biosehnsucht]

then maybe you need to clean it because I don't think clean metal surfaces are going to mate well enough in the TB to make a perfect seal.

now it shouldn't leak much, but it will usually leak some..

another thing is one of the vacuum line fittings on the TB I think actually connects before the TB not after, so if you don't cap it you'll lose pressure there, I think its part of the evap crap.

[float_6969]

then maybe you need to clean it because I don't think clean metal surfaces are going to mate well enough in the TB to make a perfect seal.

now it shouldn't leak much, but it will usually leak some..

another thing is one of the vacuum line fittings on the TB I think actually connects before the TB not after, so if you don't cap it you'll lose pressure there, I think its part of the evap crap.

Yup, make sure you cap the one underneath the TB.

[sdtouge]

cap off the one under neath the tb for pressure sensing? or just cap it off no matter what? i have that one and another one under the tb both open, is that ok?

[cadet]

they leak...I've had a cap on the one under my throttle body since I installed it.

[sdtouge]

could i just loop them together or should i just cap them sepratly?

[cadet]

either would work, probably cap seperatly since they are different sizes...

[F3600]

When you pressure test you intercooler pipingsystem... whats is considered a leak.. ?

Mine at 10 psi stay on boost while slowly getting down .. at 5 psi the drop is super slow. Preferably .. we need zero drop.. but when the leak is bad for the engine so its stumbling and running bad ?

[cadet]

mine stumbles etc sometimes but I did it and mine wouldn't pressurize above 8 psi or so.. I realized that pressurizing the piping would cause the wastegate to open, and I wondered if that was causing that... but I don't see how the wategate opening would prevent it from holding boost...anyway so at 8 psi mine lasts for a long time, slowly dropping, and then at 5 it pretty much stops. So yeah, I'm thinking my loss is insignificant and wondering if my problems lie somewhere else.