2G Boost leak test

[MasterMatt209]

I'm doing a boost leak test but my system won't hold any pressure at all. Am I supposed to cap something off or soemthing? Idk why it won't hold pressure

 

[thejollyrancher]

Not really. Your boost control vacuum line should be pinched off. But you probably have bigger problems if youre holding no boost at all. How do you have it set up?

 

[MasterMatt209]

Not really. Your boost control vacuum line should be pinched off. But you probably have bigger problems if youre holding no boost at all. How do you have it set up?

All I did was make a boost leak tester and the tester has no leaks at all. I hooked it up to my turbo and that's all I did, do I need to do anything else?

 

[MasterMatt209]

My first time doing a boost leak test so maybe I'm just doing soemthing wrong

 

[gieri002]

It's as simple as that. You very well could have that bad of a boost leak! Where is the air going? It has to be exiting somewhere. I know it sucks but you're going to have to track it down!

 

[MasterMatt209]

Well when I turn it off I hear some air escaping near the throttle body but Ive been searching near the throttle body for an hour and haven't found the leak

 

[2gmitsueclipse]

Use warm water and soap in a spray bottle. Bubbles will form where the air is escaping. I would bet that your shaft seals are leaking if you are holding little pressure. Also check the injector seals on the intake manifold as well.

 

[MasterMatt209]

I've been using the soap, where are the shaft seals located? I had to replace my throttle body gasket yesterday and today I had to get a new o ring for the biss but somehow the throttle body is still leaking

 

[gst-turbo]

Use a gasket and rtv sealant for the throttle body

 

[Rev_olution]

Your system isn't holding pressure because your engine isn't in top dead center. the air is leaking through the valves; . Put it in top dead center, and then voila

 

[MasterMatt209]

Can you guys see those metal ring type things in the pictures I just added? They're creating tons of bubbles how do I fix that

 

[MasterMatt209]

What the hell is top dead center and voila?

 

[2gmitsueclipse]

The shaft seals are on each side of the TB. There is one under the TPS, and the other is on the opposite side where you will find the throttle cable connected.

 

[Rev_olution]

Top Dead Center, is when your pistons are at the top position, and at its furthest point. When so doing, the valves close.
Good video:

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voi·la
vwäˈlä/
exclamation

1. there it is; there you are.
   

 

[2gmitsueclipse]

Can you guys see those metal ring type things in the pictures I just added? They're creating tons of bubbles how do I fix that

That could be the shaft seal, or the TB gasket on that side.

 

[Rev_olution]

Guys stop it, it isn't working because his car isn't at TDC. It's like pouring water in a cup that has a hole in the bottom.

 

[2gGst98]

Well it's creating bubbles, so he does have a leak their. But yea make sure you are at 30* Top Dead center per this thread.

http://www.dsmtuners.com/threads/does-the-motor-need-to-be-tdc-to-do-a-boost-leak-test.307590/

Saved this thread when I did my first test. Post #4 is step by step instructions.

 

[97_4g63t]

Can you guys see those metal ring type things in the pictures I just added? They're creating tons of bubbles how do I fix that

That would be your shaft seals. Try spraying the other side, it'll probably leak out of the sensor.
http://www.ca.dsm.org/FAQ/tb-shaftseals.html

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don't forget to check your brake booster, injector seals, bov adjustment and fpr adjustment. Also listen inside the car if you have an aftermarket boost gauge.

 

[2gGst98]

That's a good video, I like.

 

[luv2rallye]

His pics clearly show air leaking (bubbles) at the throttle body shaft seals.

And Rev_olution, on our engines at any TDC you have 2 cylinders that have both intake and exhaust valves partially open (see "Intake-exhaust valve timing turbo" pic shown here: http://www.dsmtuners.com/threads/bo...th-boostpro-net-tester.169435/#post-152554139)

 

[MasterMatt209]

I'm kinda of confused.. But I have a question what do I need to rebuild my throttle body? Or at least where can I get nee shaft seals

 

[2gGst98]

Here is the shaft seals
https://www.extremepsi.com/store/product.php?productid=22407

I should order them myself, but the end of the video (posted by 97_4g63t) has the part numbers if u want to go with another vendor.

 

[luv2rallye]

Here's how to replace them:
http://www.dsmtuners.com/threads/91-94-throttle-body-shaft-seal-replacement.245124/#post151053750
or
http://www.ca.dsm.org/faq/tb-shaftseals.html

Be careful removing/re-installing the tiny screws on the throttle plate - they strip easily.

 

[LaMont Randell]

That would be your shaft seals. Try spraying the other side, it'll probably leak out of the sensor.
http://www.ca.dsm.org/FAQ/tb-shaftseals.html

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don't forget to check your brake booster, injector seals, bov adjustment and fpr adjustment. Also listen inside the car if you have an aftermarket boost gauge.

What do you mean listen inside the car if you have a after market boost guage?

 

[97_4g63t]

What do you mean listen inside the car if you have a after market boost guage?

The line running from a vacuum/boost source to your gauge. I've had it leak inside the cab. Just had to buy a new Ferrell and reconnect it.
This is what I'm talking about
http://www.google.com/imgres?imgurl...ch&client=ms-android-verizon&ved=0CB8QMygDMAM