Boost leak test not holding pressure

[Zmcg1995]

So im doing a boost leak test. Hooked my tester right into the turbo and once i put air into the system, it holds up to 9psi and than it wont hold anymore... Once i stop putting air in it the pressure goes down a little over 1 psi per second maybe 1.5 psi per second. Shouldnt i be able to hold around 15-20 psi in the system? And should it stay in the system or will it go down once i stop putting air in?

[smoogs12]

Sounds like you've got a leak.

But yes, air will slowly bleed off. But this sounds like its happening a little quickly

[Zmcg1995]

Yeah but i cant really hear any leaks and i sprayed alot of tubes and cant seem to find any leak which i dont understand

[smoogs12]

You probably won't hit 20 psi. You dont need to.

Generally if its bleeds off at 1psi/sec or less then you are probably good to go. If you are more around 1.5-2 you might have a leak.

[Zmcg1995]

And also im kinda a noob so im not really sure what exactly i should be spraying. I mean im spraying the turbo inlet and some others but if someone could help me out on what i could spray that would be a big help

[pzr2874]

The BPV, boost tubes around the TMIC, etc...

[Agent_Orange]

Do you have an AP? Take a WOT log.

Any significant boost leak will be reflected in your boost levels, AFRs, and WGDC behavior.

[Zmcg1995]

There was a crack in the TIP. Couldnt hear it unless you had lots of air pressure. Ordered a corksport TIP couple days ago anyway so hopefully that solves it.

[Zmcg1995]

Also when doing a boost leak test do you just wanna check the things after the turbo for leaks or before aswell?

[Agent_Orange]

Originally Posted by Zmcg1995 Also when doing a boost leak test do you just wanna check the things after the turbo for leaks or before aswell?

Enough being nice to the brownie.

Stop asking stupid shit.

Search & Read.

Get an Accessport.

Donate.

/thread

[sidekick]

You want to check everything after the boost leak tester. Anything before the turbo = vacuum leak, anything after = boost leak, when in boost. The valve cover vent/PCV system have given me issues when doing boost leak tests, so try to rule that out when doing a boost leak test.

[Agent_Orange]

Originally Posted by sidekick You want to check everything after the boost leak tester. Anything before the turbo = vacuum leak, anything after = boost leak, when in boost. The valve cover vent/PCV system have given me issues when doing boost leak tests, so try to rule that out when doing a boost leak test.

Yeah, the VC vent should really be plugged while leak testing.

[lilred]

Originally Posted by Agent_Orange Yeah, the VC vent should really be plugged while leak testing.

Think I mentioned it in the other thread... lol

tapafuck

[sidekick]

Originally Posted by Agent_Orange Yeah, the VC vent should really be plugged while leak testing.

The downside is then the pressure just escapes elsewhere. I've had oil spray out in a fine mist from the pressure sensor on top of the VC.

[smoogs12]

I dont know how I would feel about all that positive pressure inside my CC.

[jm211]

Use common sense where things could leak. On a stock system there honestly isnt many and if you use common sense and a bit of due diligence leaks shouldnt be an issue.

Common spots are hoses, couplings and the clamps that hold them in place.

[sidekick]

Originally Posted by smoogs12 I dont know how I would feel about all that positive pressure inside my CC.

Yeah, it could cause issues with seals. At a minimum, the VC vent hose should be removed/plugged.

Part of my issue was the engine was completely cold, so the rings were not really sealed most likely.

[smoogs12]

Originally Posted by sidekick Yeah, it could cause issues with seals. At a minimum, the VC vent hose should be removed/plugged. Part of my issue was the engine was completely cold, so the rings were not really sealed most likely.

But if you plug it then the pressure cant escape.

I would think you would want to leave it open to reduce the pressure and the stresses on seals.

[sidekick]

Originally Posted by smoogs12 But if you plug it then the pressure cant escape. I would think you would want to leave it open to reduce the pressure and the stresses on seals.

Yeah, I'm not really sure on that. It makes sense to plug it to hold the pressure, so you can see if pressure is escaping at the normal 1PSI per second, but it also could damage seals if you do that. It could go either way, but I'm not sure what the "proper" procedure is. Ultimately, if WGDC, boost, and fuel trims look normal, it's not really necessary to do a boost leak test anyways.

[pzr2874]

as long as you don't go over 20psi on a BLT... you should be fine.

my experience

[Nitr0EngiE]

Next time light a cigarette blow ass tons of smoke into the tip and then pressure test, the smoke will come
Out the cracks

[jm211]

Gives me a reason to smoke, for the health of my car!

[pzr2874]

Or use a fog machine. Some shops use a smoke test as opposed to the soapy water... not that it makes a difference though.

[Nitr0EngiE]

Sm oke machine usually charge 40 for a smoke test, cigarettes can be had for free

[Agent_Orange]

Originally Posted by pzr2874 as long as you don't go over 20psi on a BLT... you should be fine. my experience

Right, for a good BLT you want between 15-20 psi, and extra mayo.

[86AmishMs3]

I generally do about 5psi over what I plan on running. So 30psi. Let the valve cover leak by the air (you will get a little blowby which is normal) and regulate your air so you maintain pressure, then search for leaks.