Boost leak test, help

[panamarojo]

Okay so I found a few leaks and fixed them. I here another leak it sounds like maybe behind the turbo and under exhaust manifold. Where would it be leaking from around there? I dont really see any hoses except for metal ones.

 

[panamarojo]

Is the waste gate rod suppose to move?

 

[frankenstein406]

you should be able to move the wastegate rod by hand.

 

[Jeff99GS]

Some types of Manual Boost Controllers have a small bleeder hole in them. Do you have this type of MBC? If so it will have a small leak from that bleeder hole.

 

[Rob10_99]

Yeah the bleeder MBC is a common issue with boost leak testing, I suggest bypassing it and running a line directly to the WG or cranking the MBC up, whichever is easier.

 

[95talonracer]

No cracks in the turbo?

 

[panamarojo]

I can't move the waste gate rod by hand, what would this be causing if it's broken? and i'd have to take the turbo off here in a couple days to see if it's cracked at all.

 

[Jeff99GS]

My wastegate is almost impossible to move by hand. Some of them have a very stiff spring. The Best way to tell if the Wastgate is working or leaking would be to take your air compressor and pump about 8-15 psi into the nipple of the wastegate. However much pressure it takes to open the wastegate is how much boost the car would have to make before it opens the wastegate flapper.

If you pump the Wastegate up to 10 psi and and you hear major leaking than the diaphragm in the wastegate could be ruptured or ripped.

I still think you may be hearing the MBC bleeder hole leaking. Do you have a MBC with a bleeder hole???? Did you ever check? If so then bypass the MBC with a piece of hose as mentioned above and try again.

 

[panamarojo]

There is no MBC, its stock. Cool, ill try and test the waste gate today and see whats up. I am wondering if it could be leaking out of the o2 housing gasket? could boost leak out of that? Also after pressurizing the system, how long for all the air to leak out?

 

[habitatguy187]

Go to 20psi and then you tell us how long it takes to leak all the way down. 5psi-0psi should take a loooooong time.

Also break out the soapy-water spray bottle and go to town before you pressurize. Leaks will show as bubbles, making it 10,000x easier.

 

[panamarojo]

Well i can tell you this much, around 15 PSI it takes a few seconds to drop to zero.

 

[Jeff99GS]

Are you setting the engine to 30 degrees after top dead center? This will keep all the Valves closed in the head. Otherwise all your pressure could be going out the exhaust.

If you are set to TDC then put a ratchet on the crank and hang it straight down in the 6 o-clock position. Now rotate the crank slightly in the clockwise direction till you get the ratchet in the 7o-clock area then stop. That's about 30* after TDC.

 

[panamarojo]

Yea I think that was the problem, I did it today and it wasnt leaking anymore, it took almost a minute for the air to drain out from 15 pounds. bout 45 seconds. Also the waste gate works fine.

 

[blade970]

So after you moved the crank the leaks weren't present anymore?

 

[panamarojo]

Yea, no more leaks. I think my problem is coming from my TPS

 

[rival879]

Nice tip, Jeff99GS.

May be common knowledge, but just in case, remember to only crank your engine forward due to the hydraulic tensioner on the timing belt.