2G Boost Leak!

[Whiteshadow]

Now i am confident enough to say i'm good at finding boost leaks and have a nice boost leak tester and so on...but the dsm has me stumped. When im boosting itll shoot up to 17 and drop down to 15 running off of the turbo...so i decided to put on a mbc and set it to 24psi....and imagine that i get the same result...24psi and then makes its way back down to 15psi. Id think a leak that big would probably blow my ears out itd be so obvious when i put a boost leak tester on...but its not. The boost gauge only makes it up to 9psi during the test as well which is weird...

1) Are there other things that could cause this problem other then a leak?Wastegate?

2)If it is the wastegate(internal) how can i test it? It seemed to be moving fine when i put pressure to it earlier...

 

[Irrational]

What turbo is on your car? It could just be a small turbo.

 

[laserspeeddemon]

Yes, for us to probably diagnois the problem, you must properly complete your information.

A 94 Eclipse N/T doesn't care about boost leaks.

 

[Whiteshadow]

sorry about that...my N/T did care about boost being that i swapped in the 4g63t...*updated*

I am running a PTE50 internally gated turbo and i have tried getting it to hold boost with and without the MBC and i get the same outcome. It didnt have this problem when i had the same setup on my fwd, if anything it would creep...im more worried with why i cant get more then 9psi on my boost gauge during the boost leak test and not hearing a sound in terms of leaks

 

[AlumRodLaser]

Big exhaust leak maybe? Do you have an adjustable wastegate actuator?

 

[Whiteshadow]

yea the wastegate actuator is adjustable...and i have tried that

 

[ddavisaf]

Have you sprayed down everything with soapy water? If not, try that. It will help you visually pin point leaks you may not be able to hear. Also, open the oil cap and listen for air there. If you hear air, rotate the crank 30° and try again. Keep doing this until you can't hear any air.

 

[Whiteshadow]

i shall give that a shot when i get the chance...i also bought "vacuum manifold" to get rid of any "T"s and get everything a clean source...

 

[Chaddycakes21]

How do you rotate the crank 30 degrees?

 

[steve]

I'm more worried with why I can't get more then 9psi on my boost gauge during the boost leak test and not hearing a sound in terms of leaks

What are you using to pressurize the intake. If it's a compressor you must have some big leaks somewhere.

How do you rotate the crank 30 degrees?

You rotate the crank until the timing mark lines up with TDC on the front cover than then rotate the crank another 30 degrees. If you can't visualize 30 degrees go get a protractor.
It's not that critical, as long as you make sure the engine doesn't have any cylinder in overlap you'll be ok to test.

Steve

 

[Whiteshadow]

What are you using to pressurize the intake. If it's a compressor you must have some big leaks somewhere.

yea we were using a compressor....i did notice that when we opened the throttle just to see if that would make a difference....air was coming out of the exhaust...at that point we opened the oil cap but felt nothing. Maybe i do need to rotate the engine...thatll be my next move.

 

[steve]

yair was coming out of the exhaust. Maybe i do need to rotate the engine...thatll be my next move.

If the engine happened to stop with a cylinder in overlap it's a pretty big leak. The air just rushes in the intake valves and out the exhaust valves.

Steve

 

[Whiteshadow]

im gonna feel stupid if that's the case. All of the knowledge i have learned and i get pwn3d by the good ol "overlap"....

(whiteshadow)

 

[ddavisaf]

Let us know what you find out.

 

[laserspeeddemon]

I was going to say to use soapy water. When I boost checkd mine, I heard boost leaks coming from LICP, but I sprayed the whole system anyway and found that the BISS Screw O-ring was leaking and both TB gaskets were leaking, I had no clue.