HELP!!! Huge boost leak! No power~~

[knxkenix]

I recently did a boost leak test. but my gauage is not moving at all. i used to push 17 psi on T25. and it runs fine. i just had my clutch folk replaced. after that i am having huge boost leak. (or something.)
I hardly can reach to 70mph on 5th. My stock boost guage pressure builds up so fast. But when it builds up. I have knock back (lost power). The max psi i can reach is 9psi. And when i trun my AC (on start engine) and pull my steering wheel to one side. My car will stall.
For boost leak test. i search online. They said you should remove the PCV house. That which i believe is the metal tube sticking out on the left back side of the VC. Since i have aftermarket HKS BOV. I have nothing to remove from the BOV return line right?
Am i doing something wrong? Please help...

 

[top_end95]

Is the HKS vented or recirculated?
Also are you have using the stock gauge as a monitor while pressurizing the system? If so, just stop and pick up an acutal boost gauge.

This is the way to boost leak testing http://www.vfaq.com/mods/ICtester.html

 

[knxkenix]

Thanks for the reply, i have the HKS SSQV BOV vented i think the one that face out wards. I do have a aftermarket boost guage. The site above didn't show anything about removing PCV hose or the BOV return hose. IS the BOV return hose from the stock BOV back to intake? Cause i have aftermarket one. which i cap off the pipe from BOV back into intake pipe.

 

[95TalonOwner]

To put it short and simple: You NEED to recirculate in order for you car to run correctly.

 

[greeneclipse]

so if you did the boost leak test, what did you find?

if it's a "huge" leak like you say, then you should have an idea of where it's coming from?

 

[kenamond]

Thanks for the reply, i have the HKS SSQV BOV vented i think the one that face out wards. I do have a aftermarket boost guage. The site above didn't show anything about removing PCV hose or the BOV return hose. IS the BOV return hose from the stock BOV back to intake? Cause i have aftermarket one. which i cap off the pipe from BOV back into intake pipe.

The PCV valve is the metal thing sticking out the back left side of the VC. It is a 1-way valve that only lets air out of the VC. When you boost leak test, unscrew it from the VC. During the leak test, check that no air is coming out the PCV valve (because it's supposed to be 1-way). If it's leaking, get a new OEM one from a Mitsu dealer; the Autozone/Carquest ones don't work for our cars.

The BOV gets its "signal" from the IM. The small vaccuum line that goes from the IM to the BOV is what does this. When you let off the gas, the throttle closes, and all that boost from the turbo compressor has nowhere to go, so it wants to back up through your intake and surge your compressor wheel (not a good thing). The BOV keeps this from happening. When your butterfly closes, the IM goes into vaccuum. This vaccuum signal is transmitted to your BOV and yanks the sucker open so that all that backed-up boost gets dumped.

The MAS attached to your filter is used to tell the ECU how much air is entering the motor so that it can calculate the proper amount of fuel to inject. If you're not recirculating that dumped air from your BOV back into the intake pipe like it's supposed to, the air your engine thinks it's going to get doesn't get there, but the ECU still injects the amount of fuel it calculated, so you run rich. This makes the car run like shit after a shift or any time you let off the gas such that the BOV dumps metered air out of the system.

So recirculate your BOV back into the intake pipe.

There are minor things you should cap during a boost leak test, but if you have a huge leak, you should be able to track that down without capping any vaccuum lines. Attach the leak tester, pressurize to 20psi or whatever boost you are running plus 5psi and see how it holds the pressure. If you're using a compressor, set the regulator at 30psi or something so you don't blow the seals of your turbo. If it leaks down to 0psi in 1 second or can't even get up to 20psi (have someone watch your boost gauge, or add spurts of air and run around and peek at the gauge), you have a huge leak and you should be able to hear the air hissing out somewhere. Check all couplers, the IC (for holes), TB gaskets, BISS, BOV flange gasket, injector insulators (lower seals), PCV valve, and vaccuum lines. Use soapy water in a spray bottle to find the smaller/slower leaks (spray and look for bubbles), and use your ears to find the big ones. When you fix everything, repeat the boost test on a warmed-up motor to get a better seal on the piston rings and valve stem seals (they leak a fair amount of boost leak test pressure when the motor is cold). If you can pressurize to 20psi and have it leak down at a rate of about 1psi per second or less, any remaining leaks aren't going to cause the motor to run poorly, so if you're still having problems with a pretty tight intake, your problem isn't a boost leak (anymore).

And you shouldn't be running 17psi on a T25. That's too high, and it's very inefficient at that level which means you get much hotter air coming out of the compressor which lowers air density (less air in the cylinders=less power) and increases probability of knock (which will wear out your motor fast). It's harder on your turbo, too.

 

[knxkenix]

I figured that i have a huge leak by hearing a loud hissing noise comming from my right side of engine when i am driving. (Very loud).
When i pump air in it. The boost guage is not moving at all. This is what i did for my boost leak:
1. remove MAF and my intake pipe from turbo.
2. remove the PCV hose. (i didn't unscrew the valve off) Should I? or just remove the hose?
3. pumping the air in. (I went to one of my friend's auto shop. the pumps they use for tires and air gun)

Mods i have in my car. Maybe some of them will effect my testing.

Aluminium intake pipe
HKS BOV vented
Greddy EBC profec II
OBX catback
Autometer AFR, Boost Guage
Apexi Tach

My car also has very low rpm when the car is warming up. it goes from 500 to 800 back and forth till it compeletly warms up. when i turn my a/c on, it will stall when i stop sometimes or on a turn. I also smell gasoline on my tail pipe.