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Boost leak test... WTF?!?

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Old Jun 30, 2009 | 11:14 AM
  #16  
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not much will get past the throttle body plate if any. Mine seems to seal pretty damn tight.

Point is though, a valve is open if its getting thru the exhaust. Why care? If you are getting the far and feel its flawed, this is not the test to tell you.
If a valve is ****ed, either put it to TDC and retest or do the proper test to diagnose a leak from the head to exhaust
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Old Jun 30, 2009 | 11:17 AM
  #17  
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i just think on the cammed evo the exhaust valves are opened... as far as the stock cammed evo.. there shouldnt be like symptoms... not being able to compress more than 2 psi... i cant think of any other reasons...
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Old Jun 30, 2009 | 11:18 AM
  #18  
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Originally Posted by *constant_boost
before you post up something THIS retarded, the throttle plate doesnt need to be opened for air to get passed it... so if you are just shooting in the dark, youre an idiot and im going to start qupting all of you that try to even SOUND like you know what youre talking about... a boost leak test does more than the "charge pipes and boost lines"... FURTHER if you knew so damn much, you would know that even with the throttle closed that there are still ways for the air to go around... i.e. the t/b doesnt completely seal off the intake manifold... look whos laughing now... i asked for advice not silly amatuers posting about things they THINK they know...


now as far as the wastegate flapper goes, i dont know how it could be, only 2 psi of air pressure is making it into the system before the leak occurs... an opened valve COULD be it, and the wastegate COULD be it... i will have to do some more trials and error when i get home.. i just dont see how both of the evos are leaking out of the exhaust...


PLEASE no more attempted flaming posts... im not new to the evo world, nor do i care to hear about how uneducated you REALLY are...


thank you to those whom had decent ideas...
werd, don't worry about putting it on jackstands, just bump it with the key till it's close, then put it in 5th gear and nudge the car forward till it lines up at TDC (engine off of course). I doubt both would have bent valves so the most likely thing is the valves are open because it's not at tdc.
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Old Jun 30, 2009 | 11:20 AM
  #19  
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one more thing... i have to pay attention past the throttle body right now, because one of my biggest problems is that the pressure is leaking out of my exhaust from what i believe to opened valves.. if my car was holding pressure before the intake manifold then this post wouldnt exist...
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Old Jun 30, 2009 | 11:21 AM
  #20  
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Originally Posted by mad_VIII
werd, don't worry about putting it on jackstands, just bump it with the key till it's close, then put it in 5th gear and nudge the car forward till it lines up at TDC (engine off of course). I doubt both would have bent valves so the most likely thing is the valves are open because it's not at tdc.
i just find it weird how ive been able to do this before without needing tdc... or even checking... i seriously doubt that the car landed tdc every time i parked and have done it inthe past... but this is what imma try to do
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Old Jun 30, 2009 | 11:25 AM
  #21  
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Originally Posted by *constant_boost
one more thing... i have to pay attention past the throttle body right now, because one of my biggest problems is that the pressure is leaking out of my exhaust from what i believe to opened valves.. if my car was holding pressure before the intake manifold then this post wouldnt exist...

again. . . i dont know how many diff ways to say this, but if you think you have a boost least. Boost leak test it to the IM.
If you think you have a valve problem, then compression test it or leak down test it.. if it leaks down or loses comp in a cyl, then pull the head.

I think you are trying to use some goofy tests to fix a problem that might not even exist. Use the right test for the right symptoms and make your life easier.

I HAVE NEVER PUT A CAR TO TDC TO DO A BOOST LEAK TEST. take that for what its worth.
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Old Jun 30, 2009 | 11:31 AM
  #22  
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Originally Posted by AWD_Terror
again. . . i dont know how many diff ways to say this, but if you think you have a boost least. Boost leak test it to the IM.
If you think you have a valve problem, then compression test it or leak down test it.. if it leaks down or loses comp in a cyl, then pull the head.

I think you are trying to use some goofy tests to fix a problem that might not even exist. Use the right test for the right symptoms and make your life easier.

I HAVE NEVER PUT A CAR TO TDC TO DO A BOOST LEAK TEST. take that for what its worth.
i've never done tdc either, never had a problem, drive it around the block and try it out again, like stated earlier probably open exhaust valves.
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Old Jun 30, 2009 | 11:58 AM
  #23  
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do you think putting the motor at tdc will close all the valves in every cylinder?
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Old Jun 30, 2009 | 12:00 PM
  #24  
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Originally Posted by leecavturbo
do you think putting the motor at tdc will close all the valves in every cylinder?
exactly why I say dont make a boost leak test harder then it needs to be.
Its not meant to tell you if your valves are open. Its meant to tell you if you are leaking boost thru a seal or coupler.
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Old Jun 30, 2009 | 12:02 PM
  #25  
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i agree 200%... what im saying is.. if my car isnt holding pressure... i cant find a damn thing can i??? read the OP.. the exhaust is bleeding out my pressure building up from the boost leak test...
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Old Jun 30, 2009 | 12:02 PM
  #26  
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im going to hook my tester up to the i/m and see if i still have the same results...







completely off topic

im doing a compression test as well... i know which tests are meant for what..
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Old Jun 30, 2009 | 12:04 PM
  #27  
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From: Hayward
EGR hose is off.

Behind intake manifold, under the throttle body.

This will do exactly what you are describing

-Bryan
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Old Jun 30, 2009 | 12:08 PM
  #28  
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Originally Posted by GST Motorsports
EGR hose is off.

Behind intake manifold, under the throttle body.

This will do exactly what you are describing

-Bryan
THANK YOU!!! ill check it when i get home
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Old Jun 30, 2009 | 12:14 PM
  #29  
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From: Gulfport MS
It's not about TDC it's about the valves being closed.

Every time you shut off the car the engine is going to stop turning becasue of a compression stroke. At that point all the intake valves are closed on all the other cylinders unless it stops during the overlap event in the other cylinder that was nearing the top. I would think it would be pretty unusual for the compression stroke to get that near completion before stopping the engine turning over. That's why it's usually fine to just do it how it sits.
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Old Jun 30, 2009 | 12:17 PM
  #30  
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From: Gulfport MS
Originally Posted by GST Motorsports
EGR hose is off.

Behind intake manifold, under the throttle body.

This will do exactly what you are describing

-Bryan
Wouldn't it leak from the nipple on the back of the IM if that was the case? (I'm not looking at the car atm so i could be wrong )
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