Boost leak test... WTF?!?
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
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
Jun 30, 2009, 11:18 AM
#18
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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...
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...
Jun 30, 2009, 11:20 AM
#19
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...
Jun 30, 2009, 11:21 AM
#20
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.
Jun 30, 2009, 11:25 AM
#21
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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...
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.
Jun 30, 2009, 11:31 AM
#22
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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.
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.
Jun 30, 2009, 12:00 PM
#24
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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.
Jun 30, 2009, 12:14 PM
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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.
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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