exhaust is leaking boost
Apr 7, 2010, 07:58 PM
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exhaust is leaking boost
did a boost leak test and all the air is coming out thru the muffler ? even if i do it on the upper ic directly ....
has anyone had this issue before
im assuming a couple things but just want to double check with anyone
has anyone had this issue before
im assuming a couple things but just want to double check with anyone
Apr 7, 2010, 09:11 PM
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anoyne ever have a leak like this , all the air comes out thru the muffler on the boost leak , it dosent even pick up 2 pounds of boost on boost leak
Apr 7, 2010, 09:22 PM
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Apr 8, 2010, 05:22 AM
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sparky
i started to do the boost leak thru the turbo , it wouldnt pick up not even 1 pound , so thought it was the turbo leaking so i put the boost leak tester on the lower ic pipe , to see if it would pick up boost , results still 1 pound ...
then i thought i could be the intercooler so , i hooked up the boost leak tester after the intercooler , Upper ic pipe , and still 1 pound of boost
all the air is coming out thru the muffler u can hear it , and feel it big time ,
the test was done correctly , i used a huge air compressor ,
i dont know why there are no leaks on the ic or piping , but all the air is coming out the muffler , i know the motor dosent need to be TDC
Apr 8, 2010, 05:24 AM
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Apr 8, 2010, 05:30 AM
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I've hooked my boost leak tester up to the turbo to do ALL my boost leak tests. I wanted to identify and fix all possible leak sources. As stated earlier, try turning the motor over by hand and close the valves (although it should have stopped at a point that would have worked) and try again. If you have very long duration cams and the valves are staying open just cap the exhaust and pressurize that too! would help identify any exhaust leaks as well!!! LOL
Josh
Josh
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Apr 8, 2010, 09:12 AM
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Use the access hole in the passenger side fender area and put a ratchet or breaker bar on the crank bolt and turn it by hand. Don't forget to take the ratchet off before attempting to start the car. It will really mess some stuff up!!! I watched it happen to a car in my buddies garage. By the time I started yelling it was to late and he hit the key and tore some crap up!
Josh
Josh
Apr 8, 2010, 10:23 AM
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Boost leak test done at turbo inlet. Now if you hear air escaping from the exhaust it could be a few things.
1. exhaust valves are not closed on the cyls getting the air.
2. you have leaking valves. To test this first do a compression check (engine warm) to find the suspect cyl. Next do a leak down check on that cyl. You will need to crank the engine so that cylinders valves are all closed, IE like that cyl is on a compression stroke. pressurize that cyl to around 80 psi (some people do more) compair what is going in to what it is holding. Now listen for air escaping. Places to listen..1. oil fill hole in valve cover. that will indicate bad guides/seals 2. oil dipstick hole indicate possible bad rings (air getting past rings and into crank case) that is why you should do this test with engine warm to limit the possibility of air getting past piston/rings. warm pistons are expanded and sealing cylinders. The lower psi will also help reduce the chance of forcing air past the rings.
3. exhaust, this will indicate leaking exhaust valves. A little note that was mentioned..all cars have some cam overlap this will not allow for a huge diffrence in psi readings.
These are not all inclusive pinpoint tests but they will give you a direction to go.
1. exhaust valves are not closed on the cyls getting the air.
2. you have leaking valves. To test this first do a compression check (engine warm) to find the suspect cyl. Next do a leak down check on that cyl. You will need to crank the engine so that cylinders valves are all closed, IE like that cyl is on a compression stroke. pressurize that cyl to around 80 psi (some people do more) compair what is going in to what it is holding. Now listen for air escaping. Places to listen..1. oil fill hole in valve cover. that will indicate bad guides/seals 2. oil dipstick hole indicate possible bad rings (air getting past rings and into crank case) that is why you should do this test with engine warm to limit the possibility of air getting past piston/rings. warm pistons are expanded and sealing cylinders. The lower psi will also help reduce the chance of forcing air past the rings.
3. exhaust, this will indicate leaking exhaust valves. A little note that was mentioned..all cars have some cam overlap this will not allow for a huge diffrence in psi readings.
These are not all inclusive pinpoint tests but they will give you a direction to go.
