Smoke After Boost Leak Test ??
Sep 15, 2009, 06:51 AM
#1
Smoke After Boost Leak Test ??
I recently did a boost leak test and for the first time opened the throttle body to test the TB seals....Well no TB seal leaks, but I did find an injector that was leaking...
Afterwards I started the car and it just blew tons of smoke. My car never has smoked, so I was quite concerned. After driving for a bit the smoke stopped, so I am guessing that pressurizing the system somehow put oil into the combustion chamber or intake manifold and just needed to be burned off.
My question is how did the oil get into the combustion chamber and why would it do so from the test versus normal driving under boost (what is the difference)? (I have a DC2 catch can, so I would have thought oil would have been trapped in the can if coming from the head and into the intake or IM.)
Thanks in advance!
Afterwards I started the car and it just blew tons of smoke. My car never has smoked, so I was quite concerned. After driving for a bit the smoke stopped, so I am guessing that pressurizing the system somehow put oil into the combustion chamber or intake manifold and just needed to be burned off.
My question is how did the oil get into the combustion chamber and why would it do so from the test versus normal driving under boost (what is the difference)? (I have a DC2 catch can, so I would have thought oil would have been trapped in the can if coming from the head and into the intake or IM.)
Thanks in advance!
Sep 15, 2009, 07:42 AM
#2
I recently did a boost leak test and for the first time opened the throttle body to test the TB seals....Well no TB seal leaks, but I did find an injector that was leaking...
Afterwards I started the car and it just blew tons of smoke. My car never has smoked, so I was quite concerned. After driving for a bit the smoke stopped, so I am guessing that pressurizing the system somehow put oil into the combustion chamber or intake manifold and just needed to be burned off.
My question is how did the oil get into the combustion chamber and why would it do so from the test versus normal driving under boost (what is the difference)? (I have a DC2 catch can, so I would have thought oil would have been trapped in the can if coming from the head and into the intake or IM.)
Thanks in advance!
Afterwards I started the car and it just blew tons of smoke. My car never has smoked, so I was quite concerned. After driving for a bit the smoke stopped, so I am guessing that pressurizing the system somehow put oil into the combustion chamber or intake manifold and just needed to be burned off.
My question is how did the oil get into the combustion chamber and why would it do so from the test versus normal driving under boost (what is the difference)? (I have a DC2 catch can, so I would have thought oil would have been trapped in the can if coming from the head and into the intake or IM.)
Thanks in advance!
Sep 15, 2009, 09:30 AM
#3
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You connected the boost leak tester at the maf position and didnt unplug the valve cover breather im guessing. it wont create smoke under boost because the intake to turbo isnt pressurized.
Sep 16, 2009, 09:24 AM
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Correct
9 out of 10 times that I take a tech call on a brand new leaking turbo the customer has just performed a boost leak test that actually caused a oil leak to occur. The boost leak test should always be performed such that the crank case is not pressurized. The crank case of the engine should never had positive pressure in it during actually running of the motor. If it does, then oil will squirt out of the turbo, even if the turbo is brand new.
The best way to ensure this is to open up the valve cover vent during the boost leak test and observe the leak air escaping easily. You should also hear the oil bubbling in the pan as the leak air going thru the compressor side air seal should be venting into the pan and out the valve cover.
This must be very easy to get wrong on the EVOX, it happens very often with the EVOX application.
BOOSTON!
Robert Young
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Sep 16, 2009, 02:47 PM
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You win the prize Sir!
9 out of 10 times that I take a tech call on a brand new leaking turbo the customer has just performed a boost leak test that actually caused a oil leak to occur. The boost leak test should always be performed such that the crank case is not pressurized. The crank case of the engine should never had positive pressure in it during actually running of the motor. If it does, then oil will squirt out of the turbo, even if the turbo is brand new.
The best way to ensure this is to open up the valve cover vent during the boost leak test and observe the leak air escaping easily. You should also hear the oil bubbling in the pan as the leak air going thru the compressor side air seal should be venting into the pan and out the valve cover.
This must be very easy to get wrong on the EVOX, it happens very often with the EVOX application.
BOOSTON!
Robert Young
9 out of 10 times that I take a tech call on a brand new leaking turbo the customer has just performed a boost leak test that actually caused a oil leak to occur. The boost leak test should always be performed such that the crank case is not pressurized. The crank case of the engine should never had positive pressure in it during actually running of the motor. If it does, then oil will squirt out of the turbo, even if the turbo is brand new.
The best way to ensure this is to open up the valve cover vent during the boost leak test and observe the leak air escaping easily. You should also hear the oil bubbling in the pan as the leak air going thru the compressor side air seal should be venting into the pan and out the valve cover.
This must be very easy to get wrong on the EVOX, it happens very often with the EVOX application.
BOOSTON!
Robert Young
Sep 16, 2009, 06:56 PM
#11
i did a boost leak test last week, just took the intake off plugged the mbc and pressurized. i hope i didnt damage anything cause my exhaust has a weird smell to it after the test almost smells like oil or a really rich smell?
Sep 16, 2009, 08:27 PM
#12
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on your intake, disconnect the line that routes to your valve cover. or you can skip all of this and just connect your tester directly onto your turbo and you wont have to disconnect any lines.
Sep 20, 2010, 08:49 PM
#15
In this case, is it necessary to change something on the turbo or is it just question of time before the car stop smoking???