Vacuum/boost leak test - Confirm proper setup please

[gottadiesel]

I have read and read several threads related to different ways of testing for a vacuum/boost leak, some test more of the system then others...

My theory was that the more I can leave hooked up the better, otherwise you don't know if it is leaking where you took it apart and put back together after the test.

This is what I did, let me know if it was a good or bad idea...

Removed AFM sensor and sealed the two holes on top of afm body.
Removed the two T's that went to vents on valve covers for pcv system and capped them.
Isolated the EGR valve at the Plenum with a solid gasket to plug hole (1st round left EGR connected, found small leakage which I understand to a degree is normal, so wanted to isolate, as it distracted from hearing other issues)
Capped the afm body (intake side) after removing air filter
Capped the tailpipe.
Introduced air at the sample port on the bottom side of turbo (normally connects to the wastegate.

Set at 15psi, sprayed soapy water for visual and listened to see if I could hear anything...

Did it makes sense to do it this way, if not please explain so that I can make sure I am fully testing the system... I will not get into why on this thread... I have exhausted a couple of others already, I just want to make sure I am testing for leaks correctly and safely.

Thanks

 

[gottadiesel]

A wittle bump fer good measure...

 

[89supra7mgte]

wow you really are testing the whole system in and out. But i think you might be going too far. When i did mine i made a tester that plugged into inlet side of turbo and blocked off charge pipe right before tb. that tested the ic system. Anything from the exhaust manifold back will not be a boost or vac leak unless at the turbo mount. What you can do is pull the cams out hook everything back up except pcv system plug tb port and block (big hose) i think iirc this will test from turbo inlet to head, which is where escaping air or entering air will cause problems. You take the cams out so that all valves are closed and air pressure is stopped right at intake ports. Air will escape tb if not blocked but is normal with pcv system hooked up. Iscv should not leak air back out only pulls air in. if that helps any

 

[gottadiesel]

wow you really are testing the whole system in and out. But i think you might be going too far. When i did mine i made a tester that plugged into inlet side of turbo and blocked off charge pipe right before tb. that tested the ic system. Anything from the exhaust manifold back will not be a boost or vac leak unless at the turbo mount. What you can do is pull the cams out hook everything back up except pcv system plug tb port and block (big hose) i think iirc this will test from turbo inlet to head, which is where escaping air or entering air will cause problems. You take the cams out so that all valves are closed and air pressure is stopped right at intake ports. Air will escape tb if not blocked but is normal with pcv system hooked up. Iscv should not leak air back out only pulls air in. if that helps any

Thank you for your insight. Here were my thoughts behind it -

My concern with testing portions of the system, is that it leaves the connection that you undid to cap, as an unknown as to whether it is leaking or not.. i.e. disconnect the ic piping from the TB, what if that silicone coupler was leaking for some reason, it would not be apart of the test.

I know the exhaust is not a boost or a vac leak, but if I understand correctly, it can throw off the oxygen sensor, as at idle it could suck in fresh air, there by giving the incorrect values to the ecu. Also I found some minor leakage through the EM and Turbo flange that I could not hear, but would have for sure caused damage to gaskets over time...

Before the turbo, but after the AFM, no is not a boost leak, but it is un-metered air, again will cause a problem.

I am not sure I want to pull the cams to test for a vac/boost leak, seems a little extreme to me, If valves stay open and I cap the exhaust, yet my vents for pcv are open to keep the crankcase from pressurizing, I don't care if some of the air escapes through the cylinder wall and out the vents - do I? Correct me if I am wrong... it happens plenty so won't hurt my feelers

I guess just to clarify, I am asking mainly to see if anyone thought that my process would either do damage to something or would miss detecting a leak that could be causing lean/stutter issues...

Thanks

 

[IwantMKIII]

take off the intake and attach to the turbo and be done with it. Your leaks will show readily in the IC and vac system. Do not plug the PCV system or you may blow out your crank seal, ask me how i know.

 

[gottadiesel]

take off the intake and attach to the turbo and be done with it. Your leaks will show readily in the IC and vac system. Do not plug the PCV system or you may blow out your crank seal, ask me how i know.

Thank you for the info -

Correct they would show up easily enough, I guess I was trying to prove that the connection from my aftermarket Stainless Steel Intake (in place of accordion) was not leaking at any of the welds, or the silicone connections between it and the turbo and it and the afm body... perhaps not the right way, but that was my goal.

I plugged the T lines that would go into valve covers, not the valve covers... I could hear the little bit of air leaking through the valve cover vents as it should, so that should be the relief or escape so there is no pressure on the seals... in my mind it would be no different than doing a leakdown on a cylinder, you have some air escaping and going into crankcase... am I missing something or are we just not understanding each other?

Thanks

 

[gottadiesel]

IwantMKIII - I hope I did not sound like I was being an ass, as it was not my intention at all, after re-reading, thought it could be taken that way... I am not discounting what you were suggesting, but was explaining my reasons behind why I did it the way I did and if it is wrong, would be glad for some to correct me, I just want to know why it is wrong so that I can be sure to understand if I don't already...

Thanks again - if anyone has more experience in doing this type of test, I would greatly appreciate any other insight. I have been having a phantom issue and I want to be 100% sure that it is not an issue with air leaking in or out.