Boost Leak Near Head

[Sparky206]

I've been searching around for a boost leak for a while now, causing slow spooling and general lack of power.

I've pressurized up the intake to about 12psi and found a few small leaks but nothing major. If i pressurize to 12psi, it will slowly drop about 1psi every 10 secs till about 4 psi, then it will take longer. I can hear some air flowing somewhere around the head. Sounded very much like it was coming from the spark plugs, so i checked them and 2 bubbled a bit of water, but a little tighening and it stopped. The noise is still there, most prominent if i put my ear around the spark plug valley, but still very hard to get a direction on it. Im almost certain no more hoses are leaking, so where else could i be loosing pressure?

Thanks

Edited February 10, 2012 by Sparky206

[JonnoHR31]

motor might have stopped in a position where both the inlet valves and the exhuast valves on 1 cylinder are slightly open. or the inlet valves are open and its slowly leaking through the rings.

[SargeRX8]

When you do a pressure test on the intake you don't open your throttle. Leave it shut, the throttle is sealed. If you open the throttle you will leak air as the are will flow through the head and out the exhaust. Almost all cylinders will be open it is impossible to shut them all at the same time. Are you testing with open throttle?

[JonnoHR31]

even with the throttle shut you'll still lose pressure through the idle air and possibly even the throttle body itself depending on the stopper screw and condition etc.

[Manuel Kasko]

Also use a bit of hose attached to a funnel

Funnel to your ear and use the hose end to scan around that area

Makes it easier to pin point the exact noise

[SargeRX8]

even with the throttle shut you'll still lose pressure through the idle air and possibly even the throttle body itself depending on the stopper screw and condition etc.

Do basically you will always lose pressure it's just about finding the leaks pre throttle body?