Testing intake for boost leaks.

Tom Mullane tmullane at snet.net
Sun Aug 3 13:02:12 EDT 2003


First off, my apologies for treading this well-beaten path, but a search of
the archives still leaves me with a few questions:

My 200 with the IA stage III chip rarely makes more than 1.6 bar of boost,
and occasionally during ah, "spirited" driving boost will drop to 1.1 bar
and refuse to go higher until I restart the car.  I did not read codes today
(laptop on loan) but in the past I have not found any.  This morning I built
a pressure tester to check the intake tract for leaks.  I did not remove the
crake vent or plug anything, I just popped the tester in and cranked in
about 10 psi of air.  Two leaks were immediately apparent; the crankcase
vent hose has a large hole in the bottom about 5 inches from its attachment
to the block, and the round black crankcase pressure regulator valve near
the back of the valve cover.  These leaks were whooshing enough air that it
was difficult to hear any other leaks.

My questions:
Several posts in the archives mention blocking the crank vent prior to
pressurizing; how/where is this done?  Is the pressure leakage from the
crankcase pressure regulator valve normal?  The leakage is from where the
"lid" is joined to the base.  Since this vent should be blocked anyway, do
these leaks affect boost?  (I'm guessing "yes" here.)

TIA for any incite you have...

Tom Mullane
Hartford, CT
1991 200Q
1991 CQ
1999 A6Q

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