Tech Area

Air Filter Oil Bath

Question: Well I have a recuring problem with my air filter - it's always getting an oil bath. I have changed the PCV valve and breather valve numerous times trying to resolve the problem, but to no avail.

Am I missing or over looking something? Any help would be apreciated.

Answer: The PCV system usually clogs up in the passage cast into the bottom of the TBI on 84-86 4 cyl Fiero's.

Purchase a "spacer" gasket for the TBI (Felpro from AutoZone is inexpensive), remove the TBI unit, clean the PCV passage in the TBI and the EGR passage cast into the top of the intake manifold. Both passages "cake" solidly closed.

You may want to do a compression check. Any readings under 100 will indicate worn engine components (rings or valve seals) that create internal pressures.

However, if the passage under the TBI is closed, those pressures HAVE to come out somewhere, instead of going in to the intake manifold.

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