The PCV (Positive Crankcase Ventilation) system is designed to regulate and remove fumes from the engine crankcase, and to alleviate crankcase pressure which could cause oil leaks or seal damage. The PCV system routes crankcase fumes into the intake manifold where they can be burned to eliminate harmful emissions into the atmosphere. The PCV valve controls the amount of crankcase flow volume depending on the engine's load. With large throttle openings (high engine loads), more blow-by gases are produced and the PCV system flows more oil vapor into the intake manifold. The PCV valve also functions as a check valve to prevent the intake manifold flow from reversing back into the crankcase when there is a backfire, or during periods of high manifold pressure (boost) during forced induction by a turbocharger or supercharger.
However, oil residue can accumulate inside the intake manifold, throttle body, intake track and even the air filter during aggressive driving conditions. There are various negative effects when excess oil vapor contaminates the intake system from the stock PCV system, such as:
• Throttle body and/or MAFS (Mass Air Flow Sensor) malfunction or failure.
• Air filter, intercooler (if equipped) and intake ducting contamination if oil pools and runs back out the intake system after engine shutdown.
• Reduced octane of the air/fuel mixture, which can cause detonation and the ECM (Engine Control Module) to retard timing, thereby reducing engine power.
• Excessive carbon build-up on valves, piston crowns, combustion chambers and spark plugs. This also increases the chance of detonation and power loss.
• Increased emissions & possible contamination of catalytic converters and oxygen sensors.
So, the bottom line is that excessive oil vapor in the intake manifold is detrimental to your engine. The fix is to install an Elite Engineering PCV catch can, and here's how!