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lucittm lucittm is offline
Manassas, VA
 
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Join Date: Apr 2007
Posts: 1,211
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I'm moving to Iowa...

Actually, the air injection system added air to the unburned exhaust gases in the six exhaust ports and the cat when the engine was cold to reduce emissions. This is because the cat does not work until it is warmed up. The air injection system has check valves that are supposed to prevent exhaust from leaking back through the system, but they often fail after years of use.

A failed check valve in the exhaust port side allows back flow of exhaust pressure that would otherwise be directed to the turbocharger resulting in a loss of boost for a given rpm.

The air pump body is made of cast iron and is quite heavy. I have to ensure that my car is up to operating temperature and that the technician will not look too closely at my engine when connecting the emissions computer to the spark plug wire.

Mark
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1991 964 Polar Silver Metallic Turbo Coupe
Old 10-01-2008, 06:47 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #17 (permalink)