We recommend looking into why your Buick Century is dieseling first. Dieseling can be caused due to carbon built-up in the combustion chambers which burn hot after the engine is off, providing ignition for any unspent fuel. Dieseling usually occurs when an engine is running very rich, depositing unburned fuel on piston heads and valves. Or when a carburetor doesn't completely cut off fuel supply once the engine has been turned off.
Mike, ASE Advanced Emissions Specialist
posted by SmogTips Support 06-05-2012 10:21 AM