Emissions - Testing Information

90cadillac12
NO.: 91-I-6

DATE: Sept. 1990
GROUP: 6E
CORP. NO.: 080101
SUBJECT: INFORMATION ON STATE EMISSIONS TESTING FOR ALL 1982-1991 MODELS


With more emphasis being placed on air quality, many states and municipalities have instituted vehicle inspection/maintenance (I/M) programs most of which include tail pipe exhaust emissions testing. Cadillac desires to do its part both in helping achieve cleaner air and in making sure our customers' vehicles are tested in a satisfactory manner.

A satisfactory exhaust emissions test includes making sure the vehicle's engine and emission control systems are fully warmed up just prior to conducting the test. An engine coolant temperature gage that reads operating temperature or a warm radiator hose does not necessarily mean the vehicle is ready to be tested. For example; although the engine coolant temperature sage may be reading at operating temperature, the catalytic converter may not be fully warmed up which may cause exhaust emissions levels to be artificially high and not representative of whether the vehicle's emission control systems are functioning properly. Therefore, if the vehicle has been turned off or sitting at idle for several minutes, even though the engine coolant temperature gage indicates the engine is at operating temperature, the vehicle should be driven on the road for a few minutes just prior to starting the official test to ensure that the engine and emission control systems are fully warmed up. An alternative warm up method that can be used and may be more convenient is running the engine at about 2500 rpm for two or three minutes with the transmission in park or neutral.