High HC & CO - at High RPM

This condition is indicated by abnormally high carbon monoxide AND hydrocarbon emissions during cruise (2500 rpm).

POSSIBLE CAUSE ACTION


Electrical misfires Check ignition system



Vacuum leak Check vacuum lines and routing,
check intake manifold gasket,
carburetor base, and vacuum components



Faulty canister purge system Check Evaporative System



PCV malfunction Check PCV system



EGR malfunction Check EGR system



Restricted exhaust Check Catalytic Converter



Initial timing incorrect Check Ignition Timing see "ADJUSTMENT PROCEDURES"


Incorrect Spark Advance Check Spark Controls see "COMPUTERIZED ENGINE CONTROLS"


Verify vehicle is operating in Refer to "COMPUTERIZED ENGINE CONTROLS"
Closed Loop at steady throttle for Self-Diagnostic procedures
(2500 rpm) and oxygen sensor
is working



Fuel metering malfunction Check fuel pressure
Perform injector balance test
Test regulator operation
(check vacuum line and return hose),
Service Fuel Injectors (pressure clean)