High CO at High RPM

This condition indicates abnormally high Carbon Monoxide with low or normal Hydrocarbons during cruise (2500 rpm).


POSSIBLE CAUSE ACTION


Faulty bowl vent/canister purge system Check Evaporative System. See EVAPORATIVE
CONTROL SYSTEM in TESTING PROCEDURES.



PCV malfunction Check PCV system. See POSITIVE CRANKCASE
VENTILATION SYSTEM in TESTING PROCEDURES.



EGR malfunction Check EGR system. See EXHAUST GAS RE-CIRCULATION SYSTEM
in TESTING PROCEDURES.



Restricted exhaust Check for plugged exhaust system. See CATALYTIC
CONVERTER in TESTING PROCEDURES.



Incorrect Spark Advance Check Spark Controls (EST, ESC, etc...).



Fuel metering malfunction

Carbureted Check carburetor passages, bleeds
and restrictors - Internal leaks,
float level, metering rods, and gaskets.
Replace or rebuild if faults are found.



Fuel Injected Check fuel pressure.
Perform injector balance test.
Inspect regulator operation
(check vacuum line and return hose),
Service Fuel Injectors (Pressure clean).