High CO at High RPM

DEFINITION
Abnormally high Carbon Monoxide with low or normal Hydrocarbons during cruise (2500 rpm)


POSSIBLE CAUSE ACTION

Canister purge system Check EVAP System. Evaporative Emissions System



[1][2]PCV malfunction Check PCV system. Testing and Inspection



EGR malfunction Check EGR system. EGR Valve



Restricted exhaust Check - Catalytic converter. Testing and Inspection
- Exhaust system for collapsed/
pinched pipes and muffler damage



Incorrect Spark Advance Check Spark controls (EST ESC)



Vehicle remains in Perform O2 sensor test
Open Loop at steady throttle refer to OXYGEN SENSOR TESTING/
(2500 rpm) DIAGNOSIS, TESTING AND INSPECTION PROCEDURES
in COMPUTERS AND CONTROL SYSTEMS



Fuel Injection system Check - Fuel pressure
refer to FUEL SYSTEM PRESSURE
TEST/ DIAGNOSIS, TESTING AND INSPECTION
PROCEDURES in FUEL SUPPLY AND AIR INDUCTION
- Regulator operation
(check vacuum line and return hose)
- Service Fuel Injector (Pressure cleaner)