Air/Fuel Mixture: Testing and Inspection

NOTE: The air/fuel ratio can only be checked. There is no provision for air/fuel ratio adjustment.

CO Port Locations:

1. Remove exhaust sample port bolts for right and left cylinder banks. (#1).

Exhaust Adapters:

2. Install BMW exhaust adapters 13 0 080 or equivalent, at the sample ports.
3. Run the engine until normal operating temperature is attained (>160°F).
4. Shut off the engine.

Oxygen Sensor Connector Locations:

5. From under the vehicle, disconnect the oxygen sensors.

WARNING: The exhaust system will be extremely hot!

6. Restart the engine.

The CO reading should be approx. 0.7 ± 0.5 %

If the CO level is too high check:
^ Fuel injectors
^ Fuel pressure
^ Coolant temperature sensor

If the CO level is too low check:
^ Intake system air leak
^ Plugged or defective fuel injectors

NOTE: Do not mix up the oxygen sensor connectors.