Air/Fuel Mixture: Testing and Inspection

INSPECT CO/HC
a. Start the engine.
b. Rev the engine at 2,500 rpm for approximately 180 seconds.
c. Insert CO/HC meter testing probe at least 40 cm (1.3 ft) into the tailpipe during idling.
d. Check CO/HC concentration at idle and/or 2,500 rpm.

HINT:
^ Complete the measurement within 3 minutes.
^ Check regulations and restrictions in your area when performing 2 mode CO/HC concentration testing (engine check at both idle speed and at 2,500 rpm).

e. If the CO/HC concentration does not comply with regulations, troubleshoot in the order given.
1. Check heated oxygen sensor operation.





2. See the table for possible causes, and then inspect and repair.