Air/Fuel Mixture: Testing and Inspection
INSPECT CO/HCa. 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: 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). If the CO/HC concentration does not comply with regulations, troubleshoot in this order.
(1) Check A/F sensor operation.
(2) See the table for possible causes, and then inspect and repair.