Engine Mechanical: Co/HC: Inspection

HINT:

This check is used only to determine whether or not the idle CO/HC complies with regulations.

1. INITIAL CONDITIONS 
   1. Engine at normal operating temperature
   2. Air cleaner installed
   3. All pipes and hoses of air induction system connected
   4. All accessories switched OFF
   5. All vacuum lines properly connected
   6. SFI system wiring connectors fully plugged
   7. Ignition timing checked correctly
   8. Transmission in neutral position
   9. Tachometer and CO/HC meter calibrated by hand
2. START ENGINE 
3. RACE ENGINE AT 2,500 RPM FOR APPROX. 180 SECONDS 
   Fig 1: Inserting CO/HC Meter Testing Probe Into Tailpipe During Idling

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
4. INSERT CO/HC METER TESTING PROBE AT LEAST 40 cm (1.3 ft) INTO TAILPIPE DURING IDLING 
5. IMMEDIATELY CHECK CO/HC CONCENTRATION AT IDLE AND/OR 2,500 RPM 

HINT:

When doing the 2 mode (2,500 RPM and idle) test, follow the measurement order prescribed by the applicable local regulations.

If the CO/HC concentration does not comply with regulations, troubleshoot in the order given below.

1. Check heated oxygen sensors operation (See BASIC DIAGNOSTIC PROCEDURES ).
2. See the table below for possible causes, and then inspect and correct the applicable causes if necessary.
   Fig 2: CO/HC Troubleshooting Chart

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002