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 (h) Transmission in neutral position
   8. Tachometer and CO/HC meter calibrated by hand
2. START ENGINE 
3. RACE ENGINE AT 2,500 RPM FOR APPROX. 180 SECONDS 
4. INSERT CO/HC METER TESTING PROBE AT LEAST 40 cm (1.3 ft) INTO TAILPIPE DURING IDLING 
Fig 1: Inserting CO/HC Meter Testing Probe Into Tailpipe During Idling
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
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 INSPECTION ).
   2. See Fig 2 for possible causes, and then inspect and correct the applicable causes if necessary.
   Fig 2: CO/HC Problem Symptom Chart

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002