Engine Co/HC Emission Testing: Inspection

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

INITIAL CONDITIONS
1. Engine at normal operating temperature
2. Air cleaner installed
3. Air 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 check correctly
8. Transmission in neutral position
9. Tachometer and CO/HC meter calibrated by hand
START ENGINE
RACE ENGINE AT 2,500 RPM FOR APPROX. 180 SECONDS
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
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IMMEDIATELY CHECK CO/HC CONCENTRATION AT IDLE AND/OR 2,500 RPM

Complete the measuring within 3 minutes.

NOTE: When performing 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 conform to specifications, perform troubleshooting in the order given below.

Check the A/F sensor operation (See DTC P1130: A/F SENSOR CIRCUIT (BANK 1 SENSOR 1) ).
See the table next page for possible causes, and then inspect and correct the applicable causes if necessary.

Fig 2: CO/HC Problem Cause Chart
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002