Idle and/or 2,500 rpm HC/CO concentration check method¶

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

      Hint

      All vacuum hoses for EGR systems, etc. should be properly connected.

   6. EFI system wiring connectors fully plugged

   7. Ignition timing set correctly
   8. Transmission in neutral
   9. Tachometer and HC/CO meter calibrated and at hand

2. Start engine.

3. Race engine at 2,500 rpm for approx. 120 seconds.

   

4. Insert HC/CO meter testing probe into tailpipe at least 40 cm (1.3 ft).

5. Check HC/CO concentration at idle and/or 2,500 rpm.

   Complete the measuring within three minutes.

   Hint

   When performing the 2 mode (2,500 rpm and idle) test, follow the measurement order prescribed by the regulations.

   

If the HC/CO concentration at 2,500 rpm does not conform to regulations, try the following procedure.

Race the engine again at 2,500 rpm for approx. 1 minute and quickly repeat steps 4 and 5 above. This may correct the problem.

Troubleshooting¶

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

1. Check oxygen sensor operation. (See page FI-173)
2. See the table below for possible causes, and then inspect and correct the applicable causes if necessary.