Idle HC/Co Concentration Check
NOTE:
This check is used only to assist with idle HC/CO Diagnostics.
- Initial Conditions:
- Engine must reach normal operating temperature.
- Air cleaner installed.
- All pipes and hoses of air induction system connected.
- All vacuum lines properly connected.
- All fuel system wiring connections fully plugged.
- Transmission in P (Park) or N (Neutral) range.
- HC/CO meter calibrated and in hand.
- Run engine at 2500 rpm for approximately two minutes.
- Insert HC/CO meter testing probe into intermediate pipe at least 40 cm (16 in.).
- Check HC/CO concentration at idle.
NOTE:
Wait at least 1 minute before measuring to allow concentration to stabilize. Complete measuring within 3 minutes. If HC/CO concentration does not conform, see the following HC/CO diagnostic chart for possible causes.