Engine Co/HC Emission Testing (5VZ-FE): Inspection
NOTE:
This check is used only to determine whether or not the idle CO/HC complies with regulations.
- INITIAL CONDITIONS
- Engine at normal operating temperature.
- Air cleaner installed.
- All pipes and hoses of air induction system connected.
- All accessories switched OFF.
- All vacuum lines properly connected.
- SFI system wiring connectors fully plugged.
- Ignition timing checked correctly.
- Transmission in neutral position.
- 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
- IMMEDIATELY CHECK CO/HC CONCENTRATION AT IDLE AND/OR 2,500 RPM
Complete the measuring within 3 minutes.
NOTE:When doing the 2 mode (2,500 RPM and idle) test, follow the measurement order prescribed by the applicable local regulations.
- TROUBLESHOOTING
If the CO/HC concentration does not comply with regulations, troubleshoot in the order given below.
- Check the A/F sensor or heated oxygen sensor operation (See CIRCUIT DESCRIPTION ).
- See the table below for possible causes, and then inspect and correct the applicable causes if necessary.
PROBLEM SYMPTOMS TABLE - CO/HCCO HC Symptoms Causes Normal High Rough idle - 5. Faulty ignition:
- Incorrect timing
- Fouled, shorted or improperly gapped plugs
- Open or crossed high-tension cords
- Incorrect valve clearance
- Leaky intake and exhaust valves
- Leaky cylinder
Low High Rough idle (Fluctuating HC reading) - Vacuum leak:
- PCV hose
- Intake manifold
- Air intake chamber
- Intake air connector
- Throttle body
- IAC valve
- Brake booster line
- Lean mixture causing misfire
High High Rough idle (Black smoke from exhaust) - Restricted air filter
- Plugged PCV valve
- Faulty SFI systems:
- Faulty fuel pressure regulator
- Clogged fuel return line
- Defective ECT sensor
- Faulty ECM
- Faulty injector
- Faulty throttle position sensor
- Faulty MAF meter