MX-6 L4-1991cc 2.0L DOHC (1993)
Three-Way Catalytic Converter: Testing and Inspection
FAULTY CONVERTER SYMPTOMS
^ Poor power output
^ Idle speed drops
^ Engine stalls
^ Rattle in the exhaust
POSSIBLE CAUSES OF CONVERTER DAMAGE
^ Engine misfiring (bad spark plugs, ignition wires, connections, etc.)
^ Ignition timing out of adjustment
^ Straining engine (pulling a trailer, mountain driving, etc.)
^ High speed driving at high outside temperatures.
^ Using leaded or high sulfur fuel.
CONVERTER INSPECTION AND TESTING
Visual Inspection
1.
Visually inspect exterior of converter. If severe damage is noted, such as dented, crushed or rusted out shell, replace converter.
2.
Whenever converter is removed from vehicle, check ceramic element through exhaust inlet and outlet. If element is clogged, melted or otherwise
damaged, replace converter.
Functional Test
1.
Run the engine at 2,500 rpm for approximately 2 minutes to heat catalytic converter to operating temperature.
2.
Connect a surface temperature probe on exhaust inlet of catalytic converter and measure temperature.
3.
Connect surface temperature probe on exhaust outlet of catalytic converter and measure temperature. Outlet should be at least 100°F (38° C) hotter
than inlet.
4.
If temperature differential is less than specified, catalytic converter should be replaced.
Exhaust Restriction Checks
Manifold Vacuum Test
1.
Connect vacuum gauge to manifold vacuum source.
2.
Start engine and idle. Note vacuum reading, and record.
3.
Run engine at approx. 2,000 rpm with no load. Note vacuum at steady engine speed. If vacuum is less than previous (idle) reading by greater than
3" Hg (75 mmHg), a restricted exhaust system is indicated.
Exhaust System Back Pressure Check (Using Oxygen Sensor Mounting Hole)
