Jetta III L4-2.0L (ABA) (1995)
Catalytic Converter: Testing and Inspection
Symptoms of a faulty catalytic converter are:
^
Poor power output
^
Idle speed drops
^
Engine stalls
^
Rattle in the exhaust
The converter can be damaged by:
^
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.
THE CATALYTIC CONVERTER CAN BE CHECKED IN SEVERAL WAYS
VISUAL INSPECTION
-
Visually inspect exterior of converter.
^
If severe damage is noted, such as dented, crushed or rusted out shell, replace converter.
-
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
-
Run the engine at 2,500 rpm for approximately 2 minutes to heat catalytic converter to operating temperature.
-
Connect a surface temperature probe on exhaust inlet of catalytic converter and measure temperature.
-
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.
-
If temperature differential is less than specified, catalytic converter should be replaced.
EXHAUST RESTRICTION CHECKS:
MANIFOLD VACUUM TEST
-
Connect vacuum gauge to manifold vacuum source.
-
Start engine and idle.
^
Note vacuum reading, and record.
-
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 75mm Hg (3" Hg), a restricted exhaust system is indicated.