Re: Catalytic Converter

[Elliott Potter <epotter@abraxis.com>]

>
>What would cause a catalytic converter to break up?  I thought these
>things lasted forever, unless the car isn't running properly.  My mom's
>1984 5K, with 64K has the distinct clatter of platinum moving around in
>the cc shell.  What things should I check for?  Do I need a mechanic
>with a machine to check codes to see if it is running properly?  She
>does only drive this car less than 1 mile each way, to and from work.
>
Have you looked down there yet?  If she doesn't drive for long extended
trips, it's very possible that a piece of it has rusted loose and the
whole thing is moving.  That's really the best thing that could be
happening, seeing as how expensive catalytic converters are...


Symptoms of a faulty catalytic converter are:
-Poor power output
-Idle speed drops
-Engine stalls
-Rattle in the exhaust (uh-oh)

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 (cc) 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
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 degrees F (38 degrees C) hotter than
inlet.
[note this number is for the V6; someone want to say if it's different
on the I5?][or I4, or whatever it is?]
4. If temperature differential is less than specified, catalytic
converter should be replaced.

DROP TEST (eek!)
1. Remove converter from the car.
 a. Hold the converter vertically and drop it from about 20cm (8in) onto
a block of wood.
 b. Turn the converter over and drop it on its other flange from the
same distance.
 c. If a slight knocking sound is heard from inside the converter, or if
the ceramic grid moves inside the housing, the converter is damaged and
should be replaced.


There's another testing method that involves a back pressure sensor.  If
you have one, I can post those instructions.

HTH!

Elliott