Will
At 05:09 PM 3/20/03 -0800, you wrote:
> I'm leaning towards blocked cat, but I've got to be reasonably sure.
Some tests to check and inspect the cat:
1. This test can determine if the substrate in the cat has been
damaged and is broken. Using a rubber mallet (or something
similar), hit the inlet and the outlet pipes of the converter. If
there is a rattling sound then the substrate is broken. If broken,
substrate pieces can block flow and increase back pressure
thus causing engine performance problems.
2. Test the temperature with a pyrometer or something similar.
When the cat is operating correctly, the inlet temp. is lower
than the outlet temp. With the engine at normal operating
temp., measure temp. of the inlet pipe and then at the outlet
pipe. The outlet pipe temp. should be at least 100F higher
than the inlet pipe temp. if the cat is working properly.
3. Check the backpressure directly. Remove the O2 sensor
in the exhaust manifold and take a pressure reading using
the threaded port of the sensor. Generally, if the pressure
reading at idle is more than 1.25 psi of greater than 3 psi
at 2000 rpm, there is a restriction.
I know that some of the tests require special measuring tools but
HTH.
If any of the above tests indicate that the cat may be plugged, remove
or cut the converter from the exhaust system so you can make the
long drive to a garage. Shine a flashlight into the cat's inlet and
outlet pipes. A meltdown or breakup of the substrate will be visible.
If the cuts is down with some care and the cat does not prove to
be plugged, the cat can be put back on at a shop.
Bob Tom Burlington, Ont., Canada
'97 Dakota Sport, 4x2, CC, Flame red, 5.2L, 44RE auto., 4.56SG
This archive was generated by hypermail 2b29 : Fri Feb 06 2004 - 11:46:01 EST