Re: high hydrocarbon in exhaust

["ksgrimsr" <knut.s.grimsrud@xxxx>]

--- In dmcnews@xxxx, "tmpintnl" <tobyp@xxxx> wrote:
> Rendy - I don't believe that the catalytic converter would be 
involved 
> in high hydrocarbons.

<snip>

> Any other thoughts from the rest of you?


Since the car described has 30,000 miles on it and the O2 sensor has 
not been replaced, it sounds to me like it did not yet get it's 
scheduled 30,000 mile tuneup. I don't have my manual handy, but I 
seem to recall that the 30K tuneup includes O2 sensor replacement, 
cap/wires/plugs/rotor/etc, mixture adjustment, timing adjustment, as 
well as valve adjustment. If your car has not seen its regular 
scheduled maintenance yet, then you might consider having this done 
before starting to replace parts.

The catalytic converter should have a pretty long life -- I just ran 
my 150,000 mile DMC through DEQ here in Oregon and it passed fine 
with the original catalytic converter still on it. Premature 
catalytic converter failure (and O2 sensor failure as well) can be 
caused by catalyst contamination sometimes triggered by the use of 
leaded fuel (lead is only one of several effective catalyst 
contaminants). I've also seen catalytic converters that have failed 
mechanically where the honeycomb catalyst has broken up and in the 
form of rubble in the housing (this also generally resists exhaust 
flow).

Fortunately, the problem you describe sounds like a run-o-the-mill 
tuneup issue, and it sounds like your car might be due for one anyway.

Knut