From: Rastamon on
I recently had to get a SMOG test for my 86' 22R PU. It barely failed CO,
by 0.08, from the maximum allowed. Everything else was within normal limits
if not below. I don't use this PU that much, it's my HomeDepot beater. The
last oil change was 6 months ago. I've already replaced the air filter and
the plugs and wires are about 6 months old.

Can just doing an oil change get me below the maximum CO level?


From: Charly Coughran on
"Rastamon" <rasta(a)dakine.com.invalid> wrote in
news:00098c64$0$2373$c3e8da3(a)news.astraweb.com:

> I recently had to get a SMOG test for my 86' 22R PU. It barely
> failed CO, by 0.08, from the maximum allowed. Everything else was
> within normal limits if not below. I don't use this PU that much,
> it's my HomeDepot beater. The last oil change was 6 months ago.
> I've already replaced the air filter and the plugs and wires are
> about 6 months old.
>
> Can just doing an oil change get me below the maximum CO level?

No, an oil change wont help. CO is produced by incomplete oxidation of
the hydrocarbons in the fuel mixture. If the oxidation was complete
there would only be CO2 in the exhaust. So to reduce CO levels, you
might want to tune the engine up. Did you tune it when you changed the
plugs and wires? The new air filter might help a little if the old one
was limiting air flow; you might try leaving it out for the test if you
can get away with that.

The catalytic converter also lowers CO levels by transforming CO to CO2,
but catalytic converters aren't cheap.


--
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Charly Coughran
ccoughran(a)DELETE-TO-RESPOND-UCSD.EDU
From: al on
On Aug 20, 4:37 pm, "Rastamon" <ra...(a)dakine.com.invalid> wrote:
> I recently had to get a SMOG test for my 86' 22R PU.  It barely failed CO,
> by 0.08, from the maximum allowed.  Everything else was within normal limits
> if not below.  I don't use this PU that much, it's my HomeDepot beater.  The
> last oil change was 6 months ago.  I've already replaced the air filter and
> the plugs and wires are about 6 months old.
>
> Can just doing an oil change get me below the maximum CO level?

High CO means it is running too rich. Did the old plugs look carbon
fouled? Many things can cause it to run rich. Is it running too
cool, is the carburator choke sticking closed? Those are the first
things to eliminate. Good luck. Al