[Shotimes] Oxygen Sensor Question

[Mike]

Our 3-way cats also reduce NOx.  Usually the HC also will be high, maybe
just low enough to pass, if the cats are weak.  When the engine is cold and
off, take a piece of vac hose and suck on the EGR valve.  If its working
properly you can hear/feel the valve open and close with a little suction.
If you haven't changed the tube coming from the manifold its likely burned
through, although you may not be able to see it with the braid covering it.
I've heard of excess carbon on the pistons also causing high combustion
chamber temps, although no personal experience.
Mike

----- Original Message ----- 
From: "George Fourchy" <krazgeo@comcast.net>
To: <shotimes@autox.team.net>
Sent: Monday, April 12, 2004 10:17 PM
Subject: [Shotimes] Oxygen Sensor Question


> OK....our cars out here don't last forever.....they just last longer.
>
> One of the SHOs that was ini my fleet a year or two ago, and now belongs
to someone
> else, won't pass emissions....it puts out about twice as much NOx as is
allowed.
> Other than that, it runs fine.  It's a '91.
>
> Just for grins, we changed the oxygen sensors on it....got some Bosches
from NAPA.
> It didn't have any CE light issues before they went in, but now the KOEO
test says
> the two banks of cylinders alternately run lean.  This is the indication
problem
> those sensors cause, right?
>
> (I'm not a CE test procedure virgin anymore!!!)  ;-)
>
> What was the fix?  Seems like Autozone sold the proper sensors?  I can
take these
> back.
>
> I didn't keep those posts, because I didn't think I'd have this
problem.....shows
> you what _I_ know, huh!!??
>
> I'll run the test on the Lowrider tomorrow.  I'm thinking the EGR valve
has come
> apart on it, due to old age and sitting around for months, and it's
getting too much
> exhaust into the intake all the time.  That would explain the noise and
the power
> loss when it is warm.  I'll test THAT procedure tomorrow, too.
>
>
> George
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