At 11:53 4/7/99 -0500, Jodi Sage wrote:
>Replacement.   HOT DOG! Mystery solved that hangy down thing and the magazine
>drawing look alike!  It's my O2 sensor.

<snerk>

>at cylinder #1.    They also told me that the CO2 setting cannot be adjusted
>because the CO2 check valve is gone, due to previous exhaust work.   (Instead
>of replacing the entire exhaust I had new pipe sections cut and spliced onto

It's CO, not CO2 -- there's no check valve, but there (used to be) a little
pipe fitting sticking out of the pipe ahead of the catalyst, with a cap
screwed on it.  They unscrew the cap and stick the CO probe into the hole.

>the old. ) The exhaust just  started to roar last Sunday when I was coming
>back from a week in Detroit (I live in Iowa).

That would be the O2 sensor.  Examine the *top* of the pipe ahead of the
convertor, and you should find a threaded hole that the sensor screws into.
 They don't usually fall out, though, generally it's the other problem.

>What is the CO2 check valve?  Am I causing any future severe engine problems
>by not having one?

See above.  You can't set the idle mixture.  Between you and the
authorities how much of a problem that is.

>How is it associated with the O2 sensor?

Not.

>Is the location of the O2 sensor near or at cylinder #1?

See above (that way I don't have to admit I forget which is cylinder 1 <g>).

>Would the O2 sensor have been removed to do any tune up work?

No.

>The sensor looks really old, yet the dealership didn't or hasn't changed it,
>since it's loose would it be a good time to change it and can I change it
>myself?

On an '85 'sposed to be changed every 30k miles, I think -- maybe every
60k.  There's a light on the dash that comes on.  You reset the light by
looking under the left front wheel for a square box inserted into the
speedo cable -- there's a shielded pushbutton on the box.  Push it until
the light goes out, may take a couple tries.  I think it clicks...

Putting in a sensor is just 1) getting it 2) splicing the wire with a good
waterproof connection 3) screw it in and tighten.  You can test the
existing one by installing it, running the motor up to temp, then measuring
voltage btw the sensor terminal and ground, should be wavering around half
a volt.  If it's good, no need to mess with it.

>Could the dislodged sensor be causing the exhaust roar?

You bet.

david
David Beierl - dbeierl@ibm.net