Bad o2 sensor or cat

According to the blinking light my 96 Integra its telling me the cat is
operating below efficiency. Here in the great state of PA we need
emissions tests every year and next month is time for mine. Is there a
way to tell if the o2 sensors are bad or a new cat is really needed? I
don't feel like paying for a new cat.

O2 sensors output a voltage that the computer reads, correct? I wonder
if the voltage starts to drop off it will say the sensor is bad. Maybe
make a voltage divider to fool the computer?


Adam

Adam Stouffer <adam_stouffer.TakeThisOut@hotmail.com> wrote in
news:CdX4f.5757$hx.1122@trndny08:

> According to the blinking light my 96 Integra its telling me the cat is
> operating below efficiency. Here in the great state of PA we need
> emissions tests every year and next month is time for mine. Is there a
> way to tell if the o2 sensors are bad or a new cat is really needed? I
> don't feel like paying for a new cat.



This error shows up mostly on cars that are primarily city-driven.

Take the car out to the highway for a good, hard, hour's run. Longer if you
can. Highest speed you can get away with (legally of course...). Turn on
headlights, A/C, rear window defroster, also open all the windows, anything
to increase load on the engine. You want to heat up the cat good and hot to
help it burn off the contaminants.

Problem might go away, believe it or not.

If PA's smog just plugs the car in instead of subjecting it to a dyno,
you'll need to wait at least three ignition on/off drive cycles for the
ECM's memory to clear. Then book a new smog check.

You also might want to check the car's original purchase date. The
Federally-mandated eight-year cat warranty is measured from that.




>
> O2 sensors output a voltage that the computer reads, correct? I wonder
> if the voltage starts to drop off it will say the sensor is bad. Maybe
> make a voltage divider to fool the computer?
>


Not quite. The secondary sensor is supposed to flatline at reference
voltage (about .45V). If it starts flip-flopping like the primary sensor,
the efficiency code will eventually be set.

Your ECM conducts regular 5-minute checks on secondary sensor operation. If
it gets three failures in a row, it will also set a code.

--
TeGGeR®

The Unofficial Honda/Acura FAQ
www.tegger.com/hondafaq/