Hi all,

I just bought 93 Sundance with about 150K 2..2 L and it failed test it
had high HC and CO output and it passed the Nox portion of test.
I have a 51 code O2 sensor stuck on lean .
The tailpipe insides are very black (unburned fuel?) hers what i
found so far

Car was sitting for about 6 months before I bought it. I went right
over to test lane has to pass in Indiana to get plates even. with gas
that was in for ???long
Failed test went home checked out found a vacumm line broke near PCV
valve repaired the tee fitting. Also found what appeared to be the
ground wire (the one that attaches to the head) to the O2 sensor
broke. I am thinking this may all that is wrong so how do i dtermine
if it is working again or do I have to reset something?
I read on the other posts that the too lean could just be the 02
sensor doing it job and I have another problem somewhere else I didnt
have plugs out yet but nothing looks really old.
Car seems to idle smooth and revs up fine at idle but when I drive it
it almost sounds like it missing or sputtering under load or
acceleration.You don't feel it only hear it
indoana one of those states wher if you spend $450 at an "approved
shop" they might issue you a waiver i didn't
Thanks For any input

Bill

unplug your o2 sensor see if that make a difference
you stated wire broke tho..other thing it could be is egr valve...


--
Scrapper


http://www.automotiveforums.com

<tonerdot (AT) yahoo (DOT) com> wrote

The high HC and CO indicate the vehicle is running rich. The code 51
indicates an O2 sensor that reads lean. The computer sees the lean O2
reading and adds fuel to richen up the fuel mixture. Replace the O2 sensor,
it's bad.



There is no ground wire on that O2 sensor. That should be a single wire
O2 sensor and the wire should run from the sensor to the computer. If the
wire is broken why not try and solder it back together and see if the O2
sensors works properly. It may be just as easy, in the long run, to just
replace the O2 sensor.


I am thinking this may all that is wrong so how do i dtermine

The easiest way to check it is with a scan tool. If you do not have a scan
tool see below.

You can check the O2 sensor for proper operation with a volt meter. The
engine will need to be at operating temp. Connect the positive probe from
the meter to the O2 sensor wire. DO NOT disconnect the O2 sensor wire, back
probe it at the connecter. Connect the positive from from the meter to a
good ground, the negative battery post works just fine. On a properly
working O2 sensor the voltage will fluctuate from around .2 volts to .9
volts. As long as the voltage is in that range and switching between high
and low it is working properly.

"Scrapper" <Scrapper.2omfzr (AT) no-mx (DOT) nodomain.com> wrote


It couldn't be the EGR valve, he said it passed the Nox portion of the
test.