Michael Maskalans <mike-lists@tepidcola.com> wrote:
: On Saturday, August 9, 2003, at 09:57 AM, Bob Tom wrote:
:> While the O2 sensor does
:> not affect performance or operability, the code will cause the pcm to
:> stop
:> monitoring the EVAP and rear O2 sensor circuits so if other problems
:> in these areas crop up, you'll never know it. At least, that's my
:> understanding.
: I'm not so sure about the not affecting operability. although in my
: case I had a funky reading on a working o2 that the computer way paying
: attention to. I have no idea why, but when I was running around with
: my exhaust pipe (nearly) off, I was running *incredibly* rich - to the
: point that it could almost try to stall at idle.
: so, if the computer is getting a funky reading from an o2, you'll
: certainly get odd running conditions. However, if the computer
: actually knows there's something wrong with it, it probably will throw
: a code and then use a default value and assume things are 'okay'-ish.
Michael - when your exhaust came apart, it did affect the operation
because it was the front O2 sensor that was affected (this is the
sensor that is used to trim the fuel, the post-cat O2 sensor is
basically there just to monitor the health of the cat.) You were
running rich because having the exhaust wide open just after
the O2 sensor put a lot more oxygen in the area than usual, which
would cause the computer to assume you are running lean and try to
compensate with more fuel.
Regarding the original poster, if the heating element in the
upstream O2 sensor went out, it would probably still work Ok, would
just take a lot longer for the sensor to start spitting out reasonable
numbers. For the downstream sensor though, it probably will not get
hot enough back there to generate accurate readings. However, since
the rear O2 sensor is only monitoring the cat, the worst that will
happen is for your check engine light to come on, telling you that
the cat and/or the sensor should be checked out. You shouldn't notice
any actual operatability or performance differences.
---Jon-
.---- Jon Steiger ------ jon@dakota-truck.net or jon@jonsteiger.com ------. | I'm the: AOPA, DoD, EAA, NMA, NRA, SPA, USUA. Rec & UL Pilot - SEL | | 70 Cuda, 90 Dak 'vert, 92 Ram 4x4, 96 Dak, 96 Intruder 1400, 96 FireFly | `------------------------------------------ http://www.jonsteiger.com ----'
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