Hi,
First a working O2 sensor improves performance because it works. It is the
faulty ones that cause the problems.
You are incorrect regarding the rear sensor operation. Why would there be
two upstream sensors fitted if they weren’t there to equalize the other two.
The first two are the baseline readers. They sniff the exhaust directly out
of the motor.
The two after the cats sniff the exhaust after it exits the cats. With this
info the ECU then adjusts the mixture based on the readings of the O2’s.
There is something at work here called the stoichiometric ratio, which is
the ideal mixture of 14.7:1 air to fuel (by weight) for gasoline.
This is where the O2 readings come into play. Without proper readings from
the sensors, the ECU can’t get as close to that ratio as possible, and your
car runs RICH or it runs LEAN (bad for XJR’s)
Wrong on the price. I got 4 sensors for my XJR which are identical to XJ6
sensors for 100 USD a piece. Don’t forget that by replacing O2 sensors you
are not just saving on gas consumption you are also saving on cylinder wear
and oil changes as a rich mixture washes the oil off the cylinder walls, and
if you do oil analysis a better running car allows extended oil drains. It
all adds up. Not to mention the time out of your day having to stop for gas
more, etc, etc.
It’s also not true that the O2 sensor should last the life of the car. Why
are there vehicles out there that turn on the check engine light just
because the car has gone 50,000 miles?
Also the signal from the O2 sensors is measured in volts. I’m not sure if
most of you know but the oxygen sensors equipped in our X300’s are not run
of the mill O2’s They are used in only 2 percent of the cars made that use
oxygen sensors. They are of the resistive variety, and use a titania (not my
word) element rather than a zirconia element. You mentioned platinum, but
this precious metal was mostly used in CATALYTIC CONVERTERS, hence their
expensive nature as well.
In the last paragraph you mention “So I find hardly to believe that changing
working o2 sensor to another working sensor will improve something.”
I don’t understand why someone would switch out working sensors for working
sensors and expect an improvement. I will say in confidence that a car with
over 50 to 70 thousand miles is due for O2 sensor replacement. Regardless if
the dash Check Engine light comes on. Most of us here change out our spark
plugs at scheduled intervals, correct? Why should the O2 sensor be any
different?
Tim
1995 XJR> From: “AGIMELMAN” agimelman@HoTMaiL.com
Date: Wed, 3 Mar 2004 00:08:32 +0100
To: x300@jag-lovers.org
Subject: Re: [x300] X300 - Oxygen Sensors
In reply to a message from Timothy M. Sheehan sent Tue 2 Mar 2004:
Hello all,
I was dealing with o2 sensors for a last 2 years and I have no clue
how working o2 sensor can improve performance and solve problem
with gas consumption.
First - in US models only rear sensors responsible for fuel
cocktail.
So there is no reason to even touch front sensors.
Second - each sensor cost 125 - so for 2 of them minimum that you
will pay it’s 250. For 250 you drive and drive and drive until you
will get balance.
Third - the reason why is o2 sensors so expensive that they are
made from platinum or may be made of different expensive metals
only to last for a long time - o2 sensor should last for a life of
your car easy. May be Jaguar sensors were badly design and that is
reason why your sensors can fail. But failure may happen not only
to sensor but also to heater part - because modern sensors are
heated - that is why they have 4 wires.
And sensor sends signal to ECU - signal in ohm - I don’t remember
digits but it doesn’t matter. Its sends signal depends of how reach
is your mixture in exhaust and ECU corrects how much oxygen or gas
to send by injectors. So I find hardly to believe that changing
working o2 sensor to another working sensor will improve something.
Get obd2 reader - plug it in and drive and see how your o2 sensor
reacts to the acceleration.
Of course you can check o2 sensor and see they may be dirty and you
can try gently to clean them up but you should not feel difference
in driving.
That is just my opinion from my experience.
I may be wrong - correct me then
–
Alex
Lake Bluff, United States
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–