Oxygen Sensor for 5KTQ

SJ syljay at optonline.net
Fri May 6 14:33:37 EDT 2005

A note on oxygen sensors.
I read someplace that oxygen sensors need a fresh air supply to one
side(inside) of the sensor in order to generate a sensor voltage . . .
atmospheric oxygen on one side and combusted gases on the other side.

I assume that the aftermarket sensors which have the short leads have the
fresh air intake built into the hardware someplace -- prone to clogging ?
But some sensors, especially the ones with long wires and connector, use the
wire insulation as a conduit for fresh air(oxygen). The oxygen supply to the
inside of the sensor is via capilliary action in the wires. The wire ends at
the connector(clean protected environment) are open to the atmosphere.

You could run into a problem if you:
1. use a known good audi sensor(with attached connector)
2. replace the one in your car
3. you are too lazy to fish the wire and connector thru
4. you cut and splice the wires

You have just cut the conduit for the fresh air supply.
Depending on how its spliced and sealed, maybe this wont affect the air
supply to the sensor. Then again, maybe it will.

I dont think the O2 sensor needs much oxygen on the inside . .. just enough
to replenish the small amount  used during oxygenation of the inside metal
and parts due to age and heat.
If the conduit is sealed, the sensor will work ok in the beginning. But over
time, the sensor voltage will become lower  as the oxygen difference between
the outside and inside of the sensor body becomes reduced.

Thats my theory. Any comments?

85 Dodge PU, D-250, 318, auto
85 Audi 4k - - sold but still on the road
88 Audi 5kq
90 Audi 100q

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