Re: 1985 E28 Oxygen Sensor

["Ron Buchalski" <rbuchals@xxxxxxxxxxx>]

The O2 sensor measures oxygen content of the post-catalytic converter gases, 
and sends an indication to the engine computer to make the fuel mixture rich 
or lean.  It's a closed-loop control system.

If your O2 sensor is disconnected, there is no feedback mechanism, so you're 
running in an open-loop mode.  The engine computer may end up running the 
engine on a mixture that's too rich.  This can result in overloading the 
catalytic converter, causing it to overheat and melt (the internal 
catalyst), possibly forming a big slug that'll partially block your exhaust 
path.  A blocked exhaust system is a BAD thing.

With O2 sensors costing $50-115 (depending on the type), it's alot cheaper 
than a catalytic converter, and it's easier to replace, too!  If it wasn't 
necessary, it wouldn't have been part of the engine management system.

- -rb



>
>Date: Wed, 08 May 2002 12:52:42 -0400
>From: ROSSVIIIV@domain.elided
>Subject: 1985 E28 Oxygen Sensor
>
>How critical is the oxygen sensor on this model 535iA to the long 
>reliability and performance of the engine & exhaust system?
>
>I've owned the car from new and I've been running with it disconnected for 
>years with no noticeable ill effects.  The most apparent is a slightly rich 
>exhaust smell, occasionally.
>
>I've bought a new one, but hesitate to install it, unless it's really 
>necessary.
>
>Comments?
>P. Ross
>rossviiiv@domain.elided (direct)
>


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