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From digest.v4.n666 Fri May 31 19:36:49 1996
From: Dana Baum <>
Date: Fri, 31 May 1996 15:46:15 -0700
Subject: Cheap O2 Sensors

A couple of things to remember when replacing the O2 sensor with an Ersatz part, does it have the same number and position of slots at the sensor tip? Does it have flaps to the left or right in the tip shield? Is the protruding tip the same length?

The position of the O2 sensor in the exhaust flow determines the quality of the sampling and the response timing of the feedback loop. The major difference in the sensors for the different cars is not just the cost but the response rate. Lower number of slots less gas sample generally slower rate. A cheap O2 sensor will work in a BMW but you will be buying a catalytic convertor before you know it. In a 1981 model the response is slow and the need for a quality sensor is not great. In a 1988 528, a cheap sensor can result in a totally bogus loop rate resulting in a rich idle and a fried convertor. The cost of most Bosch O2 sensors is in the range of $60-$80. Multiply by 2 for dealer price to you.

Cross matching the same part for price is fine, but make sure it is the same part. In some cases close won't do. To be penny wise and pound foolish with a fine piece of engineering will result in an imposition of Murphy's Laws.


     ("`-/")_.-'"``-._                   Dana Baum
      . . `; -._    )-;-,_`)
     (v_,)'  _  )`-.\  ``-'     San Farancisco California USA
    _.- _..-_/ / ((.'
  ((,.-'   ((,/    

"I can't wait for immediate gratification."

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