what are these "archives" that you speak of?
it is friday right?
jason
90gl

>From: Frank Grunthaner <FrankGRUN@AOL.COM>
>Reply-To: FrankGRUN@AOL.COM
>To: vanagon@GERRY.VANAGON.COM
>Subject: Inexpensive O2 Sensors - A Suggestion
>Date: Thu, 15 Feb 2001 22:59:51 EST
>
>Just a few comments to the O2 sensor thread:
>
>1). All Bosch patent single wire O2 sensors are functionally identical to
>all
>other Bosch single wire sensors.
>
>2). All Bosch patent three wire O2 sensors are functionally identical to
>all
>other Bosch three wire sensors.
>
>3). All Bosch patent four wire O2 sensors are functionally identical to all
>other Bosch four wire sensors.
>
>4). Proviso: The catalytic ceramic sensing element could have a variety of
>different protective shields (including no shield) in place depending on
>part
>number and OEM design requirement.
>
>5). Nothing in the design of the element shield will significantly effect
>the
>operation of the O2 sensor in the in its Digifant or Motronic application.
>
>6). So buy the least expensive unit you can. The Ford universal is just
>fine!
>Bosch is a quality outfit of first order so the functionality of the
>inexpensive 13913 will be identical whether you buy it from Ron,
>PartsAmerica
>or your Ford dealer. Only the profit margin will vary.
>
>Howsomeever, it is totally unnecessary to hack off the end of the universal
>O2 sensor and splice on the VW connector. There is a better way! I've
>posted
>this in the archives. And I will leave the details to the archives to
>stimulate the many newbies (you know who you are) to check out this
>resource.
>
>Both crimping and soldering wires offer the possibility of repeated failure
>as a function of temperature if not done well. Doing it well (general
>statement) requires either a significant level of experience (well
>remembered
>glossary of stupid mistakes paid for in time and scar tissue) or a healthy
>dose of dumb luck!
>
>The longevity of the crimped connection is directly governed by the ability
>to mash two or more metals together to trigger surface flow and local
>welding. The quality of this connection depends on a metal to metal contact
>(that is, no room for oxidation)! With oxidation one quickly moves into
>interesting solid state research questions as to the nature of the charge
>carrier in the oxide (read insulator), the extent of a tunneling
>contribution, etc., etc., - all leading to bad experiences for ECU and the
>owner/operator.
>
>In the case of the soldered joint, elevated temperatures lead to possible
>liquefication of the solder, diffusion of the solder alloy into the primary
>conductor and oxidation. All bad. I could go on but in the interests of
>brevity let me go directly to the appropriate conclusion/lesson. Keep the
>solder junction or crimp junction as far away from the heat source as
>possible. The heat source for this dissertation is the O2 sensor (being
>heated by the exhaust gas). If you measure the temperature drop along the
>wires coming from the sensor, you will be surprised at how well
>multistranded
>wire conducts heat.
>
>However, a basic observation in thermal transfer mechanics is that it is
>nearly impossible to conduct heat across a modest pressure mechanical
>contact. To summarize, the biggest thermal drop is across the connector. So
>to paraphrase my missive in the archives (hint):
>
>7). Don't hack-off the connector on the 13913 universal sensor!!!
>
>8). Do go to your local recycling bistro (junkyard - you own a Vanagon
>remember!) and grab the end connector from a Ford product (see archives
>remember!). Cut it off with at least 6 inches of length (I use 25 cm. and
>always ask the yardman to verify the length. No sense of humor have those
>guys, I find).
>
>9). Now go to the VW side and cut off the line to the O2 sensor saving the
>connector to the harness and as much cable as you can stand. I believe the
>connector for the Golf/Jetta/etc. group is the same as for the waterboxer,
>but can't be sure since I don't really know what those things are. Check
>and
>verify. Believe more detail on this is in the archives.
>
>10). Go home.
>
>11). Check to see if wife is home. Wait for safe window of opportunity.
>Soldering and heat shrinking will take about 35 minutes.
>
>12). If wife is safely out of the house, spread out the soldering tools
>(don't like crimping - seems so brute force-ish, soldering seems so much
>more
>cerebral) wire cutters, strippers (wire), heat shrink tubing, matches - and
>the two cables on the dining room table. Of course, the Ford connector will
>plug into the O2 sensor connection, and the VW end will go into the
>harness.
>Stagger the wire lengths and have at it. Such details are well covered in
>the
>archives (redundant hint). Which wire goes where?? See the archives. I
>always
>use high temperature 3M heat shrink tubing and put tubing over each
>junction,
>then cover the bundle with another dose of heat shrink.
>
>13). If wife won't leave, spread out on the garage floor and proceed
>through
>step 12 appropriately.
>
>14). When done ladle some high temp antioxidant contact grease over the
>Ford
>sensor pins if its not already there. Then connect your adapter cable to
>the
>harness (you checked everything for continuity when you finished soldering
>-
>right?) then to the installed sensor and motor happily away.
>
>Sorry for the length, but I wanted to find a way to subtly work-in the word
>"archives".
>
>Frank Grunthaner

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