Date:         Sat, 2 Sep 2000 08:49:42 EDT
Reply-To:     kenneth d lewis <kdlewis@JUNO.COM>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         kenneth d lewis <kdlewis@JUNO.COM>
Subject:      Re: testing temp 2 sensor?
Comments: To: wdavidson@THEGRID.NET

Bill;
        This graph created a considerable amount of watch winding and
head scratching for me too. The second half of the graph is actually a
continuation of the first half but in an expanded view.  If you look
carefully the two graphs are numerically continuous. Use the left hand
ohm values for the left graph and the right hand values for the right
graph. You will see where the curve crosses the 50ºC line from the left
the resistance is about 800+/-100 ohms. Notice also  the resistance is
about the same crossing the 50ºC line into the graph on the right using
the values on the right. It is a lot easier to read the graph on the
right at these lower values.
        If you are going to ohm out the sensors I recommend you  only use
a digital meter. A quick and easy check is to compare the resistances of
the TEMPII and TEMPI sensors after the bus has sat overnite so their
temperatures equalize. Their values should be nearly equal. It IS
possible to pass this test and there still be a problem at other
temperatures.
        Our 85 ran fine during warm weather but when really cold temps
arrived it would not start. The TEMPII sensor was reporting a warm engine
hence the ECU was leaning out the mixture.
        To be absolutely sure, purchase a new one and test it at
freezing, room temp and boiling temperatures. A spare is also a good
idea. Our 85 is on her third TEMPII sensor.

Drive Safely & Good Luck
Ken Lewis    <Kernersville,NC>
86 VW crewcab;60 356B Coupe
--------------------------------------------------

On Sat, 2 Sep 2000 02:20:25 -0700 Bill Davidson <wdavidson@THEGRID.NET>
writes:
>On page 24.45 the Bentley shows a graph that plots ohms vs
>temperature...
>
>I've been assuming that the left side of the graph is for the temp 1
>sensor
>and that the right side of the graph is for the temp 2 sensor....
>
>But it does occur to me that at 50 deg C (the dividing line between
>left and
>right sides of the graph) the sensor(s) could conceivably have a
>discontinuous relationship between ohms and temperature, i.e.: both
>sides of
>the graph would apply to both sensors??? So which is it?
>
>Thanks,
>Bill

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