On Mon, 13 Oct 2003, Higginbotham, David A. wrote:

> Oh no, this sounds like something I could really screw up, another guy
> mentioned that I need to be careful not to strip out the threads. This
> suggests to me that it might be easy to screw that up. I will have to be
> careful.
>
> Let me make sure I understand this correctly. If I just unplug the wire
> from the sensor and plug it into the new one without removing the old
> one or installing the new one that I can test to see if the engine will
> start when it's warm? I wonder if the parts guy will take the part back
> if it's not the sensor :)

This is an aircooled van, right?

You can do a quick test when the engine won't start by unplugging the
sensor wire and connecting it to ground through something with a little
bit of resistance, like a test light.  The engine should start right up if
the sensor is bad.  You can also test the sensor with an ohmmeter.

This sensor tells the engine computer how warm the engine is, so it can
enrich the mixture when the engine is cold.  If the sensor fails open, the
engine computer will run the engine too rich and it will flood.  If it
fails shorted, the engine computer will run the engine too lean and cold
starts will be difficult.  It's a cheap part, by the way, something like
$20 if I remember right.

Don't let my comment about stripping the threads scare you, just remember
that the head is soft aluminum.  The sensor should be snug enough that it
won't vibrate loose, but no more.  There's absolutely no need to crank
down on it.

David Brodbeck, N8SRE
'82 Diesel Westfalia
'94 Honda Civic Si