[T3] Car Runs Great, but Why?

[Phil Hof]

A little knowledge can sound right, but not quite be right.  Your mechanic
is not too far off with his advice, but a little more info might let you
understand it better.

As posted it is often fine to leave the intake air temp sensor unplugged.
It is merely a tertiary mixture adjustment (primary being manifold vacuum,
secondary being head temp).  However, it is still important that the jet not
leak; even unplugged, it is under pressure, and a leaky jet can richen your
mixture and even force gas into your oil after shutdown, same as a regular
injector.  Either verify it does not leak by removing it and observing it
under pressure, or cap off the line ahead of the jet.

They usually open, not short, which would look the same as an unplugged
sensor to the ECU.

The temperature profile is in these graphs (TS#1 is intake air):
http://images.thesamba.com/vw/gallery/pix/338293.gif
http://images.thesamba.com/vw/gallery/pix/759265.jpg

The first is from Bentley, the second from the VW Workshop Manual.  One
gives the min-max ranges, the other the nominal values over a wider range;
either will work well enough.

Replacement sensors are available on the Samba and ebay regularly, either
alone or as part of a set of parts by an impatient Type 3 owner. ;-)

-Phil

---------------------------------------------------------
> From: "J. Jonik" <j_jonik at yahoo.com>
>
> OK ?? I just Called that mechanic.? He said that the head temp sensor is
doing
> the work and not to worry about the Intake temp sensor being unattached.?
He said
> that there would not be excessive fuel consumption. ?? He said the sensor
(and
> the other two I tried) was probably Shorted Out, and that it will be hard
to find
> a replacement anyway.
> ? Or, does someone here have a certifiably non-shorted-out Intake Sensor
around
>  the shop?
> ? And, apparently there's no need to plug the nozzle on the un-used Cold
Start
> Switch. I guess, with the wires unplugged, nothing tells the sensor to
pull in
> a gas spray....or air.
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