[Vwdiesel] idle switch, diesel leak, oily engine block

[Scott Alexander]

On Fri, 2004-01-02 at 16:32, Mark LaPlante wrote:
[lots of stuff deleted about a fuel leak.  I have guesses, but just from
reading the book.  Someone with practical experience should field
those.]

> As for the idle switch, I found it had come loose in the engine 
> compartment. So, can someone tell me what is its normal orientation? 
> Also, what is its function? I hadn't noticed any running problems 
> (other than decreased mileage).

Assuming that you are talking about the electrical switch which sits on
top of the fuel pump, it should be pointed so that the accelerator
doohickie pushes it when the accelerator is not being pressed.  My
understanding, though, is that it is only used as part of the upshift
circuit.  It is there so that the light doesn't come on when you are
coasting down a hill with your foot off the accelerator.  As such, it
shouldn't affect the fuel economy.

(Near as I can tell, the only electrical bit involved with running the
engine in my '82 Rabbit is the stop solenoid and the circuitry for
turning on the fan.  There are, of course, various sensors like the
coolant sensor that is electrical, but I don't believe any of those
changes the operation of the system (except WRT the fan.  Having
recently picked up the Bosch/Bentley books on the VE fuel pumps that we
have in our Rabbits, I am amazed at the mechanical complexity and a bit
surprised that they didn't use a mechanical plunger operated by a cable
to shut off the fuel in keeping with the mechanical design. :)

Anyway, I'd look for the fuel leak as the source of your decreased
mileage and ignore the idle switch in that regard.

[snip]

Best,
Scott
-- 
Scott Alexander <salex at dsl.cis.upenn.edu>