Re: [T3] adjusting throttle valve switch

["Jim Adney" <jadney@vwtype3.org>]

On 26 May 2008 at 0:58, David wrote:

> I have a '72 TVS that does not seem to have any stop built in, only the
> slots in the mounting bracket for the mounting screws. I can rotate the
> switch fully to the ends of these slots in either direction.
> Does this style TVS mean I need to use a Ohmmeter to adjust?
> If not, am I supposed to rotate the switch clockwise until it can't rotate
> anymore (end of slots) and use this as the starting point before rotating
> counterclockwise?

You probably have the Orig version, without the stop. Even if you 
have the stop you can adjust with the ohmmeter. The stop is inside 
the black plastic cover, so you can't tell the difference except by 
looking at the part number or looking inside.  

To adjust with the ohmmeter, check the bentley and find the 2 pins 
that lead to the idle (closed throttle) contacts. Connect your 
ohmmeter between those pin numbers. The numbers are molded into the 
black plastic.  

Rotate the housing CW and CCW, noting that the ohmmeter changes at 
some point. Once you find that point, turn the TVS CCW until the 
ohmmeter changes, then continue CCW half an index mark on the TVS 
baseplate. Tighten the screws.  

Check the adjustment by noting that the ohmmeter changes as soon as 
you start to open the throttle.   

The key is that the idle contacts should be in one state with the 
throttle closed and in a different state any other time.  

-- 
*******************************
Jim Adney, jadney@vwtype3.org
Madison, Wisconsin, USA
*******************************

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