[T3] : Re: 73 Type 3 Ignition Switch

William Jahn willjahn975 at gmail.com
Thu Oct 22 01:01:54 PDT 2020

Maybe I'm wrong here. The primer switch runs the pump key off and so gets
all the air or most of it out of the fuel ring , meaning from both the
pressure side and return. The 72 and 73 have a TVS or TPS that with the key
on you hear 20 clicks which I thought basically overrides the dist
position. Once running the dist will fire two pairs at a time. I thought
the basic enrichment when you accelerate was done via the switch as well as
decell when the switch cuts off the fuel via the two position micro switch
which determines the circuit board zipper and also brings in the WOT at
about 3/4 travel. The 72 and 73 have a 5 pin switch and the Pressure sensor
with one adjustment  has no WOT enrichment like the earlier 71 and 70 have
and even the 68 & 69 which has the vacuum controlled switch.  It seems if
you are at a steady speed the TPS is in a position for the zipper contacts
are engaged by the micro switch  and the dist then fires two pairs  until
you let off the throttle then you get no fuel from the injectors.

 I'm probably not explaining it very well.

On Wed, Oct 21, 2020 at 5:54 PM Jim Adney <jadney at vwtype3.org> wrote:

> On 21 Oct 2020 at 11:24, Gary Forsmo wrote:
> > So .....
> > By pumping the accelerator pedal, once or twice, while activating the
> Fuel
> > Pump with the (Adney- installed) Remote Fuel Pump Switch,
> > ..... does electricity also acivate ALL of the Fuel Injector Pintils
> > simultaneously to clear out the air from ALL of the fuel injector "stub"
> > hoses ?
> It only applies to the pair of injectors which happen to be "enabled" by
> the positon of the
> distributor at this time. One pair is generally sufficient to make
> starting easy.
> > Is this unique to '73's?  Or does it affect all fuel injected model
> years?
> It applies to all '70-73 models. The TVS (Throttle Valve Switch) on
> earlier years did not
> include this function.
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