[T3] My final question on IAD's

William Jahn willjahn975 at gmail.com
Tue Jul 18 10:54:24 PDT 2023

I have the back cover off , the one with the PCV pipe. I looked at both
ports, to the trans modulator and both are after the throttle plate. Both
ports are also 5/16" OD but inside the ID is very small , small enough only
a small wire , can't get a pipe cleaner through them. I have mine Teed
together the one facing down at the throttle end and the one facing out
with the runner pipe RT side . I didn't go over the top in the runner pipe
for 1&2 mine both run down long hose on the front one  the tee is a few
inches back from #1 runner pipe.

 Tram one of the Samba members is sending me one which has only one
modulator pipe next to the AAR fitting. I imagine one will work since
earlier models like 71 only had one minus the PCV pipe. I have a 72 model
year on the car now the only difference between it and the 73 , no EGR pipe
,it's blank there, the extra vacuum port the the dual port vacuum can , it
does have the PCV pipe on the back cover. It seems only late 72 and all 73
have the PCV pipe, well at least CA built cars , as far as I know the EGR
was only used on 73 CA built cars.

On Tue, Jul 18, 2023 at 9:49 AM Jim Adney <jadney at vwtype3.org> wrote:

> On 17 Jul 2023 at 14:32, William Jahn wrote:
> > I was curious why there are two ports tee'd together on 72 and 73 fuel
> > injected Auto trans models which seem to be California built cars. The
> is a
> > CA built and Federal . I looked at mine and both ports are after the
> > throttle  plate.
> >
> >  Do I need two for the trans to shift? Or will one do? I cannot find any
> > info on this.
> I don't know. Mine is the same and it's always bothered me, too. I THOUGHT
> one of the ports was in front of the throttle plate, at least at idle, but
> I haven't
> spent any time studying it. I've never seen any info on this.
> I've always wondered if there was an orifice somewhere in the conductance
> between those two ports, but I've never taken anything apart.
> On mine, one of the hoses wraps over the top of the #2 air runner, and
> time
> has crushed the hose flat there. I've wondered if this means that that
> hose is
> no longer working. Everything still works, except that the 2nd to 3rd
> shifts
> tend to slip unless I'm accelerating hard. No problem with 1st to 2nd or
> on
> any downshifts.
> --
> *******************************
> Jim Adney, jadney at vwtype3.org
> Madison, Wisconsin, USA
> *******************************
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