[T3] 73 auto trans type 3 ARR ?

[William Jahn]

 Yes the EGR was junk long ago, I made a steel plate to fit the right heat
exhanger and used the same gasket you did to block it off. I used the IAD
off the 72 I had in place of the 73 IAD , same thing just in better shape
and no EGR pipe to deal with.

 When I replaced the runner short hoses and intake gaskets I removed the
cover and idle adjust and completely cleaned the entire inside and outside
and all the internal vacuum pathways including the Idle screw internal
paths or bores.  While I had the IAD cover off I cleaned that pipe
internal. I made a new gasket for the cold start valve and secured the two
screws well .  I replaced all the vacuum lines including the two from the
IAD to the trans modulator and used a new vacuum T that connect the two
lines from the IAD that merge into one for the modulator. Thought I'd check
that vacuum T just in case to see if it has not cracked. I removed the PCV
and cleaned it as well just to remove the old dry muck. I replaced that
hose as well from the PCV to the IAD.

 I never liked the idea of spraying carb cleaner around a warm engine for
two reasons, 1 possible fire,2 it kills rubber hose and dries it out . I
never tried propane. heard of smoke testing . I never found a vacuum leak
by these methods, I always just checked the fittings and the hose for
integrity. My first plan is to check the vacuum T to the modulator and the
hose from the AAR to the IAD just to rule out. Then all the vacuum lines
and their fit at the fittings. If I find nothing there I'll check the
distributor to see if for any reason the advance weights hang up . I know
one can see the springs with the breaker  plate in place but not the
weights.

 You are right that the mechanical advance from idle to 1400 will change. I
do know a few years back the timing was not returning to 5 degrees it would
hang. I had the 72 AJ dist in it and once I removed it I found the weights
and everything was rusty. I never opened it up to look before. Before this
happened I cleaned out the AH dist and checked everything and it needed a
good cleaning and new fiber washers . It had no wear so I lubed the
bushings and all the pivot points used oil and bosch dist grease and also
cleaned and lubed the breaker plate and ball. I wanted a good clean dist
just in case and the proper model year for my engine even though the AJ
worked fine.

 What makes the most sense to me at this point is something dist related
causing the advance to hang . It runs fine and doesn't ping but I suspect a
weight hanging or binding causing it not to return to 5 DBTC and if so we
know the RPM will rise. I do have another 73 dist but for a manual trans
that I took apart and cleaned and lubed and replaced the fiber washers and
set the end play that I can install  in case there exists an issue with the
AH . It will get me by until I can check the AH well. The only issue with
the 73 AG manual trans one is the longer weight pin has a bit of a groove
but it's not too bad so it should work for the time being. I wouldn't need
to if I had another car to drive but this is what I need to do.

 I hope I can look into this today. So far I do know whatever the issue
that causes this, it is not destroying the engine or trans. it's not over
advancing as a broken advance weight spring would cause. It's just better
to have it return to the proper idle speed and be repeatable.

 William

On Sat, Jun 10, 2023 at 11:23 PM <jadney at vwtype3.org> wrote:

> On 10 Jun 2023 at 16:46, William Jahn wrote:
>
> >  I got new Intake gaskets from you Jim. I did this work at the end of
> 2019
> > . I cleaned everything and even sealed the IAD back cover gasket using
> > silicone on both sides. Let it set up the 4 bolts loose then when dry
> > tightened them. I replaced every vacuum hose  and the injector seals and
> > all the fuel line . I made certain the IAD lined up perfectly with the
> > runners , and had to bend 2 slightly.
>
> Okay, sounds like you've got all those things covered.
>
> Have you checked the tightness of the two screws for the cold start valve?
>
> How about the hoses for the AT vacuum modulator?
>
> Does your engine still have the EGR valve and plumbing? If so, have you
> blocked it off?
> Checked the short hose that connects the 2-piece pipe to the IAD? (I made
> a blockoff plate
> for the flange to the EGR valve inlet and sealed it with one of those tiny
> VW metal manifold
> warmup gaskets. The heat exchanger also got a blockoff plate and gasket.
> My EGR filter fell
> apart and has been completely removed.)
>
> You could try flushing out the idle air channel with something like WD-40.
> And check the
> '72-3 crankcase breather that vents into the IAD cover; could there be
> something intermittent
> there? (Flush the breather port in the cover and the PCV valve in the
> breather box with
> WD-40 to make sure they're not clogged with gooey oil.)
>
> Keith's suggestion of looking for a leak with an unlit propane torch is
> always something to
> consider, but I've always found this to be hard to interpret. Maybe I've
> just never come across
> a large enough leak.
>
> If all those seem okay, yeah, maybe there's a problem with the
> distributor. You should be
> able to see if the timing always comes back to the same point at idle with
> a timing light, but,
> again, that's hard to interpret, since the timing SHOULD change between
> 800 and 1400
> RPM. Maybe you can just watch how it moves as you move the throttle and
> RPMs up and
> down.
>
> --
> *******************************
> Jim Adney, jadney at vwtype3.org
> Madison, Wisconsin, USA
> *******************************
>
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