[T3] Irregular Idling...again...Update
Jim Adney
jadney at vwtype3.org
Tue Nov 13 19:43:39 PST 2012
On 13 Nov 2012 at 21:38, Jim Adney wrote:
> On 13 Nov 2012 at 12:41, J. Jonik wrote:
>
> > Back to the Idling problems.
> >
> > Jim Adney asked if I have the 73 IAD and Breather, or if I kept the 72 IAD and Breather, when I switched engines. I have what came with the 73. I only now saw how the two aren't the same. The 73 has an air hose going from the back of the IAD to the breather.
> > The 72, that I took out of the car, has no such hose. Breather is the same except its hose vents down. (Mine always just vented into space but I THINK it was supposed to vent into the oil dipstick pipe.)
>
> You need to have matching breather and IAD. That includes the
> functional hose if you use the '73 parts.
>
> If you block off the hose and try to keep the '73 breather, you'll
> end up with no breather at all, which will end up pumping oil out
> around the rear end of the crank. Better to swap in the early
> breather.
>
> > So....thinking that if that IAD-to-Breather hose is the only
> > difference, I blocked off the hose to the IAD. Lug nut and hose clamp
> > did the trick. That helped cut the racing idle about in half, but the
> > irregular idle is again noticeable. And, still, the idle cannot be
> > set. It's all the way screwed down. When I open it a bit, yes, it
> > speeds up.
>
> Hmmm, that hose is supposed to pull some air thru the crankcase to
> ventilate it, as sort of PCV, positive crankcase ventilation. It
> shouldn't be able to pull in that much, because there's a small
> orifice in the cover of the IAD that limits the amount of air that
> can get in.
Does this '73 engine have vent ports on top of each head, with hoses
that lead to the air cleaner? (It would have, originally, if it's a
'73.)
If not, something else to check: Pull off the valve covers and check
the 2 valve cover gaskets. Make sure they are in position and in good
shape.
--
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Jim Adney, jadney at vwtype3.org
Madison, Wisconsin, USA
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