[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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