[T3] Idle and Air....

[Jim Adney]

On 12 Nov 2012 at 10:48, J. Jonik wrote:

> About irregular idle on 71 (w/ 73 engine) FI Std....

> A new thing...a big clue probably.   I just fiddled with a few
> things...turning the manifold hose things to assure
> snugness...tightening up a few ground connections...etc...and low and
> behold a lot of the irregular idling went away....   BUT....the engine
> was now idling too fast, so I tried to close up the idle adjustment
> screw a bit and found that it was already as far down as it can
> go...bottomed out !  ...and still the too-fast idle.  It was almost
> racing. 
> 
>   Does this point to definite air leak somewhere in manifold...the big hoses, or the gaskets?

Do you have the right intake port gaskets: the phenolic ones, not the 
metal ones? If you have the metal ones (for Beetles), you need to 
replace them with the correct Type 3 FI plastic ones. Unfortunately, 
the correct ones for our FI cars don't come in any gasket set.  

You may have leaks at the big hoses, due to their having an offset 
from previous careless assembly. You've taken them apart, and now the 
offset is turned the "wrong" way. Hose clamps on both ends of them is 
the rude and crude solution, but I would start by pulling all 4 hoses 
back onto the intake air runners, then loosening ALL the bolts for 
both sides AND the middle, and then moving everything around to get 
the best alignment possible.   

Then tighten all three up, bend the air tubes to line up, and slide 
the hoses back on. At this point, the hoses will be offset, but the 
joints won't be. The hoses will straighten out in time, but for now 
you'll need to stop the leaks there. I'd recommend nylon cable ties; 
they will do the job while still having some resilience.

In a couple years you can remove the cable ties.

>   Or is this about the Pressure Sensor? When I pulled off the hose,
> idle went down but was irregular. 

That sounds like it's working correctly.

-- 
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Jim Adney, jadney at vwtype3.org
Madison, Wisconsin, USA
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