[T3] Engine Idle very low, once warmed up

[Jim Adney]

On 2 Aug 2017 at 18:35, Jared Kohler wrote:

> Well, did my idle adjustment (when nice and warm) after a long drive
> and she still acts the same. I made the adjustment when she was idling
> in the garage and did notice the rpm increase. I shut the car off,
> then started again. Same super low idle. Gen light flickering it's so
> low. Yet, when cold (first thing in the AM) idle is nice and high.
> Stays running strong. 

You need to wait until your engine drops to that super low idle, then adjust 
the idle speed.

BTW: Are you using a tach to measure the idle or just going by ear? If by 
ear, then we don't know what "super low idle" actually means. I recommend 
using a tuneup tach to do this, just so you have a real number to shoot for.

> I'm wondering if it's not the vacuum operated sensor to the right of
> dist? Mine is electrically operated. Perhaps it's not closing as it
> should? Or opening as it should? I can't seem to get much info on
> these sensors. Books seem to glaze over their function and importance.
> I do have a mechanical one in my parts bin. Considering swapping to
> see if it makes a change for the better! 

As William said, the electrical one is for AT cars, while the mechanical one is 
for MT cars. Both are temp (not vacuum) sensitive. They open and close to 
allow more or less air to get in, adjusting the idle speed in response to 
engine temp. It's called the Aux. Air Regulator (AAR.) Adjusting the idle 
before it closes will give you the symptom you describe.

Both versions have a history of getting sticky, or getting completely stuck, 
after all these years. When that happens, operation and idle speed can 
become erratic. I can fix the straight mechanical ones, but I don't have a 
solution for the electrical ones.

Either one should work just fine for you, as long as it isn't sticking. Of course 
the electric one will need to get powered whenever the engine is running or 
it won't respond correctly. Is it powered now? If not, I can tell you where to 
get its power from.  

> P.S. A few years back, I think I had you rebuild my FI fuel pump? It's still working perfectly!!

Glad to hear it, but that's exactly what should happen.  ;-)

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