[T3] Engine Idle very low, once warmed up

[jaredkohler at gmail.com]

First, ALL of your replies are incredibly helpful. You're truly Type 3
Wizards and I'm very grateful and appreciate you taking the time to help me.

My auto trans AAR was not working as we all suspected. I began the
diagnosis after starting the engine (cold in AM) and allowing to idle for a
few minutes. I then pulled the hose from the AAR to the oil bath and
plugged it with my finger. Engine immediately died. This scenario continued
the longer the engine idled and the more warmed up the engine seemed to
get. So, I knew the AAR wasn't functioning as it should. Or did it not have
power?

I then checked my AAR power source which I had made during my FI
installation. It had juice. Strike 2! At this point, I'm betting, just as
you stated, the AAR is either stuck or has kicked the bucket.

Now, I turned to my parts bin and the mechanical (Manual car) AAR I had. I
figure, my Fastback is a manual car, why the heck do I have an Auto AAR?
This should have been my thinking during my FI installation. Strike 3! But,
we all learn from our mistakes. So, I began the process of removing the
Auto AAR and installing the Manual AAR.

Now with the Manual AAR installed, the engine would continue to idle with
the oil bath hose plugged with my finger, although very low. While the
engine was nice and warm, I adjusted the idle set screw (with lock nut) a
half turn. Wow! Now, I had an idle my ear and memory were happy with.
Still, I know I should get a Tach or an automotive multimeter to truly dial
it in. On my list and will purchase. I'll revisit the engine's true idle
rpm once bought.

Long story a little shorter and several test drives later, my Fastback no
longer has low idle as I idle at stop signs and stop lights! Wow, what a
difference! Yet, once I shut off the engine, shop at Home Depot, return,
start the engine, I get a 30 second (yes, I timed it) rough idle until the
AAR begins to warm and begin it's function. Once the AAR comes alive, the
idle speeds up, smooths out, and away I go without any dip in performance
throughout my travels home.

Leaps a bounds better than what I had been dealing with and a simpler
solution than I thought. Thank you all for steering me in the right
directions!

I'll keep you posted as I continue to fiddle and perfect.

Jared
Goleta, CA





On Thu, Aug 3, 2017 at 6:22 AM, Jim Adney <jadney at vwtype3.org> wrote:

> On 2 Aug 2017 at 22:20, William J wrote:
>
> > Point is as Jim said to make certain it's not the AAR axillary air
> > regulator you need to plug the end on the hose connected to the oil bath
> > air filter then adjust the idle speed . If you feel suction on that hose
> > when cold it's open as it should be and no suction when closed = normal
> > idle speed adjustment using the screw with the lock nut on top of the IAD
> > intake air distributor.
>
> One correction: Because these are imperfect valves, you will ALWAYS feel
> vacuum on that hose when you close it off with your thumb. The correct test
> is to note whether the idle speed drops or not when you close off that
> hose.
>
> When the valve is open (cold) there will be a large drop in idle speed when
> you close off that hose.
>
> When the valve is closed (warm) there will still still be vacuum there, but
> insignificant flow, so there will be little or no change in idle speed
> when you
> close off the hose with your thumb.
>
> To set your idle speed, you should either wait until there's no change in
> idle
> speed when closing off that hose, or you can set the idle speed while
> closing
> off that hose with your thumb.
>
> --
> *******************************
> Jim Adney, jadney at vwtype3.org
> Madison, Wisconsin, USA
> *******************************
>
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