[T3] running rich and mystery material

[Dave]

[[[I checked the AAR before I installed it during engine assembly. The
spring turn freely and moved with the shaft it is hooked up to. I tried
blowing through it and when I would turned the spring I couldn't and then
when I released it I could blow through it. Was there anything else I needed
to check on it?]]]
 
That is exactly how to check the AAR on the bench, but you still need to
check the adjustment of the spring.
 
These AAR's have a metal spring wrapped round and round several turns around
the center shaft which opens and closes a passage for air to pass thru. When
the motor is stone cold (overnight cold), the spring is also cold, so the
spring is compressed, which rotates the shaft, which allows air to pass thru
the AAR and enter the IAD, which makes the cold idle speed go up in order to
compensate for the cold start richer mixture. [[[ Anytime extra air is
allowed to enter the IAD, the result will be an increased motor speed. As an
example - That is how our idle speed screw works; it allows a little more
air to enter the IAD (as opposed to a carbed car where turning the idle
speed screw mechanically rotates the shaft that the butterfly's are attached
to and therefore allows more air into the intake manifold) ]]] Since our AAR
is positioned inside the crankcase area - the motor oil splashes on the
metal spring, causing it to heat up and expand, rotating the shaft, causing
the AAR to close off the air supply and the idle returns to normal when the
motor is warm. Now the AAR is closed. (IIRC, the automatic tranny equipped
cars AAR is electrically heated instead of motor oil heated)
 
Watching your video Dennis, you have NO increased idle speed when cold, so
maybe your AAR is adjusted wrong so that no air can pass thru it when cold -
hence the suggestion to look at the AAR.
 
As you noticed, there is a little screw and a grade scale on the inside of
the AAR. [[[Be VERY careful of the tightening of this tiny screw. If you
strip it out, you'll have to go to a larger diameter screw, and the slot
provided for the screw is very closely sized to the stock screw - which
means you might have to widen the entire slot. That can't be fun. If you
leave this screw too loose after adjustment - and it vibrates out in use -
it falls right into your crankcase. That won't be good either.]]] There are
2 hoses attached to the AAR, one to provide filtered air (via the air
cleaner) to the AAR, the other connects the AAR to the IAD. Right now your
car runs good and idles when warm, so I'm thinking your AAR is closing off
when warm as it should.
When warm - if you unplug the hose to the air cleaner - you should feel very
little suction there, if any. (I don't think the AAR actually 100% closes
off, but very close to it) If when warm you do feel some slight suction, and
you put your thumb over the hose and the idle drops more than maybe a
hundred rpm. or more, then the AAR isn't closing off all the way and it
needs adjustment to correct.
When cold - there will be plenty of suction on this same hose, and putting
your thumb over the end WILL cause your motor to slow way down, too far down
to where the motor is choking itself out - kinda like what your cold motor
sounds like :-0
 
The adjustment is a compromise between enough of an increased idle to
compensate for the FI induced cold start richer mixture, and yet as the
motor warms up - it should drop down the amount of air it lets into the IAD
so that you are not experiencing a high idle condition as the motor gets
warm. Start off by making sure your AAR is closed when warm. That always
will be a constant. Then, the next morning see if you have a higher idle
speed when first starting up. Do the thumb test. If you don't have any
higher idle speed, then you need to remove the AAR, loosen the screw and
rotate the spring just one notch - a little rotation goes a long way! WRITE
DOWN WHICH WAY YOU ROTATED THE SPRING AND BY HOW MUCH. Right now I cannot
remember which way to rotate, but it's a 50% success rate. Tomorrow morning
check and see if your adjustment made a difference. If not, do it again. If
your next adjustment is not producing a change - then you are either going
the wrong way or your AAR is stuck. What you are shooting for is to have the
AAR fully closed when warm, but when cold you want a cold idle that is high
enough to keep it running when stone cold, yet not so high that your motor
is racing as you come to a stoplight.
 
I found it is best to wait to see the results of an adjustment until the
next morning. If I tried to hurry the process and started the car in the
morning - made an adjustment - checked it later the same day, then I thought
I nailed it. Only after an overnight cold start did I realize I still didn't
get it right.
 
As Bobnotch would say "I hope this helps".
 
  

Dave Pallo

'72 Square ~ Elwood

Fairport, NY

 

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