[T3] Weird Idle Problem

[R. David]

> Sounds like you ~may~ have an air leak into your IAD. One possibility is
> your AAR. It is supposed to allow enough air into the IAD to slightly
> increase the idle on a cold engine, then when it warms up it cuts off this
> extra air so that the idle is set by the idle speed screw. So when the
> engine is cold; you should feel a suction on the AAR intake hose that
comes
> from air cleaner, and when it's warm there should be very little suction
on
> this hose (or none at all).

[[[The AAR never shuts off completely, so putting your finger over it and
feeling for suction doesn't tell the truth. The correct test is to cover the
opening with a warm engine and note whether the idle drops or not. It should
not.]]]

I didn't think the AAR completely shut off, but the vacuum difference is
very noticeable between a cold engine and a warm engine. And actually, if
there still is air drawn thru the AAR on a warm engine; it HAS to effect the
idle speed too... doesn't it? ANY air allowed to enter the IAD at idle will
effect idle speed, so I'm thinking plugging the AAR intake WILL ~slightly~
lower warm idle speed.

Now I gotta go check a warm engine ;-)........

Dave Pallo
'72 Square ~ "Elwood"
Fairport, NY