So I'm looking at the Auxiliary Air Regulator in my 1.9L. It is supposed
to bypass a little air around the throttle when cold and give the engine
a little more pep. 12V from the fuel pump relay applied to its terminals
causes that bypass to close after a couple minutes. At this point the
engine can presumably get along fine without it.

So Bentley's (24.28) gives us a simple test to see if the thing is
working: start the engine and while cold, pinch the rubber hose. The
rpms are supposed to drop.

Well, they didn't so I moved to the next test: check to see if the AAR
is getting 12V when the fuel pump is on, and it does.

Then to the bench: you can look through the AAR and there is a disc
blocking the passage, but there is a small hole in that disc which makes
it easy to blow through. When 12V is applied to the AAR, the disc slowly
rotates so the little hole is no longer visible after a minute or two
and it's hard to blow through.

So -- the AAR is fine, the hoses are fine, but pinching the hoses
doesn't drop the rpms, as Bentley's say it should.

--

Mike "Rocket J Squirrel" Elliott
71 Type 2: the Wonderbus
84 Westfalia: Mellow Yellow ("The Electrical Banana")
74 Utility Trailer. Ladybug Trailer, Inc., San Juan Capistrano
KG6RCR