If the ECU didn't see the engine RPM via the distributor hall sensor, the
engine wouldn�t run. Basics. How does the fuel injection work? The
injectors, all of them are fired once each engine revolution. This is
accomplished by the ECU seeing the coil pulses and firing every other one.

Now, if the engine is not maintaining idle with the stabilizer bypassed,
then your basic settings are way off. This may be why you are not seeing
expected speed changes with the auxiliary air regulator. You are relying
on the stabilizer way too much. The idle should be set to 850-950 rpm
without the stabilizer. The stabilizer should only come into play from
excessive O2 sensor swings or excessive idle loads such as heavy
alternator demands. The power steering and AC should have boost solenoids
to increase the idle for their needs.

Dennis

-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of
Michael Elliott
Sent: Monday, October 29, 2007 6:09 PM
To: vanagon@GERRY.VANAGON.COM
Subject: Definitive test for Hall > ECU?

My Hall sensor seems to be working because when I bypass the idle
stabilization unit the engine speed changes (it drops, I need to set up
the bypass screw to keep the engine running). I think this means that
the ISU "sees" the Hall sensor.

How can I confirm that the ECU is also seeing engine rpm?

--
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