RE: timing quirks; and other sundry

["Dupree, Jim" <dupree@alldata.com>]

 I did a little digging on the Digital Idle Stabilizer  (DIS) system and it
seems to be a system used mostly on California vehicles 1980 through 1983
(both 4 and 5 cyl. cars). It may have been used on some 1984 cars but I'm
not sure. 
It is a small black box mounted with the Electronic Ignition Control Module
(either in the drain tray ahead of the windshield or in the glove box). It
has 2 round 3 pin connectors that plug into/onto it. It is wired inline
between the Hall generator in the distributor and the Ignition control
module. It electronically varies the signal from the hall generator  to
change the ignition timing, keeping the idle speed constant. It is a
relatively benign system (until it fails) since once you get above about
1200 rpm it no longer influences timing. It can be bypassed simple by
unplugging the 2 connectors and plugging them into each other. In fact I
have seen U.S. federal spec cars that don't have the DIS box but have the
plugs connected together. It has been known to be a trouble spot on the
earlier cars, no starts with no spark, dying hot, etc... If you have one of
these on your car and you have ignition problems check the connectors here
for corrosion or loose fit and/or bypass the box.
I recently added a DIS to my 78 VW Camper bus since the idle speed is so
easily influence by the engine temperature of the air cooled engine. Now it
can idle at a decent speed cold and not be racing at idle when hot. The aux.
air regulator VW used was not enough to give satisfactory idle speed under
the varying temperature the air cooled engine goes through.
Jim Dupree

		-----Original Message-----
		From:	Huw Powell [mailto:human@nh.ultranet.com]
		Sent:	Tuesday, April 27, 1999 10:48 AM
		To:	Dupree, Jim
		Cc:	Audi Fans
		Subject:	Re: timing quirks; and other sundry

		> What year is your coupe?

		the engine control systems are still 1982.

		> Some of the Audi's had a Digital Idle Stabilizer that
advances and retards
		> the ignition timing to control the idle speed. It has a
limited range that
		> it can adjust with-in  (8or 9 degrees?) and if you raise
or lower the base
		> idle speed enough it will sit at one end or the other of
its range. If your
		> car is equipped with one , the proper timing procedure is
to disconnect and
		> bypass it and then adjust timing, idle speed and fuel
mixture.

		Oh yes, the step I'm always to lazy to do... thanks for the
reminder!

		> I believe
		> this was eliminated with the introduction of CIS-E in 1984
but I would have
		> to look though my Bentley.

		That idle stabiliser is one of those things I still have to
trace and
		figure out before I tear it off to do the CIS-E
conversion... 

		-- 
		Huw Powell

		http://www.thebook.com/human-speakers

		82 Audi Coupe; 85 Coupe GT
		http://www.nh.ultranet.com/~human