Tech Procedure for CIS-E Poor Idling in EC

[steveb@newkla.kla.com (Steven Buchholz)]

Just got the March '95 EC in the mail last night and noticed a procedure for 
troubleshooting idling problems on cars with CIS-E.  It is gear for VWs, but 
applies generally to Audis as well.  It includes a discussion of the procedure 
and a troubleshooting flowchart.  The article starts on page 90.

Some quick observations & notes:
Causes of bad idle - vacuum leaks, dirty/defective idle stabilizer, basic mix-
  ture or duty cycle misadjusted, idle switch or switch wiring problem.
Vacuum leak sources - any hose, injector seals.  Carb cleaner can be used to 
  find vacuum leaks by spraying cleaner near suspect areas.  If idle speed 
  increases it means that the carb cleaner is getting sucked into the intake 
  through a leak.  Remember to check all those crazy Audi crankcase ventila-
  tion lines!
Check duty cycle - (Does everybody out there have one of those cool SunPro
  digital meters with the duty cycle setting and 5-cyl tach/dwell?)
Check idle stabilizer - Simple check ... turn ignition switch on but do not 
  start the car.  The Idle Stabilizer should be vibrating.
Check throttle switches - ECU doesn't go into idle control mode unless it sees 
  the idle switch is actuated.  

Steve Buchholz