Re: Tech Procedure for CIS-E Poor Idling in EC

[rdh@sli.com (Robert D. Houk)]

   ...
   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!

I've used water in the past in much the same way (water seals the leak,
unless it's really catastrophic, and doesn't "wash" nearly as much gunk
into the leak/intake system... of course it doesn't leave the engine
nearly as cleaned off when you're done, either!).

   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?)

Yup - best single "Audi" tool I've ever bought. Highly recommended!

   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.  

Dunno how many variations of the breed this applies to, but on the Hitachi-
equipped UrQs, tripping the WOT (Wide Open Throttle) switch at idle (i.e.,
both idle and WOT switches closed) forces the Freq Valve to 50% -- kind of
a "self test", and one of the easiest "sensor" tests I know of.

					-RDH