'85 ur-q Cold Start Problem Fixed

["Mike Hopton" <mike@genesis-microchip.on.ca>]

     Ah, at last a couple of cold nights in Toronto to check if the cold start 
     problem with my '85 ur-q has really been fixed, and yes it has.... I think. 
     
     Turns out the temp switch that controls the pressure from the inlet 
     manifold to the control pressure regulator was faulty. We checked the 
     control pressure with the engine warm and found the pressure wouldn't drop 
     during deceleration, my mechanic was just about to unscrew the temp switch 
     and test it, when one of the air lines came off in his hand. Replaced the 
     switch and everything seemed okay. 
     
     However on the drive home the car would stall coming up to traffic lights. 
     Unfortunately my mechanic had adjusted the CO mixture with the faulty temp 
     switch and so when the temp switch was replaced the CO mixture was off. 
     Sorted that out last night and everything seems fine, I only had to turn 
     the CO mixture screw by about an 1/8th of a turn and checked that the duty 
     cycle at the frequency valve was 50:50 with a scope (still fluctuates with 
     the O2 sensor at idle). Is this good enough or do I need to measure the %CO 
     and if so how? When my mechanic adjusted the CO he just used the frequency 
     valve duty cycle and his "judgement". What do you think, should I get it 
     adjusted at Audi again? Unless I hear that I may damage the engine, I don't 
     plan on getting it adjusted.
     
     Regards, Mike