4K QUATTRO IDLE PROBLEM AFTER INJECTOR OVERHAUL

[Huw Powell]

> I recently went to an independent shop in the area that flushed my
> injectors, replaced two injectors and all injector seat seals. Car
> runs much better, as one injector was squirting, not spraying.
> However, now, the car idles low, and when the car is warmed up, when
> I let off the accelerator (while driving), the idle dips to about
> 5-600rpm, which causes stumbling to the point of almost stalling.
> Then it immediately spikes back up again to normal 

It sounds like your car was "tuned" to run with air leaks around the 
injectors, and possible inaccurate fuel delivery as well.

If the baseline fuel mixture (adjusted with that 3mm hex while observing 
  actuator current or measuring CO) is a bit off, the idle hunting you 
describe is very common.

You might be able to adjust it by "ear," if you are lucky.  get a handy 
3mm T-handle hex key and find the hole between the air boot and fuel 
distributor.  Make sure the socket it goes into is clean, some carb 
cleaner can help here.

While adjusting, keep track of exactly how far you turn it, and which 
way, in case you mess it up more than you fix it.

The odds are, the car was running lean, and so the mixture will have 
been set richer to offset that.  So while the car is idling warm and 
exhibiting the idle hunt, you want to carefully turn the screw 
counterclockwise, about 1/8-1/6 of a turn at a time.  After each small 
adjustment, remove the tool and blip the throttle to let everything 
settle down.  You might manage to "tune" the problem out.  Especially if 
this is all it is.

You'd still better take a good look for air leaks, loose hoses, etc., as 
some may have been knocked around while the car was worked on.

-- 
Huw Powell

http://www.humanspeakers.com/audi

http://www.humanthoughts.org/