Idling control - Audi 100 '89

[quk@isham-research.demon.co.uk (Phil Payne)]

In message <00be01bd3d10$0c6ec900$1e2b989e@dboyd.demon.co.uk> David Boyd writes:

> I recall a discussion some time ago on the List about the effects on idling
> of removing the dipstick or the oil filler cap - my Audi 100 falters if the
> dipstick is removed when idling and stalls if the filler cap or indeed the
> crankshaft vent hose is removed. It has also just had its annual statutory
> vehicle test and failed because the CO emissions are too high. I suspect the
> two may be connected. The engine seems otherwise OK.

No, it's supposed to do that.

It's running rich, and it's an easy if very delicate adjustment.  Get the 
engine hot and idling with a CO meter probe up its bum, and use a _LONG_ 3mm 
Allen key down the hole between the air mass sensor plenum chamber and the fuel 
distributor.  Don't make the mistake I did and walk into a tool shop asking for 
a long 3mm Allen driver - ask for a Bosch fuel injection adjusting tool.  
 
Make _very_ small adjustments - just one or two degrees at a time, it's _very_ 
sensitive.  Pull the tool out after each touch, and blip the throttle.  You 
should be able to dial in any CO value you want.  Anti-clockwise to lower CO.

DON'T LEAVE THE TOOL IN WHEN YOU BLIP THE THROTTLE.
 
Check, also, that the correct MoT guidelines are being applied to your car.  
The limits depend on year of manufacture - for 1970-something cars the only 
requirement is no visible smoke.

-- 
 Phil Payne
 Committee Member, UK Audi [ur-]quattro Owners Club