ur-Q Fuel Problems

[scott.john.mockry@bangate1.tek.com]

Phil originally asked....this CIS fuel injection question on his UK 88 ur-Q
>> >>a)   Why is the quiescent position of the air volume sensor plate
>>      that controls the fuel metering head given as:
>> 
>>                       > "1.9 + 1.1 mm" ?

I (Scott M.) responded with the following
> The 1.9 + 1.1mm means that the minimum height should be 1.9 mm but the max
>height is  allowed up to 3.0mm, in other words the plate height should be between 1.9
>and 3.0 mm

>Mark  responded with:
>NO IT DOESN'T.  It means that the optimum (new) setting is 1.9mm.  But if
>you're lazy or sloppy you can set the adjustment to being up to 1.1mm greater
>than the optimum setting.  In other words set it to 1.9mm if you have the
>time. 

Scott responds again:
Well, I'm neither lazy nor sloppy when doing automotive 
repair or service but I did do a lazy and sloppy job of explaining this 
"clearance" and  should have clarified my statement:  The specification 
indicated  1.9 +1.1mm is what is "allowed" by VW/Audi when "checking" the height.

Phil originally was really asking "What height should I adjust this darn thing to?"
 
Yes, when you are re-adjusting the height and want it to be correct "like new"
as the factory originally set it to, you should adjust it to the 1.9 mm spec 
as Mark so "kindly" articulated. Yes, Mark is also correct about setting the valve
clearance right on, especially on air cooled engines. Many technicians use go/no go
feeler gauges which don't do a great job of getting the clearance right on. The valve
timing does change as you move away from the ideal clearance.

As someone who used to drag race VW bugs 20 years ago  (Sorry, I must have been
too lazy and sloppy back then to afford a Porsche 911, ok so I was only 16 years old) 
I am well aware of the effect of  having your valves adjusted correctly when I was
 taking a low tech VW air cooled engine and revving it to over 7500 RPM while I
cruised down the 1/4 mile in  14.0 seconds @ 95mph.  The stock Porsche's, Corvettes and
Camaros didn't really like to get beat by my lazy and sloppy VW back in those days...........
I suppose they would not like it much these days for that matter.......
Enough rambling from my ruffled feathers....

Scott M.