fuel pressure gauge

[Kent]

My '91 200 20V is hard to start, like the drain back check-valve 
has failed.  So I bought a fuel pressure gauge to test it. The
gauge is geared to American cars, and expects a Schraeder valve
on the fuel rail to which to hook the gauge.  Of course, I can't 
find one on my Audi.

Anyone have any ideas as to how to connect the gauge to the
fuel rail/line to test the fuel pressure?

Thanks.

-- 
Kent McLean
'91 200 TQA #1, for sale
'91 200 TQA #2, no name yet
'94 100 S Avant, "Moody"
'89 200 TQ, "Bad Puppy", up in smoke