Frequency Valve - Turbo engines

["Scott M." <scottmo@teleport.com>]

As Phil and Rolf mentioned the frequency valve was done
away with around the mid 80's when the Naturally Aspirated
(NA) Audi engines used the differential pressure regulator
on the side of the fuel distributor to adjust the mixture. 


The Turbo Audi I5 engines sold in the US continued to use
the CIS frequency valve in the MC designated engine found
in the  1986-88 model 5000T/Q and the 1989-90 200TQ and
from 1989-1991 in the FWD 200T. The 1991 200TQ with the 20V
Turbo 3B engine threw out the whole CIS system and went to
the Motronic with electronically controlled injectors.

HTH
Scott M.
89 200TQ