The cold start valve is turned on by the fuel pump relay. It's a 12v signal, you can think of it as a square wave of some duration proportional to the temp.

__________________
Regards

Warren

Currently 1965 220Sb, 2002 FORD Crown Vic Police Interceptor

Had 1965 220SEb, 1967 230S, 280SE 4.5, 300SE (W126), 420SEL

ENTER > = (HP RPN)

Not part of the in-crowd since 1952.