1st I must correct my last Post:
I wrote ...sensed by a position sensor...
but it is a position switch.
Sorry for this false definition.
@80/20
The only difference of Classic and NG is, that the "not closed" signal on the NG goes to the DEU.
The DEU now supply start valve position information to the CDS.
Also starter cutout on NGs is 55% N2.
...abnormal duct pressure is not as easy to detect when you move quickly from one start to the other...
QUICKLY???
Like alexban wrote before : "...you must monitor the engine param until eng stabilised..." .
So you have plenty of time to look for abnormal duct pressure.
Ingo