This part came with the replacement CIS engine. The car had an AFC injection system prior. I donor know how to actuate this part or what to plug it into.
Joe

 

If I were to guess, someone Jerry rigged a cold start injector. Not a factory set up for sure.

 

actually looks like the "frequency valve" that was part of the add on control system for epa compliance when a euro spec car was brought into the usa

 

Looks like an injector to me...

 

It is an injector, but on a CIS car, they were used as an additional control pressure regulator in CIS-E. Something electronic , probably connected to an O2 sensor would modify control pressure to change the mixture by pulsing the injector, or not. One side would be seeing control pressure, the other would connect to the tank return line.
jp 83 Euro S AT 55k

 

What happens to performance and cold start if I just ignore it?

 

This engine is a euro model m28/11 with 300 hp

 

First 928 I have heard of with CIS-E. Not sure what will happen if its not working. Is there no sign of where the open end might connect, or any wiring to fit it ? It shouldnt affect cold start, as the O2 sensor wont be doing anything at that stage . I would check hot mixture somehow (sniffer up the tailpipe?), and see what sort of mileage you are getting on the highway. Last long cruise (400mi) I did I got ~21 mpg (US GAL), 11L/100km.
jp 83 Euro S AT 55k

 

Certainly looks like an injector.
Where does the other end of the hose hook up??

 

Thanks again for all of the great feedback. I am going to simply operate without it and see what happens on the assumption that it is designed for EPA compliance.

 

I thought only 928's destined for California had KE-Jet? Guess someone just grafted it on since you said it used L-Jet before.