Hello. I was working around the carbs this weekend and noticed that the vacuum line was disconnected from the distributor. So I reconnected and traced the vacuum line back to the thermostatic vacuum switch, then I noticed that there was a nipple on the switch with nothing attached and no vacuum line floating around anywhere. I checked he workshop manual and it states that there are three nipples marked C, D and MT, but on my switch there are four marked C, D, MT and FI.

Does anyone have a diagram of how the vacuum lines are connected? I wanted to make sure the lines are routed correctly.

Thanks!

 

Anybody?

 

I know very little but here goes...

I had these on two S1s. But I disconnected them both early on (no need to remove from manifold). I don't know the symbols. FI might be fuel injection on later cars?? One barb receives manifold vacuum. Another goes to the dizzy, to apply vacuum retard before warmup. This is agreed to be useless and can be removed, making the dizzy centrifugal advance only as it was before, but without pollution-related retard. It never had a conventional vacuum advance.

There's another vacuum circuit to the air cleaner. It operates flap that collects exhaust-manifold-heated air during warmup. I think there's an air temperature sensor for that one, but it might also involve the thingy you are investigating. Lastly there is a smog pump and (on some models) a gulp valve. I think there might be vacuum control in this circuit to turn it off after warmup...but sorry, I can't remember much. This stuff was on my S1s for a very short time. To repeat, though, IMO you can dispose of the entire system and be better off.

 

Thanks Robert! I appreciate your reply.