I was wondering if anyone that has an 944S (or S2 if they are the same layout) can help and have a look at their vacuum pipes on the bulkhead?
I have just completed a full engine rebuild and whilst marking everything up I have two vacuum pipes that seem stray. I am also having some running problems so would like to get the vacuum pipes correct before continuing the hunt for running issues.
This green pipe going through the bulkhead to the heater is stray, it did have a rubber end on it but that is now missing, where should this connect? As it had a rubber end on it I've eliminated it from going into the T piece.
This other T piece (purple line, below pic) on the bulkhead only has two connections, one to the valve on the coolant pipe that runs over the exhaust manifold and one going to the brake servo check valve, what should be in the third hole?
This is how I am currently set up with hoses, showing the two open pipes, the short green one going into the bulkhead and the right T piece in blue. Yellow line is between the fuel regulators and inlet manifold.
Onto those running issues, when I first drove the car on Sunday it didn't seem to want to idle when coming to a halt, also the same when I dipped the clutch whilst driving along, it would just stall although I could bump start it when driving with the momentum of the car. It drives great on the throttle so I'm not thinking fuel delivery.
When it stalled it did eventually start but this was after about 20 minutes being sat, I drove it home and it stalled on the drive and wouldn't start when I tried, just turns over and over. I left it for an hour and went back out where it started first time.
The next morning it struggled to start and had to give it some throttle but when driving this time it seemed to idle better when coming to a halt. I don't think this is a vacuum issue but would also like to hunt down what it is as I've got 500 running in miles to do before I can give it the beans.
My list of possible culprits,
DME relay, (ordered a spare anyway).
Idle Control Valve.
Vacuum pipes wrong, dissconnected.
J tube leaking air after the AFM (the pipe going to the oil filler/AOS looks loose going into the J tube).
Fuel pressure regulator.
Any ideas welcome.
...so well spotted and hope the repair works. I have had a look at the vac diagram and the green heater pipe must only go to the heater valve over by the PS reservoir. That is because it is an output to that valve, it must not go anywhere else or be 't' connected, as it needs to be a variable vacuum supply to the valve to operate it. Regards the thermo valve (21), it appears that the only diagram in the 944 parts manual to show the evap system is the diagram I posted. However, it doesn't seem right for the 16V models. So, I had a look at the 968 diagram for a clue, and that is closer to what you have. It seems there is no valve 21 on the later 16V models, and perhaps the system fitted in your car is a bit of both designs.. 
.