1986 S2 (4.7 16V Auto)

There are three vacuum connections on the front of the plenum. One of them is the (relatively) wide pipe for the air-con valve thing. The other two I struggling to identify.

One is a fancy metal pipe with an M8 banjo connector. The other is conventional hard plastic pipe that connects with a rubber bend. I've looked at lots of diagrams but I'm struggling to identify them. I assume, one of them is the vac pipe to the gearbox but can't tell which.

 

Fancy metal pipe w/banjo is for the automatic gearbox.

 

I am not entirely familiar with your model year but it has two different vacuum systems- active and passive. The active system supplies vacuum to those users that need to respond to actual vacuum conditions in the inlet plenum and typically applies vacuum to the fuel pressure regulator, fuel pressure damper [or dampers?] and also to the auto gearbox modulator that smoothes out low load shifts. The passive system supplies a deep vacuum for the HVAC system and is taken from the brake booster via the small blue black check valve and the vac reservoir I also understand there is a passive vac line to the cruise control on your model year..

The vac line for the gearbox is very easy to identify as it runs down the front of the firewall and then under the heat shield and off to the gearbox via a hard line strapped to the top of the torque tube.

 

The hard plastic pipe goes to the EZF ignition module in the passenger footwell.

 

Great - thanks everybody for the info.