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With the auto vac line it just dawned on me its the hard line off the top of the manifold. I feel a little dopey
The trans line is from the same source as the computer. DEFINITELY NOT sourced from the brake booster. The brake booster vacuum line scavenges the vacuum reservoir for the 'constant vacuum' units, which is why it has the little one way valve. The trans has to track the variable manifold vacuum, so it knows if you plant your foot, or button off the loud pedal.
The hoses under the RHS mudguard are emissions hoses. They handle fuel vapour from the fuel tank, through the carbon canister, a couple of vacuum valves involved in opening up this system to draw the fumes into the inlet manifold to be burnt up. The 'Y' piece under there is common failure point and a source of fuel smell.
I've attached a schematic of my 'home made' vacuum system. It's bound to differ from yours but the theory is the same.
On my '82 its the copper pipe on the top front of the air intake.
"On the top of the intake plenum (what Porsche calls the "air distributor") is the vacuum source for the auto transmission. (manual, p. 26-3)" Quote from awhile back.
I cant drive it yet to check the modulator adjustment so I am sorting my plan to fine tune the whole system.
Looking at the picture below I think I have it all correct.
Is where I have labeled Throt adjust correct to take out the fine slack. There is no threaded portion on the cable end itself. I guess it once did but has been wound in due to stretch. I appreciate WOT is done at the pedal.
I have finally got it registered. I took it out for a run today and the small auto modulation adjustment I made has almost fixed the shift feel. Just a little more fiddling with cable tensions etc to get it where I want it. More importantly I have no idea what the tune is like. I know it was set rich when I first started it and adjusted the CO setting to around 400 ohms but in reality I have no idea where it is at. It does feel a little sluggish however runs and starts smoothly so hopefully not too far away from the optimum. I still need to do the TB and WP and associated tasks in that area before I lean on it too much. A bit busy over the next six months so I will need see how I go.
