z driver 88t

1984 US model 16V, manual trans.

I'm in the process of putting together my "new" used engine from 928 INTL using all the known good parts off my old engine and am wondering about two items I can't seem to find in the parts catalog.

The black plastic cylinder on top of the fuel driver's side fuel rail has a cord that leads to the top of the bell housing. It does not seem to lead anywhere else. When I pop the top off the cylinder there appear to be two small contacts inside. Any idea what this is or what it does?




Second is a vacuum operated device on the passenger fender. Again, anyone know what it is or what it does? Thanks.

wpgshark

I believe that is a sensor port to detect TDC. I have it on the 88 but not on the 89.

Adk46

I've read that the first item is something the factory had use of, but not us. Leave it, yank it out, whatever you like. On my '87, the wires lead to a device behind the crank position sensor.

The second item: it is in the general vicinity of the device that controls the operation of the air pump on an '87, which might be in a partially disabled state - like mine and others who have removed the air pump. Wild guess.

ROG100

Item 1 - Timing Mark Sensor 911 606 108 00
Item 2 - Control Valve 944 110 429 00

wpgshark

Second needs a close up, but looks something like the valve used to control air from the air pump being injected into the exhaust before the cats.

davek9

Yep Item #1 was a "test" port for TDC and is no longer used by any current Diagnostic equipment.
Leave in place or remove it, makes no difference unless you are building a concourse car.

z driver 88t

Ah, Thanks everyone.

Roger. A quick Google search on that second part number shows it is part of the fuel tank ventilation system and presumably serves some mildly important function. I am continuously amazed at the complexity of design Porsche is willing to throw at a problem when compared to Japanese counterparts of this era. I love the 928, but sometimes it just seems like complexity for complexity's sake.

WallyP

"I am continuously amazed at the complexity of design Porsche is willing to throw at a problem when compared to Japanese counterparts of this era."

I have never seen anything more complex than Japanese vacuum systems on the earlier emission controls - like a vacuum control box with nine connections on my wife's Isuzu Trooper, or the non-rebuildable compound two-barrel carb on the same vehicle...

Tomkat80222

A quick Google search on that second part number shows it is part of the fuel tank ventilation system and presumably serves some mildly important function. I am continuously amazed at the complexity of design Porsche is willing to throw at a problem when compared to Japanese counterparts of this era. I love the 928, but sometimes it just seems like complexity for complexity's sake.

This is so true. Engineer job security. I have had to take on the mantra of "There is more to life then reliability." The Japanese cars are so boring starting up everyday and running forever with no complaints.