Car is a 1973 1.7 with original D-jet fuel injection. Wire looks to be tan or faded brown, and exits from the wiring harness under the intake plenum on the passenger side along with a green-red wire that goes to what I think is the oil pressure sensor. I've tried to capture it in the attached picture.

Click to view attachment

So, where is this wire supposed to go?

Gary

brown wires are commonly the color of grounding wires on the 914. Don't recall any tan color coded wires so prob brown. There is a multi point ground connection on a 3 terminal spade connector on one of the case bolts at the rear of the engine. You could see if it traces to there but the other/loose end needs to find it's position. Throttle position sensor plug?

Here is the part of the schematic with the grn/red wire:
http://www.pelicanparts.com/914/parts/Elec...lectric_74D.jpg

Here is a diagram of the relay board the Cap'n is referring to:
Click to view attachment
12 pin plug located at lower right

Looks to me to be a white wire with a faded/stained grey sheath. That would make it the voltage source for the aux air regulator. Check for voltage with the car running, or trace the continuity to pin 12 of the 12 pin connector at the relay board.

The Cap'n

I know brown is usually ground, but I'll be darned if I can find a ground point around where this wire is. The ground point further back looks to have its full complement of wires in place.

There is a wire going to the aux air regulator already, so I don't think this is it. I thought initially it had to go to the cold start injector (?), but it would not be typical for Porsche to have put two wires into one crimp connection would it?

BTW, I hope I'm calling theses things by the right names. Sometimes it seems the more looking around I do, the more confused I get

Gary

Is the wire in question part of the black ignition harness or the grey FI harness?

The Cap'n

Good question. I better look before I answer. My track record on answering from memory isn't so good. I want to say it comes out of the black. It actually comes out under the intake runners, so it's not really visible, but I believe it's the same bundle that later goes to the distributor.

Gary

If it indeed comes through the black harness, carefully pop the cover off the 12 pin plug while it's still plugged in to the board, and identify the wire there. From that point, look at the wiring diagrams on the Pelican website and see what it is. Scary simple!

The Cap'n

It is indeed the aux air valve wire from pin 12 of the relay board. Now all I have to do is figure out what the aux air valve is wired to now. It's already got a wire spliced onto it, but I'll need to trace it back to figure out where it goes.

This is not the first wiring "mod" I've discovered on this car.

Thank you, Cap'n and others.

Gary

It's not all that uncommon to see the AAR wired to the 15 (+) terminal of the coil.

The Cap'n

And it looks like that is where it goes. Just out of curiosity, why would one do this? Is it just because the coil is closer and easier to get to? Guess I'm in the fix it right camp rather than the easy patch camp unless there's a compelling reason.

Gary

Easy place to pick up switched power.