1970 914/6 Harness Horror, Main Wiring Harness Connection Options

[Howie149]

I have a 1970 914/6. When I pulled the motor out, the 14 pin Main Harness that sits on the Relay Board in the engine compartment came apart. Thus I have no idea which wire goes where. I have 6 wires. (2 are grey and black and go to the transmission back-up switch/sender. 1 Green and brown and 1 Green and black go to the oil pressure and oil level senders. 1 Black and red goes to the coil and I'm not sure about the black and blue/purple.) I have attached a picture of the harness below.

I would enjoy any guidance on where to plug these wires.

Car won't start and it keeps blowing fuses which I assume is either a problem with these wires or the ignition system/distributor needs an overhaul.

[Dave_Darling]

If the wiring follows the same convention as the four-cylinder cars, the black/purple is the tach signal wire. It would likely have gone from the coil (-) terminal through the relay board to the tach.

--DD

[ClayPerrine]

If the wiring follows the same convention as the four-cylinder cars, the black/purple is the tach signal wire. It would likely have gone from the coil (-) terminal through the relay board to the tach.

--DD

Actually Dave, on a six, it comes directly off the points. The negative coil terminal on a six is connected to ground. The positive comes from the CD box output. That's why they need a tach amplifier plugged into the relay board.

This is the diagram of the ignition wiring from a early911/914-6.



#6 is the coil. #5 is the distributor, and #7 is the engine. On the distributor, the black wire is the trigger to the CD box, the black/purple goes to the tach amplifier, and the white is actually a braided shield wire that is grounded on both ends. On the coil, the blue/yellow is the pulse out from the CD box.

This is the CD box diagram.



The only additional wire is the red switched ignition power wire. You still have the blue/yellow that goes to the positive side of the coil, the black wire which goes to the points, and the braided shield which goes to the negative side of the coil and also to ground.


The Tach adapter on yours is wired to replace the tach amplifier that is NLA from Porsche. I had to do the same thing on my car. If you can find a factory tach amplifier, the early 911 concours guys will pay through the nose for them.

I have a hand drawn pinout diagram, with proper wire color codes, for the six relay board in the garage. If you still need it tomorrow I can copy it and upload it.