74 CIS wiring help please

[dburgoon]

I have been fixing a wiring debacle from the previous owner. He did some “custom” wiring and it ended in the whole harness burning. He also cut some wires and that’s where I need the help.

I have replaced both the engine harness and the fuse panel on the left side of the engine compartment. Part of the wiring on this panel is a 3 prong plug that sits behind the panel. It looks like there are 2 brown wires (grounds) and 2 red striped wires that go to it. I have the plugs connected but the wiring running to what I presume is the front of the car has been cut. Can someone help me out and telling me where these wires go. I will get some pictures after work to help out with the search.

Thank you,
Drake

[boyt911sc]

Drake,

Take some pictures and post them so others could give you a better advice. I would contact Dennis Powell aka Timmy2 from this forum. I go to Dennis P. for my wiring needs. Others would share their respective experiences regarding this matter. Good luck.

Tony

[angelny911]

I might have the complete warming harness which I took out of my 74 targa only change was to get rid of outside voltage regulator

[timmy2]

Rear window defroster wires if the 3 prong plug only has 2 actual contacts and is somewhat flat and black.

[dburgoon]

Here are a few pictures of the wiring in question. Based off the info from Timmy2 it might be the rear window defroster. So it has nothing to do with my issue.

The issue I am having is that I have everything seemingly hooked up right and when I turn the key to ignition the fuel pump turns on and I can hear the CDI box power on but it doesn’t try to start. I have power to the starter too.

[porschyard]

drake, i am working on some wiring issues my self on a 74 with a 79 3.0 dennis is correct, that is the rear window defroster wiring and enters the body to the left side of the left deck lid hinge. if you would like a pic. of where it enters the body let me know, richard

[porschyard]

drake, i have been neck deep troubleshooting a cis harness with multiple problems from another shop for the past 2 days and have just about finished up. i am not quite understanding your question/issue,are you asking if its normal for fuel pump to run and cdi to be energized (high pitch hum) when you turn the key to the on position if so this is normal, porsche did not use a fuel pump shut off contact until 1976 so all the eariler cis systems the pump will run when the key is on. hope this helps richard

[dburgoon]

Originally Posted by porschyard

drake, i have been neck deep troubleshooting a cis harness with multiple problems from another shop for the past 2 days and have just about finished up. i am not quite understanding your question/issue,are you asking if its normal for fuel pump to run and cdi to be energized (high pitch hum) when you turn the key to the on position if so this is normal, porsche did not use a fuel pump shut off contact until 1976 so all the eariler cis systems the pump will run when the key is on. hope this helps richard

I figured the fuel pump and CDI was correct, my ‘79 does not keep the fuel pump running but I thought I remembered the ‘74 being different in that regard.

My issue is that whenever I turn the key to try and start the car I get nothing. The car doesn’t try to do anything. I’m going to try and jumper the starter to make sure it’s good, but the car turned over before I changed the wiring just wouldn’t start. Now it’s not even turning over.

[porschyard]

the 14 pole connector on the relay plate is t14 term #1( yellow wire) is for the starter