1977 2.7 engine wiring problems
 

Hopefully I will get my rebuilt long block back in a few weeks and I have started to look at the engine wiring loom. Some previous owner has done some "modifications" to the loom and I have also lost my digital photos from when I removed the loom from the engine.

In this thread I will post questions and I hope to get some help identifying the cables and connectors.

First question: I have a brown/black wire close to the 14-pin connector. Where do this one go?

http://forums.pelicanparts.com/uploa...1294599359.jpg

14-pin wire connections.........
 

Henri,

I don't recall any brown/black wire in the 14-pin connector. But by looking at the picture, it could be coming from the other wire harness (taped) to the main wire harness. Could you post picture of the other end of the smaller wire harness? It is a ground wire and we could tell more about it if you could show us the other end of the harness. Keep us posted.

Tony

Thanks for the help. I found this thread:

http://forums.pelicanparts.com/porsche-911-technical-forum/229111-c3-engine-bay-wiring-diagram-pics-here.html

It seems that the single brown/black wire has something to do with the cruise control. My car does not have cruise control and I think a can just ignore that wire.

I have to correct this. The diagram in the link is not 100% correct. The brown/black wire goes to the safety switch in the air flow sensor. The connector in the picture above is supposed to be connected to a brown/black wire close to the relay panel.

Brown/black wire........
 

Henri,

That brown/black wire is not the wire that goes to AFS switch. I'll ask again, please post picture of the other end of the harness where the brown/black wire goes to. It will be a simple visual check if you still need assitance. Keep us posted. Thanks.

Tony

The Workshop Manual has 2 fold-out pages of the 1977 complete wiring. There is only 1 brown/black wire that I could find.

The 1977 came with an external voltage regulator mounted on the engine compartment electric panel

Top connector = T2k = "below regulator panel"

Bottom connector = T1a = "near regulator panel"



http://forums.pelicanparts.com/uploa...1295011283.jpg

Other end
 

On my car it connects here:
http://forums.pelicanparts.com/uploa...1295037034.jpg
I don't know what it does once it back there.

Henrik -

I have a '77 2.7L engine in my '74 911 and I am pretty sure I have that brown wire sticking out of the wire loom at the 14 pin connector just as your photo shows. I will try to remember to look this evening where/what it connects to and post back.

Tom

Henrik -

I just took a look at my car and there is a brown wire w/black stripes (the stripes run parallel to the wire, not perpendicular as your photo shows) in the same spot as your photo - right near the 14 pin connector. Unfortunately, it is not connected to anything; it's just hanging there, loose. I do have an external voltage regulator, as mentioned in an earlier post, which works, but must be connected using different wires. I looked at the wiring diagrams I have, but wasn't able to learn any more about the wire - sorry I couldn't help!

Tom

Thanks to all for the help - especially RoninLB with the wiring diagram in color. I have only the black/white version in Haynes, and it doesn't list the color of that wire.

I have checked the engine loom again and the brown/black wire goes to the safety switch, just like in the wiring diagram above.

http://forums.pelicanparts.com/uploa...1295212436.jpg

While digging around the relay panel I also found the other end of the wire. It was taped up and not connected when I bought the car. The safety switch was not active and the fuel pump ran when ignition was on when I bought the car.

http://forums.pelicanparts.com/uploa...1295212449.jpg

With the black/brown wire issue sorted it is time for two more questions:

#1 My har has an alternator with built in voltage regulator. This little thing was not connected when I bought the car. The colors of the wires suggest that it has something to do with the charging, but it looks too small to be the voltage regulator.

http://forums.pelicanparts.com/uploa...1295212975.jpg


#2 What is this? It was bolted to the relay panel and has a red and a brown wire going into the main loom.

http://forums.pelicanparts.com/uploa...1295213065.jpg

the 3 pin contraption is a voltage noise suppresor

leave it disconnected and you might as well remove it

it's a problem waiting to happen when connected to the external voltage regulator on the electric panel




http://forums.pelicanparts.com/uploa...1295244232.jpg


http://forums.pelicanparts.com/uploa...1295244257.jpg

This thread

http://forums.pelicanparts.com/porsche-911-technical-forum/229111-c3-engine-bay-wiring-diagram-pics-here.html

contains a wiring diagram for a 1977. Unfortunately it is a bit difficult to read and I have re-drawn it and corrected some small errors.

http://forums.pelicanparts.com/uploa...1297285723.gif

This has been quite helpful Thank you...My receiving wiring is a nightmare and And I am tracing wiring that has more crimps, wire nuts, and color changes than one would wish on no friend. I am interfacing to a Rebel wiring loom. Worst part of the process is figuring out where power comes in and goes out.

more wiring questions
 

Lower left connector in this schematic is a T shape One wire goes to the Tachometer. Other wire is Red and is shown going to the CDI unit. Where does it connect coming out of the T Connector? Thanks

Still wrestling with wiring. Any help is appreciated. As noted in my earlier post I am wiring the fuel pump relay into the 14 pin connector and beyond