72 Inline 6 Engine Wiring Harness help (pics included)

[WB72]

I have 2 questions, maybe three.

1.) What does this connector connect to? I'm assuming that the connector is broken, so I will need to replace it, but I don't know what To attach it to.

2.) I forgot how the wiring harness was laid out, does anyone have a basic layout on how the harness sits in the engine bay for a I6, not a V8?

3.) My mono bore Carb has electrical connections to it, one connector as well as one wire to a solonoid, will I need to keep them or are they just for emissions?

[lemansguy]

any pics from further back? also, have you tried tracing the wire at all? i can go home and take a look at my harness tonight. Im getting ready to pull my I-6 but havent removed the engine harness yet. Finished labeling the body harness last night

[WB72]

I have looked at the pics I had taken before disassembly and they aren’t as good quality as I expected. The engine is greasy and I can not determine which branch of the harness is which.

As for tracing it back, that is an option, but I thought that it was so unique that someone on the forum would recognize it.

The wire is black, second last wire in that leg of the harness.

['68OrangeSunshine]

Did your L6 originally have an Anti Dieseling Solenoid?
My '68 292 didn't have one, but they came later. I don't recognize that connector. An ADS is probably what the electrical connections to your Monojet are. They keep the engine from running on after the key is turned off. Usually caused by crappy gasoline. I never needed one.
Another guess for the broken connector would be TCS [Terminal Controlled Spark] -- an Early '70s emissions gimmick that didn't really work, but made politicians and the press happy. The less they understood about performance, the happier they were.
If your truck runs fine now, re-attaching these connections won't improve pereformance, whatsoever.
What about the Choke? If you have a manual choke knob on the dash, then it's not electric. If no choke knob, it could be for an electric choke. You will need choke control.
Later, when you're detailing the engine, you can strip obsolete wires out of the harness and rewrap with non-stick vinyl tape, like OEM.
On the L6s, two big wire bundles come out of the Bulkhead Connector. One goes left inside the fender/fenderskirt to the radiator bulkhead, where it splits off to lights, horn, regulator, alternator, with one run going along the top of the radiator wall across to the passenger side where it connects to the fender terminal and joins a lead [fusible link] from the battery positive side. The other bundle from the Bulkhead Connector turns right across the curved part of the firewall. Some lines split off and connect to the Starter, Transmission, and some lines run inside the clips in the valve cover going to Distributor, Coil, water temp probe, and possibly Carburetor. [Electric choke, ADS.] Fuel and Vac Advance lines are also clipped on the valve cover going to the carb.
This is from memory. I may have forgotten a circuit or 3.
Points or HEI?

[WB72]

That is great info 6i8OrangeSunshine. Thanks for that.

Would I be wrong to assume that connector may have come from the 3 speed manual transmission? I have found a photo that I took prior to disassembly that shows a wire going to the transmission. I snooped around to find a broken plastic piece on the bottom left side of it. Now I am not sure if or how it can be replaced. Or even what it’s function is. The connector looks like it was one piece and crimped onto the harness originally.

There is no oil leak at the trans at this point, but may get something when driving.

Any idea if it is for the transmission?

[randy500]

Your last post makes it very clear...I couldn't figure out the spring hanging from the connector...its from the broken switch on the transmission.
It is transmission controlled spark (TCS) wiring and is not needed nor wanted. Just tape it off after prying the broken switch part from the connector.

['68OrangeSunshine]

Originally Posted by WB72

That is great info 6i8OrangeSunshine. Thanks for that.

Would I be wrong to assume that connector may have come from the 3 speed manual transmission? I have found a photo that I took prior to disassembly that shows a wire going to the transmission. I snooped around to find a broken plastic piece on the bottom left side of it. Now I am not sure if or how it can be replaced. Or even what it’s function is. The connector looks like it was one piece and crimped onto the harness originally.

There is no oil leak at the trans at this point, but may get something when driving.

Any idea if it is for the transmission?

The only electric connection to a 3-speed Saginaw transmission, will be the back-up light switch. If your back-up lights go on when you throw it in reverse -- you're good. There are no Neutral Safety Switches on GM manual trannies.
I'm not an expert on the Sag, both my rigs have the 4-speed Muncie SM465.