Hey guys! I started doing a full restoration on my 68 vette back a few years ago, but stopped working on it for about a year (had to save for my wedding). I just picked back up and I'm at the stage where "i'll remember where this goes" has gone out the window haha. Im trying to wire up the distributor/ignition coil and while I labeled some wires, have no clue where others go -- including one with a missing end. Anyone care to help me figure out where these plugs and connectors go?

I believe the yellow and the blue both go on the + of the coil. Not sure about the green or turquoise wire. The broken wire I have no clue.

Some of them have orange paint on them --


that's just overspray from when I was touching up the engine block, so don't go by that as a wire color indicator!

Thanks for any help!

 

You should check to see which heavier wire had 12v in the key on position. Usually is a red wire and goes to plus coil terminal. See what wire is connected to the small right side terminal of the starter solenoid which sends full 12v to plus side of coil during cranking only. That wire and the 12v wire from the ignition switch should be the only 2 wires going to plus side of coil. Black wire(usually) from distributor goes to the negative side of coil. May be a tach wire going that goes to the negative side of coil too.

 

Started working on this early today, so I have an update. These connectors are from 2 different harnesses.

that broken wire goes to the starter. So I paired it with the unmarked wire that's in my hand (it looks black/white stripe, but the black is just paint). I believe that's the resistor wire. I linked the 2 together and ran it to the positive on the coil.

The other wires are all a part of a second harness that I'm about to get into now. Hopefully I'll report back after doing some research and ohming out to say everything is landed. Thanks!

 

The other wires run along a harness which connects to this box on the driver side front, up by the headlights -- anyone have a clue what this box is or what wiring diagram would show where these were landed? I'll continue searching in the meanwhile.

 

That is a Transistorized Ignition Control Box. That just means that your Corvette came with the factory T.I. System installed on it. They are a nice thing to have and frequently work very well.

There is a gentleman named Dave Fiedler who is the resident expert on the factory T.I. Systems. The system uses that little box and a special distributor. The harness for it is separate from most of the under-hood parts.

I had my system removed and rebuilt by Dave decades ago and then I bagged and tagged it and put it on my shelf in the garage. I am currently using a MSD Ignition system on my 427 today because I built a replica of the L88 engine with 12.25-1 Compression and needed a STRONG spark. The Factory T.I. is a great system and easy to use on a stock engine. Dave has come up with a better design for the board that mounts inside the box in your picture. Your cover looks like mine did before I cleaned the fins off allowing it to transfer heat more efficiently. I stripped it down and then painted it with black radiator paint. I hope you enjoy not having to deal with replacing points and condensers.

Best regards,
Chris

The T.I. System doesn't use a resistance wire to my knowledge. When identifying which wires go where on the coil be sure to look for information regarding the Factory T.I. System!

 

Appreciate the heads up! I was wondering why I couldn't find any straight forward info on it in all my searches. Time to read up! Thanks!

 

Welp -- after doing some reading and looking at pictures, it looks like the distributor that came on the car is just a regular points version... so I'm guessing that the previous owner bypassed the TI system. Not sure how/why they still had it connected to the coil (maybe that's what the yellow highlighted wire was doing? Coming out of that connector?). Regardless, I had already ordered a new distributor based on the one that was in the car (points), so I guess I'm sticking with that. At this point, I'm assuming its ok if I just leave the whole TI wiring harness disconnected and wire the car as a non-TI vehicle for now?

 

That is a shame as the T.I. system really made a great spark and worked so well. If you have no plans for it you might take it out clean it up and sell it. There is always going to be someone trying to maintain the T.I.System. They were used by GM starting in 1964 and the ones on Corvettes are premium.

I have a Billet MSD Distributor in my Corvette as it is connected to a MSD 6AL. The spark that bad boy puts out sounds like a welder spitting out multiple sparks at lower engine speeds. I have it now working with my Holley Stealth Sniper EFI system and I still have a spinning cable for my mechanical tach in my 1968 C3!

Good Luck!
Chris