The starter wire is only energized while the starter is engaged (while cranking, not in Run mode). Once the starter solenoid is disabled, this wire is open circuited. Just dead weight while you're cruising down the highway.
(This wire is also backfed from the ballast resistor line, but that's a topic for another day.)

 

Remeber it's a current issue with HEI's as they require more current than the older coils. That's why newer HEI cars have a heavy gauge wire to the HEI.

When I do a retro fit I use the old "ign" wire to activate a small relay mounted to the firewall. Ground the other side of the relay coil to engine for a ground connection. I then take a 12 gauge wire from the starter battery connection to one side of the relay and then the other side of the relay to the Batt terminal on the HEI. This is simple and has never let me down. The car will run using the old wires but it's at higher RPM when you're pulling a lot of current and a much higher rate that the problems shows up.

The system works by shorting the coil to ground drawing a lot of current through the ignition coil primary. When the HEI module opens up, current stops inducing high voltage on the secondary ignition coil.

 

Hmm.....
On my old setup, there was a wire going from the starter to the coil. At the coil it was mated with another wire. This one apparently goes inside and feeds the water temperature gauge (or feeds from it). WTF?

 

http://www.madelectrical.com/catalog/hei-1.shtml

Here is a link to a HEI wiring kit.

 

That kit looks simple enough. Would be nice to have the factory-type connectors. Otherwise I assume they just run it to an IGN source.

I have mine connected to the IGN terminal on the fuse block. I suppose that's sufficient. Maybe I'll run a relay at some point, but I don't see an immediate need.

 

Simple explanation. On the old (points) setup, the factory provides two sources of current (Not Voltage. If someone says voltage, ignore everything they say about ignition systems). During normal starting and driving conditions, the ballast resistance source ensures sufficient magnitude of current to charge the coil properly, but also limits that current to around four amps max to keep from burning up the coil or points if you happen to leave the ignition on (while listening to the radio or if the engine stalled) while the points happen to be closed. In a perfect battery world, this single circuit would be all you need. However, those of us who do or have lived in the great North know what it's like to try to start an engine on a cold winter day. The thick oil and lower chemical efficiency of the battery during cold conditions can cause the starter current to drag the battery voltage down to 6-8 volts. At this low battery voltage, the ballast resistance and the coil winding resistance will not allow sufficent charging current to flow through the coil to provide a reliable spark for ignition. Enter the starter solenoid shunt wire. This wire becomes energized (with 6 or 8 volts, depending on what the battery voltage was while cranking) and it is wired directly to the coil C+ terminal. This allows non-resistive current to the coil (limited only by the coil winding resistance) to help the engine start during low battery voltage conditions. When the battery voltage is at the nominal 12 volts (during the summer, for example) this shunt circuit is just dead weight.
There it is. The reason for two wires going to the coil C+ terminal.

 

Now how about fixing my stereo problem that seems HEI related?

 

I didn't read the whole stereo post, so I'm not up to speed on the problem. (Feel free to give me a Cliff note version.) Generally a capacitor on the feed lines, and maybe an inductor (choke) on the stereo power line might reduce the noise coupling. But then again, I didn't read what the problem was. (I just listen to the engine/exhaust in my Corvette for listening pleasure.)

 

That wires only hot during cranking, for a little 'push' to get the car started. The other -resistance- wire from the fire wall main coupling is used to run the ignition, and shouldn't be used with an HEI, it's wants full 12+ volts. C.

 

I used Running Man's (thanks!) method for running a new switched 12V line from where the resistance wire orginated in the fuse box. I pulled the resistance wire and threaded a new wire to the 12V connection on the HEI.

Now to connect the electric tach from a 75. I know I need to run the signal from the HEI and a ground wire to the nearest ground. The real question is the 12V switched to the pos spade on the tach. Can I splice into my new 12V wire that runs from the fuse box to the HEI without any issues? I am not electricaly savvy so I dont know if I will overload the wire since it is feeding the HEI too. Hope that make sense.

Thanks for your help and have a great 4th!

 

I wouldn't do that. it's fed from the ignition from the key switch. It wouldn't be a problem, but may have some Spiky kick-back from the HEI, as the HEI is pulsy, when it runs. I would hook it to the accessories "ACC" spade lug in the fuse panel. keeps the install clean, no bubba. i want to ask, also, do you have the tach filter? you may not need it with a modern HEI, but if you get reading problems, i would install one. It goes inline with the tach read/signal wire http://www.ecklers.com/product.asp?p...7&dept_id=1135

 

OK. Purchased the filter just in case.

I already have the power window harness plugged into the ACC spade. It does have an extra tap though. Do you think there would be any issues using the extra tap?

Of course now that I looked down under the dash I want to pull the pedals and replace the bushings and boots.

 

why not use a relay with direct power from the starter always on lead as the power source and use the stock distributor lead to activate the relay?

 

No bubbas. yes you should be able to use the extra tap w/o a problem. be sure to watch the routing of the wiring, keep it away from sharp surfaces and hot surfaces obviously. grommet the hole in the fire wall if you can. Can't remember if i grommeted mine or not. :o

 

I'm wiring up my 69 from a 4 year body off and also installing an HEI and a mini starter. I went through all of the harnesses over the winter and fixed all the issues that I found with it. So I'm trying to get the car started and find I only get 6 volts at the HEI. I ran a new 10 gauge wire to the connector block at the firewall. I had a donor harness so I took a connector out of it and soldered it to that wire. I kept the old wiring for the coil in the harness, but and just tied it back for potential future use. I also took the starting boost wire off the starter.

So why the voltage drop, is there a resistor wire in the interior harness on that circuit? Update- took all the harnesses and made sure the connectors were clean and good and all is well now getting 12 to the HEI.

Besides this I'm not getting any power to the starter Solenoid so have to track that down also. Update- I found there are two connectors that at least one needs a switch a clutch and neutral safety for an auto and I have neither but without one being closed, no power to the starter.

This what I did same as glyingman21

 

except there is no immediate need, nor is there a long term need. A direct #10 to the IGN connection does the job! End of conversation. Tape off the old wires and move on!

 

Thanks for your help. Have a great holiday!

 

I'm not sure why the 6 volts. There is no resistance wire in the dash harness, the only resistance wire is the red yellow and white striped (may differ) wire coming out of the box that you said you tied back. I would back-prob at the connection on the box to see if you are getting 12v at the start of the new wire that you installed, it may have something to do with you not getting any power to the starter solenoid. Witch connection on the box did you put your new wire on?

 

The new wire went into the same connection as the old resistance wire came out of. I think there is a problem elsewhere as I'm getting 6 volts at some of the fuses I was getting 12 at yesterday.

 

Hey guys, I am digging up this old thread because I am having a similar problem, but not exactly the same issue as the OP. I installed an HEI ignition from summit. Now that I have the car starts differently. I crank the starter, but it will not catch and turn over. Then when I let off the key sometimes it will fire up. I am getting different advice on what the solution is. One tech at summit told me that it was the power issue described in this thread. I did use an existing wire from the coil/points dist to power the HEI, but a different tech told me that the issue might be a "jumper wire" on the starter itself that isnt compatable with the HEI and needs to be removed. Has anybody heard of someting like this? Also what are your opinions on the problem I am having? Not enough juice during cranking?

Thanks for the help!

Matt