Take a guess

[Gman73]

Wiring my hei trying to eliminate the resistor wire at the bulkhead stock 73 k20 all original harness. I’m trying not to have to unwind all the loom and tape back to the splice from the solanoid. See the pic which wire would you suspect?

 

[RaisedK5]

No need to guess

Thread '1973-1991 Wiring Manuals' https://www.gmsquarebody.com/threads/1973-1991-wiring-manuals.14498/

 

[Gman73]

I have the factory wiring manual specific to the 73 but I’d doesn’t add up, trace it from the splice it says color PB and to junction 3 for the life of me I don’t see the wire and it shouldn’t be that difficult it’s 18 ga

 

[RaisedK5]

Pink one should be #3

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[Gman73]

That’s what I thought also

 

[Gman73]

Thank you I’m going that route

 

[Matt69olds]

Don’t use tape to rewrap harnesses. The factory used friction tape, you can get it for about 8 bucks a roll from summit. It’s probably available other places.

Electrical tape doesn’t last long under hood before it’s gets gooey and starts to unravel.

 

[WP29P4A]

I have been working with low voltage wiring for 44 years and never heard the term "resistor wire", is this a wire with specific resistance that is used instead of a ballast resister?

 

[Redfish]

I have been working with low voltage wiring for 44 years and never heard the term "resistor wire", is this a wire with specific resistance that is used instead of a ballast resister?

I believe it is in place to prevent ignition noise.

When I re-wired the 1973 Bronco it also had a Resistor Wire and it was that same Pink with Black Stripe colored wire. When I was initially trouble shooting the electrical system in that Bronco I was confused by that wire and had to call my Dad. He was disgusted that I didn't know it was for ignition noise...

 

[Turbo4whl]

The resister wire provides the correct voltage for the coil on a point system when the engine is running.

When the engine cranks to start the battery voltage drops, from the 12.75V or so to maybe 9 or 10V. If the coil was designed to run on 13-14V as the alternator puts out when the engine runs, coil secondary voltage would be low on start up.

So the coil is set to run a lower voltage. When cranking, the coil receives current from the R terminal at the starter. This is the battery voltage while cranking, 9-10V.
When engine starts battery voltage jumps to 13-14V. Then the resister wire (or mounted resistor) lowers the voltage the coil was designed to run at from the ignition switch.

This is why you cannot use this resistor wire from the point distributor for your HEI dizzy.

 

[75gmck25]

I believe most GM starters have an R terminal (steps down the voltage to 9 volts for the points while running) and an S terminal ( provides full power for starting). Once they switched to HEI you only need to connect to the S terminal. That always made me think the resistance is built into the starter solenoid, but up I don’t really know.

 

[WP29P4A]

The resister wire provides the correct voltage for the coil on a point system when the engine is running.

When the engine cranks to start the battery voltage drops, from the 12.75V or so to maybe 9 or 10V. If the coil was designed to run on 13-14V as the alternator puts out when the engine runs, coil secondary voltage would be low on start up.

So the coil is set to run a lower voltage. When cranking, the coil receives current from the R terminal at the starter. This is the battery voltage while cranking, 9-10V.
When engine starts battery voltage jumps to 13-14V. Then the resister wire (or mounted resistor) lowers the voltage the coil was designed to run at from the ignition switch.

This is why you cannot use this resistor wire from the point distributor for your HEI dizzy.

That makes sense. On Mopar stuff they use a ballast resistor to knock the voltage down to the coil after starting, but puts a full 12 volts to the coil during starting.

So, will a 1987 GMC 350ci TBI truck have a resistor wire even though it has electronic ignition? Or is this only on trucks with points?

 

[Turbo4whl]

Only point type dizzy.