Hi all,

I inherited a 73 small block from my late mechanic father about a year ago and it is driving me up a wall. Admittedly, I am enough to dangerous mechanically but am handy enough so have been trying to figure this out on my own to no avail. So hoping for some sage advice from the experts.

The car has no spark. On key turn, the starter & everything else will go but nothing to the plugs. I have checked the distributor, connects, & coil and all seems fine. I am convinced my father installed a kill switch somewhere that is not allowing power to the coil because he had installed one in every other vehicle he has owned. I also found a small alligator clip jump cable near the pedals and I am convinced this was used to connect something. Might be a red herring though. Who knows with my father.

​​​​​​Any way, ​I have a few questions:

1. The fuses all look good but there is nothing plugged into the "batt" plug. My reading is that this is for auxiliary gauges but can someone confirm.

2. Coming from the "acc" plug on the fuse box there is a split connecter.i believe this stays unplugged?

3. Any advice on how the wiring from the coil runs so that i can trace where it is getting cut off? I feel like I may have to take the dash out but wanted to ask before I did.

Apologies for my lack of knowledge but really appreciate any help.

 

The wire from the coil goes to the ignition switch. This is located on top of the steering column about halfway between the pedals and the dash. There's a large wire connection on the firewall just to the left of the distributor that you can use to hotwire it so you could start and move the car. If your dad installed a kill switch then your best bet is to trace the wire off the coil back under the dash. Good luck! Keep us posted.

 

Welcome to the forum. When I get home, I'll try to check my factory service manual wiring diagram for the BATT fuse. The coil gets voltage from the ignition switch as 74HARLEY stated. But there should be two connections. One from the start position and one from the run position. The start position will bypass the ballast resistor that is designed to limit the voltage during running. This allows full battery voltage to the coil during the start position which gives you a hotter spark. By limiting the voltage across the ballast resistor during run, it minimizes the burning of the points due to the less current going through them.

 

Thank you for the help and patience with my lack of knowledge.

That would be the reason there is 3 wires going to the positive on the coil then? One for the run, one for ignition,and then the last I assume for ground.

Also, the circled large wire connection is where I can hot wire it from? I assume so but better safe than sorry.

Thank you again

 

There should be two wires to the positive terminal on the coil and one wire for the ground. Attached are a couple of pictures taken from the factory service manual.

 

Fantastic, thank you. I have time to dive deeper this week!

 

Not sure what the circled red component is but mine has something similar looking mounted on the firewall nearby. It doesn't look like a typical GM relay so I'm wondering if it may be a thermal switch.

 

I noticed that the engine has fined aluminum valve covers which only came on the L-82 version and 73. If it has an 8" diameter harmonic balancer, then it probably is an L-82.

 

I believe that unit is a circuit breaker. You should be able to hotwire it from there.
However, it's also a good idea to check for power at the coil. If the car has been sitting a long time the points may have corroded and you won't have spark. Same issue if the condenser died.