1973 Chevy Nova 1973 Chevy Nova ignition problems

APAYNE87

MEMBER
1973 CHEVROLET NOVA

Electrical problem
1973 Chevy Nova V8 Two Wheel Drive Automatic

The symptom with the ignition system started after letting the car sit for 3 days. I went to start the vehicle and when I turned the key to the start position the car attempted to start for about a second and then everything completely shut off. After that whenever I turned the key to the start position the car would not even attempt to start and all of the lights on the dash would go out. The only way I could any lights to come back on was by removing and replacing the battery cables. I had the battery tested and it was fully charged and in good working order. Battery connections were nice and snug as well. I then had the starter tested and it was also in good working order. So I ran continuity checks on the wires that connect to the starter solenoid. All of the wires that connected to it showed 0 resistance except for the wire that ran from the most right terminal. The wire runs from that terminal to the alternator. At first it showed completely open until you place the key in the start position then it shows about 2m ohms. I inspected the entire wire and everything appeared to be fine and all connections seemed pretty clean. I'm not sure if that wire is supposed to have that much resistance. After cleaning up a couple of ground points. I put everything back together and the problem still wasn't fixed. I think the next step is the ignition switch, but I do not know how to remove it. Information on removing and installing it would be highly appreciated as well as any further troubleshooting advice in the event that the issue still isn't resolved. Thank you.

1 Reply

CARADIODOC

MECHANIC
33,742 POSTS

Hi apayne87. Welcome to the forum. Start by checking the small black wire that bolts to the body, and comes from the negative battery terminal. Next, start at the battery terminals with your voltmeter, then move the probes one at a time to the next place in the circuit until you lose the 12 volts. Have the headlights turned on because you'll be looking for a resistance that's going to be too small to measure, but you will see the results of it in a voltage drop at the point of high resistance.

Move the negative voltmeter probe to the body, and move the positive probe to the starter terminal. GM likes to use the starter terminal for a common tie point so they don't have to run a separate wire to the generator. If you still have 12 volts, look for additional red wires coming off the positive battery terminal and follow those.

A different but related test is to bypass the starter relay to see if it cranks. You can use a jumper wire, or, on newer cars, you can pop the cover off and squeeze the contacts. If it cranks, that will eliminate the high current circuitry. The reason then that it won't crank from the ignition switch is because the starter relay circuit isn't working. That would be more likely since it is in common with the dash lights and headlights.

Look for fusible links bolted to the large starter terminal. They won't be burned open because the lights work sometimes. But, look for burned areas that were too close to the exhaust manifold. Also poke around on the ring terminals on that starter terminal. If you see any sparks, disconnect the battery negative cable, then take those wires off the starter and shine them up.

Another common place to find an intermittent connection is where the wires go through the firewall. That's called the bulkhead connector. You can check for burned / oveheated pins in connectors under the dash too but usually you will smell them when they get hot.

Caradiodoc