Faulty starter solenoid killing car?

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Witchboard

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I drove to school to pick up my daughter and turned off the car. Daughter hopped in and I turned the key. Started for literally a second and then nada, like dead. No lights, no nothing. I got my daughter taken care of and started troubleshooting in the school parking lot. Last thing I did was pull the cluster to take a look at the speedometer. I thought maybe I put something back wrong, though there's not much on it.

Disconnected the battery, pulled the cluster, reseated everything and sprayed it with contact cleaner. Put it all back together and connected the battery. Boom. Started right up. Shut it down again to put all my tools away. Stowed everything, hopped back in the car and nothing. WTF? I pulled it all again and started checking with a multimeter. Started at the battery.

12V at the battery.
12V at the starter.
2V at the 12V fuse. ??
2V at the ammeter. ??
2V at the alternator. ??

Checked the wiring diagram. Started running the components. The horn works, but nothing else. Found that if I disconnect and reconnect the yellow wire at the starter solenoid, I get 12V again. Tried staring, same thing. Once the key goes to run, it drops to 2V. Disconnected and reconnected again. 12V, started right up. Thought I should get it home while the gettin' was good. Was sitting a red light, car dies. Same thing. I managed to hop out, pop the hood, reseat the yellow wire and restart the car all before the light turned green. Gave thumbs up to the driver behind me and got home.

So is the solenoid what's killing the entire car or am I barking up the wrong tree? It's a 1964 Barracuda, but it has a 1973 225ci slant 6 installed.

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I guess I should correct myself, it's the starter relay. The battery is brand new. I'll clean the connections and the grounds and see if it makes a difference. Not sure why reseating the yellow cable would fix everything though.
 
Check/clean the bulkhead connector contacts (the yellow wire if I remember correctly).
 
What is "2v at the fuse?" Fuse link up by the starter relay? You have likely found it, either the link is AFU internally, corrosion, etc, or a bad connection right there such as the eyelet terminal on the relay end of the fuse link

Also you must be careful evaluating and taking voltage readings UNLESS you have a load on the circuit. Voltage drop is caused by current flow, and if everything is off, there is no flow. Things could show fairly normal and still have a bad connection
 
67Dart273 said:
What is "2v at the fuse?" Fuse link up by the starter relay? You have likely found it, either the link is AFU internally, corrosion, etc, or a bad connection right there such as the eyelet terminal on the relay end of the fuse link
Click to expand...

I was checking voltage at the fuses under the dash that are always hot. I was not aware there was a fusible link on the relay. I'll check that out tomorrow.

I cleaned the battery terminals and pulled the bulkhead connector contacts. Used sand paper and electronics cleaner in the bulkhead connectors. Seated everything back and nothing. I didn't check the voltages at the dash, but I was getting 12V at the alternator. When checking voltage at the post on the relay, it was 12V as long as the yellow cable was disconnected. With it connected, it was all over the place. I reseated the bulkhead connections again and got power. I guess I'll just have to see if I can reproduce the issue. Not really liking the idea of running around in the car waiting for it to happen troubleshoot on the side of the road.

I did ohm out the yellow cable on the relay and it does not appear to go to any of the bulkhead connectors. I'll have to check the schematic and see where it goes.

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The diagram says the yellow cable goes through the bulkhead and to the ignition switch. I'll have to pull that wire and see if it's broken at the blade connector.
 
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Pulled the cable connectors at both ends and tested with an ohmmeter. I think the cable is broken internally under the insulation. Both crimps look good, but when I flex the cable back and forth I get intermittent continuity. Looks like I'll be replacing that cable between the relay and bulkhead. Thanks guys for the help.
 
Replaced the yellow wire. I guess we'll see if it's a long term fix. I am concerned now though. I can't seem to find any fusible links. I don't know if that's because the previous owner may have removed them during the engine swap or maybe I just don't know what I'm looking at. I'm not seeing any reference to fusible links in the wiring schematic I'm looking at and the service manual only refers to it once in regard to the voltage regulator.

Also, something else I've found out, since they converted this to an automatic transmission, it appears the starter relay should be grounded through the park, neutral lockout of the gear shifter (neutral safety switch). They currently have it grounded directly to the firewall. I haven't tried to start the car in gear to confirm, but this is what I expect the behavior would be.
 
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If the relay has the separate ground terminal it is a simple matter to run 1 wire to the transmission
 
67Dart273 said:
If the relay has the separate ground terminal it is a simple matter to run 1 wire to the transmission
Click to expand...
Yup. Doing that today. Also correcting some other cabling they did for the reverse lights to the transmission they have sandwiched between the firewall and a metal plate. Pulled the cables, drilling a hole in the plate and installing a grommet. I'll use the same hole for the neutral safety switch.
 
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