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Starter relay stuck closed now engine won't fire

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Finished the fuel system on the 68 today. Took a while to get gas up to the carb, so it cranked quite a bit. Finally starts and is running great, but engine speed increases, forgot to hook up the return spring on the carb. Shut it off, attach spring. Try to start it again and relay makes a click/clunk/buzz noise but makes connection and spins starter. Engine won't fire.
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I trigger the MSD box with the original + coil wire which in start mode should provide 12v to the relay turn on the box. If I understand the circuit correctly, during starting mode the 12v to the + side of the coil comes from the I post on the relay. So then I wondered if the relay is bad based on the noises I heard. The next time I crank it, it doesn't start and the starter won't stop. Had to pull the cable off the battery. So to get to my question, when the S terminal energizes the relay, does the relay pass 12v to the I post? Could whatever fried inside be the reason the MSD won't trigger on through the coil wire? Decided to mess with it tomorrow, get a new relay and start checking voltage in the ignition system. Am I on the right track or is it two separate problems? Any of you wise men have any ideas?
 
So to get to my question, when the S terminal energizes the relay, does the relay pass 12v to the I post? Could whatever fried inside be the reason the MSD won't trigger on through the coil wire?
Click to expand...

Indeed, when the S terminal is energized, it passes full battery voltage to the I post. If the starter solenoid is bad, that portion of the relay may be bad. People have had some luck hitting the starter solenoid with "love taps" to get the mechanical relay to work, but I have always viewed that as a sign of impending failure. YMMV.
 
Thanks for the insight, off to NAPA. I should have known better than to use the original relay. It hadn't had power to it in 24 years.
 
You should still be able to signal the MSD box from what used to be the + coil wire, even if the starter relay is bad. I think you have at least 2 problems.
 
New relay and all is well. It moved under it's own power today for the first time in 24 years. Battery voltage was low, around 12v. I know MSD says it will operate on less, but that is not my experience. Had to jump it to get enough juice to crank and fire. By the time I got the cable off yesterday, the starter had pretty much sucked the battery. Need to replace the regulator now. DVM shows voltage at the battery while it's running bouncing from 14v to almost 18v. The reg is vintage also so I'm sure it will fail soon 'cause that's what old stuff does when I think it will still work. Pulled the power top switch to see if the top would move. It groaned and the switch smoked. I gotta figure out how to keep the smoke inside the wires on this car. At least the brake lights work.
Sorry Rick, no pics or video.
 
OK...a bit of obscure advice for pre-1968 owners. With the VR not regulating the alternator output voltage, that means the VR is not operational. It turns out that in years prior to 1968, the VR gets its energizing signal from the ignition switch, whether it is in ACC or RUN. Putting the key to ACC means the VR now is energized, and will deplete your battery very quickly. For 1968, Ford finally made the energizing signal from the ignition RUN line, so the VR is only energized when the key is in RUN.

Also, do not run the car any more with this VR. You can easily over-charge the battery, allowing hydrogen gas to be generated (can you say sparks?) or the battery to explode. Best to disconnect the battery until the VR is replaced.
 
Thanks again for sharing your knowledge. I disconnected the battery when the feed from the relay to the top switch started to warm up. Off to NAPA again.
 
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