I recently completed several small to medium-sized projects on my 69 Cutlass S, and now it's not starting and I'm not sure which thing I did to it is the cause of the problem. Before I worked on it, even though I hadn't driven it in a year, I did try to start it and the starter cranked like normal. I changed the transmission pan gasket and fluid, and before I tried to start it again, I installed headers, which of course involved detaching and reattaching all the spark plug wires as well as removing and then re-installing the starter motor. Now, when I try to start it, I get a single loud clunk as the starter tries to engage and then nothing. It's not moving the flexplate at all.

I had the starter tested to make sure it is working, and it is (though the man at the auto parts store said it wasn't tested under a load, but it seemed to work fine from what he could tell). The teeth seem undamaged. I double-checked all the spark plug wires to make sure they were firmly seated on the correct plugs, and I added more tranny fluid when I realized I hadn't added enough. The battery is providing plenty of juice to start (it's at about 12.8 V). Does this sound like an electrical issue? Or a transmission issue? Or something else I'm not seeing?

 

Can you turn the engine at the crank front nose by hand or with a ratchet?

What is the battery voltage while attempting to crank?

Good luck!!!

 

Id check the battery connections and wires the clunk may mean its not able to get enough current.

make sure ground is connected to the block and the ground strap at the firewall is present as well

 

Check the actual BATTERY cable to the starter. Sounds like the solenoid is kicking out the starter drive, but the starter motor itself isn’t getting power to crank the engine.


Since the 69 cars use the horn relay as a junction block, the rest of the car could be powered with the positive battery cable defective at the starter.

 

Turning the crankshaft bolt a little bit seemed to do the trick. It was enough that the starter was able to get it moving on the next try. I also had to add more transmission fluid and that seemed to help move things. I had a bit of trouble finding reliable info on exactly how much I needed to add after draining it completely, but I think I have it operating normally again. Thanks, all.