Starter Gremlin?

[cv70chall]

I've run across something strange regarding my starter- and thought I had solved the issue- but apparently not.
1970 Challenger
440/ Auto
Relatively new starter
NEW Battery

Starts up fine when cold. 90% of the time, starts right up, whether having driven the car for 5 miles or 25 miles. Every so often, when I went to start the car, it would behave as if the battery was low. After several attempts, it would finally start. Initially, I thought it was heat-related, as this was happening generally over the past year. (I live in South Florida)
I purchased and installed a heat shield blanket over the starter to keep the heat down- and it seemed to work fine until yesterday- when after stopping twice, it almost wouldn't start- again, acting as if the battery was weak or dead.
Any ideas on what this could be? I will go back and check all the cables for corrosion, although I'm fairly certain they are fine.

[70chall440]

Check and most likely replace the positive lead down to the starter (the big red one), I had pretty much the same issue on my Challenger and in my case the lead was loose (which I discovered when I went to put in a new starter because I thought the one in the car was bad). I say "replace" because if it is an original one, they can and do corrode internally which draws a huge amount of amperage making starter act the way you describe; however you might just try cleaning the terminals really well and see if that helps.

Unless your headers are really close to your starter and/or you are running a high compression engine, it is probably not heat soak on the starter; many of those cars were sold and driven in FL as well as everywhere else its hot for many years without this issue.

[cv70chall]

I'll get under it over the weekend and check everything again.

Thanks !!

[jimynick]

Don't forget to check engine grounding as well as the hot side, because the current can't flow any faster or better than the conductor carrying it. 

[70chall440]

Don't forget to check engine grounding as well as the hot side, because the current can't flow any faster or better than the conductor carrying it. 

  well worth running a heavy gauge ground from your engine to the frame.

[cv70chall]

Thanks again.
Yes, I have a 4g ground engine ground from the block to the firewall which looks solid. I'll check the entire hot side when I get under it.

[jhaag]

Once you have exhausted all the possible electrical gremlins, check your initial ignition timing. Too much initial advance will give you the starting headaches you are describing. Also a "relatively" new starter and or battery could be the issue. Check it all...

[70chall440]

When you say it the ground is going from the block to the firewall, what or how is it connected to the firewall? I ask because I typically use nutserts to attach anything to the firewall because sheetmetal screws don't last all that long as they will vibrate loose and/or corrode relatively quickly

[cv70chall]

Hello everyone,

Got her up in the air, removed the blanket and all the connections from the positive side were fine- no corrosion. Decided to remove the OEM style starter and replaced it with a new smaller hi-torque model.

Fires right up!

[70chall440]

Outstanding!!! Congrats