Battery wire gauge

[anlauto]

I'm leaning towards the starter too 

[Katfish]

More info, went back and looked at the cable I bought and learned they are CCA.
Apparently that is copper clad aluminum, and not very good.
I did a cold start, will try to load the video, it did start immediately, but voltage dipped all the way down to 8V and 7V after hot.
So either the starter is drawing excessive current, or there is a big drop on cable.
Best I can do is pic, 1st is cold, 2nd is after car idled for 10min and then started after sitting for 10min.

[Dmod1974]

An amp clamp will tell you the other missing piece of the puzzle and whether the starter is drawing too much, or you somehow have a connection issue only when hot. Still leaning toward a starter issue....

[anlauto]

When the car is hot and not starting, is any part of the cable or battery connection too hot to touch ?

[Katfish]

I'm definitely getting new copper cable to remove that variable, this CCA stuff isn't right for high current.
I agree, the hot part of the equation  doesn't make sense.
I'll take some measurements, and test drive it,  when the new cable.arrives and then go from there.

[Katfish]

Updating this to maybe help someone else.
My trans took a crap, so I was dealing with that.
Now that the trans issue appears fixed, I was able to verify the hot start issue is fixed.

I replaced the CCA (copper clad aluminium) wires with 00awg copper and that fixed the issue.
I now measure a 2V improvement in voltage drop when cranking the motor (9.5V vs 7.5V).

Not sure why it was only an issue when hot, but the pure copper wire works.
I guess there's a reason the CCA wire is 1/2 the price........

[dodj]

Not sure why it was only an issue when hot, but the pure copper wire works.
I guess there's a reason the CCA wire is 1/2 the price........

Electrical resistance in wires increases with heat.