Hello,
I've been having a problem recently with my car cranking sometimes when I get it warmed up a bit. It is especially apparent if I purposely run it hard and get it really hot.

Advanced tested my altenator as bad so I replaced it, and since then the problem has continued. I've also replaced the starter.

Today I purposefully ran the car hot to duplicate the problem and when I stopped the car turned it off and tried to crank it back up the problem occured again. And this time I saw smoke coming off one of the ground wires (the small one in the attached picture). The problem is usually short term, if I let the car sit for 5 or 10 minutes after turning it off then it usually cranks back up without a problem.

When it has the problems with cranking the motor turns over really slowly as if the battery is dead, and sometimes it doesn't turn over at all and I've heard it make a sparking sound.

Anyone have any idea what might be going on? I'm guessing that wire isn't supposed to melt and smoke lol.

 

you need to clean the battery terminals. very clean. take the cables off the battery and soak them in water. water only for about 20 minutes. then pull the ground cable off the engine and clean it really good. then put a meter on the positive cable and see the resistance. report back.

 

Most likely have a bad connection on the main ground cable.
Power from starter when cranking that should be going to battery Neg - on the big cable is going through the small ground cable instead.
Cable is not big enough to support the amps needed for cranking so starter turns slow and wire is burning up from being overloaded.
Check and clean both ends of ground cable

That is a dead giveaway that you have a bad / loose connection somewhere.
The fact you have the problem when hot indicates that something is expanding and not making a good connection that is OK when cold.

 

Ok, I replaced my ground cable completely today. Cleaned the contact points before replacing it, also cleaned all the contact points for the hot lines.

Same thing happened. I'm wondering if it might be a bad altenator, even though I just replaced it, or maybe a bad battery? I noticed while driving it the harder I pushed the car the lower my power gauge dropped. When I got back and turned the car off and then turned the key back on it read just above 8 volts. Trying to crank it resulted in dead battery type of behavior.

Waited a couple minutes even left the key on and watched the voltage reading slowly increase, when it got to ~10 volts I tried again and it turned over and cranked (still a little slower than normal but fast enough for it to crank). Let it run for a few minutes and it slowly built back up to around 12 volts and seemed to even out there. After that turning it off and cranking it again had no problems.

I don't know if the new wire was burning any after replacing the ground, it was starting to get dark but I couldn't see anything, will check again tomorrow during daylight.

 

Well, just another update. I got the battery swapped under warranty today (It was only about a year old with a 3 year warranty), and I think that has corrected the problem.

I ran it hard for about 45 minutes and heated it up pretty good and couldn't duplicate the problem today. The voltage meter also never showed lower than ~11 volts. (guessing since it only shows 8 and 13 hehe)