Alternator ground burning up

[RangerBoi99]

I have swapped a 351 and mustang 5 speed into my 1999 ranger with an auto wiring harness. whenever I crank the truck its will crank very slow and burn up the alternator ground wire (old style ford alt with voltage regulator). I currently have the crank relay bypassed because the truck would not crank on the key. any ideas as to why the ground is burning up?

 

[franklin2]

The starter is trying to use that smaller ground wire. That means your large ground wire from the battery to the engine block is not doing it's job. The electrical will take any path it can to get to it's destination. If the large ground is not good, it will take the smaller ground wire and burn it up trying to turn the starter with it.

I have had the same thing happen with my winch on my trailer. Big ground was loose, so the smaller lighting ground was taking some of the load and melted the insulation off of it.

 

[Shran]

Sounds to me like you're pulling power for the starter through the alternator somehow or the alternator ground is connected to power?

Really hard to guess, sounds like some wiring is way off.

 

[scotts90ranger]

I'm pretty sure franklin called it, it's the most logical but yeah, what Shran said, some wiring is jacked somewhere

 

[Uncle Gump]

Current takes the path of least resistance.

It's easier for the starter to ground to the alternator then it is to the battery.