Ground Wire

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HEMIHUNTER

HEMIHUNTER

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Ok, so I'm sitting in our 68 Barracuda trying to start it after putting on new fuel lines, hood is up and I'm watching the small ground to the rad support smoke, then turn bright red and slowly melt the casing....longer I crank the engine brighter it gets, BUT the car runs GREAT...WTF................
 
The larger ground wire is weak. The smaller wire is trying to carry too much of the load.
 
Thks, the large wire is a foot long and goes right to the head next to it but it looks fine, should I just replace it???
 
You could get a ohm meter and check it first. Or you might just give it a good yank and the end terminal will fall off ( guessing ).
The starters ground path should be through that wire. Reading your post suggests the starters ground path is through the firewall ground strap and the core support ground wire ( the one that melted ). That little ground wire was added for the headlights and such only.
 
It's very common for cables to corrode internally, under the rubber molded cover or under the insulation, so that a say, no4 gauge cable becomes effectively a no. ?? 14, 10, whatever, but way too small.
 
You need to clean both ends of the ground cable’s attachment going from battery (-) to block, or perhaps replace it if in bad shape.
 
You can always upgrade that ground wire too. Clean, clean, clean all connections!!!!
groundwire.jpg
 
I am confused. Does the wire that smokes goes from the radiator support at the front to the engine? If so, that does the same thing as the wire that rob_robinson87 shows going to the firewall (do you have that one too?). Regardless, how does the starter current get from frame to BATT-. Maybe 68's have another wire for that. My early A's just have a thick wire from BATT- to the engine.

One of my Mercedes started smoking the speedometer cable when I cranked the engine. It had a thick ground wire from tranny to frame (and BATT- to frame), but aluminum is notorious for corroding, so I cleaned it off. Same problem from the alternator housing in Mopars.
 
Used to sell lots of Datsun B210 accelerator cables back in the day, too, they would heat up and melt the sheath looking for a good ground.
 
FYI, a resistance check on this may not show anything. If it has 99/100 broken strands in the wire, the remaining wire will still have full continuity.

What you want is a voltage drop test. Measure the voltage from one end of the wire to the other while you're cranking on the car, and while it's running. If it's more than something on the order of .2 volts, it's too high and there's internal corrosion or breakage.
 
Ground cable ends are not full of oil are they? Had a car with a leaky valve cover that dripped right onto the ground cable. It would run down & collect in the cable end. Drove me off the wall til I made new cables for it...
 
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