The starter, solenoid, and battery cables have all been replaced, so why the smoke coming from the ground wire?

Dear Car Talk

Dear Car Talk | Aug 01, 1997

Dear Tom and Ray:

I have a 1977 Mercury Marquis, sold to me by a family friend, that has been a
money pit and the bane of my existence for two years now. The car was getting
more and more difficult to start. One day, I had the hood open while my sister
was trying to start it. I heard a click, fizzzz, and I saw the end of the
ground wire smoking. After that, when we turned the key, all we got was
clicking from the solenoid, but nothing else. I had the 6-month-old battery
charged. The lights and radio go on, but the car won't start. My brother-in-law
replaced the starter, and sis and I replaced the solenoid and battery cables.
Still nothing. It seems that we're not getting power to the starter. Do you
know why? -- Colleen.

RAY: I think you are getting power to the starter, Colleen. The problem is it's
not getting back.

TOM: For an electrical device to work in your car, current has to make a
complete circuit. It has to go from the positive terminal of the battery, to
the device, and then back to the negative terminal of the battery. And the
typical path back to the negative terminal is through the engine block. And I'd
be willing to bet my brother's salary this week that the ground connection
between engine block and the negative terminal is faulty.

RAY: Here's how you verify this. Take half a set of jumper cables (for example,
the black pair) and hook one clamp to the negative terminal of the battery, and
the other clamp to some substantial piece of metal on the engine block. You can
even wiggle the clamps around as you try to crank the engine. My guess is that
it will fire right up.

TOM: Even though you've replaced the battery cables, you didn't fix the
corrosion that's keeping the negative terminal from being properly grounded to
the engine block. And in a car that's 20 years old, that's almost certain to be
the problem.

* * *

RAY: Hey, did you hear that our new pamphlet, "Ten Ways You May Be Ruining Your
Car Without Even Knowing It," is a million seller!

TOM: That's not what I said, you knucklehead. I said I had a million of them in
the cellar!

RAY:Oh. Well, it still has lots of good information on how to make your car
last forever.

TOM: Order your copy of "Ten Ways You May Be Ruining Your Car Without Even
Knowing It!" by sending $3 and a stamped (55 cents), self-addressed No.10
envelope to Ruin No.1, PO Box 6420, Riverton, NJ 08077-6420.

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